Picture of Mousebot Revisited
Mousebot from Make vol 2 is a fun introduction to robotics. So fun that I've created this expanded documentation of a Mousey build from start to finish, with a few extra little tips you won't find in the mag. This how-to is best understood after reading the original article from page 100 of Make vol 2 however it is probably not required.

Mousebot is a simple bot that uses two "eyes" to sense light and then turns towards the light. A single large "whisker" is mounted on the front of the mouse to detect collisions. A collision with a wall will cause the mouse to reverse and turn then take off in another direction. This project is pretty cheap, if you have a mouse to use the other parts can be obtained for less than ten dollars.

If you have any questions or comments you can get me at
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Step 1: Gather Materials and Tools

Picture of Gather Materials and Tools
1 Ball Mouse
2 Small DC Motors
1 Toggle Switch
1 DPDT 5v Relay (Aromat DS2YE-S-DC5V works)
1 LM386 op-amp
1 2N3904 or PN2222 NPN Transistor
1 LED (any color)
1 1K Resistor
1 10K Resistor
1 100uF Electrolytic Capacitor
1 Audio Cassette Tape (you know, from the 80s...)
1 CD-ROM or Floppy Disk (for the bumper)
1 9V Battery Snap
1 9V Battery
2 or 3 Wide Rubber Bands
22 or 24 Gauge Wire (some stranded and some solid core)

Phillips screwdriver
Small pliers
Wire cutter/stripper
Razor knife
Soldering iron
Desoldering tool of choice
Superglue or epoxy
Hot glue gun and glue

Step 2: Scavenge some parts

Picture of Scavenge some parts
The Mousebot requires several parts which we can conveniently borrow from the donor mouse, its eyes and its whisker.

Open up the mouse and locate the components that we'll be harvesting, the momentary switch and the infrared emitters (the clear ones).

Remove the PCB and desolder the push switch and both IR emitters.

please give me a video making !!!

very creative mind

freddyjefrie4 months ago

great stuff

nospleen9 years ago
Wow, lots of comments here since I last was on. I have finished building my mousebot. Here are some pictures: I used Radio Shack's LM386N op-amp and it seems to be doing fine. I had to order my relay online. The best deal I could find was from They had the exact part for $2. Worked great. Hecbot, regarding the LED. Did you wire the sensitivity boosting circuit with the revised schematic on I used that schematic and my LED lights up. The sensitivity of the IR beams seems to be pretty good too. I would think that there may be a problem in your circuit, although it may not have one. Check to make sure that the negative and positive are in the right spots, because the LED won't work otherwise. Stephen: that stinks that your bump switch isn't working. Did you check the poles on the switch to make sure that you didn't break off the wrong one. Out of the two side poles only one is connected to the switch, and that is the one that should be connected to the cap and the timer resistor. Other than that, I would just take a good look over the schematic and compare it to your circuit. I know that a few times I had some miswirings and they can drive you crazy! Also, I had a relatively small mouse and I had to cram it all in the case. My motors are also larger than normal, I took them off of an old xMod RC car. This has a been a fun project! Erich
62 comments to be exact.
robotix robotix8 years ago
Now 65
robotix robotix7 years ago
Now 117!!!


rimo nospleen2 years ago
have u yoused that ?
backcountry9 years ago
I finished my Mousebot over the weekend. It works perfectly thanks to the correct schematic at: The kids and cat are impressed. I made a rubber bumper by cutting a rubber washer in half and hot glueing it around the front of the mouse over the switch. Several mechanical challenges. The case doesn't close completely so I'm holding it together with rubber bands. And the back end is so battery heavy that it often can't get enough torque to back up. And it likes to circle to the left which is actually a nice feature - less mouse chasing.

I learned a lot from this project and it really got my interest up in BEAM bots.
this schematic is better that the first init pliiiz repliie
trentcole rimo4 months ago

thank you

davejuniortwo6 months ago

awesome stuff .. gonna try that on my mouse

yep great

ameera7711 months ago

how many is it the DC dynamo size? and the size of relay? Please help :)

swolff12341 year ago
All I have is a LM358n. Will this work? 

yes it should...

Huuunksam11 months ago

This is a textbook quality Instructable !! Clear and concise - PERFECT!


Kelly Smith made it!1 year ago

Thanx! Going to make another now :P


This is a really neat project. Where can I get all of these things?

RIP Donor mouse.

toxiq20113 years ago

Hey, I just finished mine but unfortunately it does not work. Don't know what I'm doing wrong... One motor spins real fast & the other spins really slow.

Thought I had done some wiring mistake the first time & re-wired the whole thing again, but still the same issue.

Any guess's, adding in a pic of what I have as if now though.

hey dude i had the sam problem; once he had a circuit here and its different from the stuff he tells u; search for the circuit, it might be in the pdf
put a 200 ohms resistor 1 to 8 of the lm386
neoJunk8 years ago
Got this working a few weeks back. I had some of the problems other people have had, mainly one motor getting more power than the other. I found the bot worked perfectly in pitch black with one VERY bright light. It moves extremely quickly and the batteries don’t seem to last to long. It’s lots of fun!
rimo neoJunk2 years ago
wht have u used bro
Doddity5 years ago
+ is always the longer wire but look inside the actual thing and the smaller one is the anode (+) the larger one above it is the cathode (-) hope that helps
rimo Doddity2 years ago
which one is correct dude
thankyou very very very very very very much!
can i use a 12vdc relay, or can i use two relays?
The number on the relay is telling you how many volts are required to trigger the switch by sending the voltage through a coil between two pins. If your robot uses a 9VDC battery, then you will need a relay that can be triggered by about 5 or 6 VDC. A standard 9V battery won't trigger a 12VDC relay.

You want one Double Pole Double Throw (DPDT) relay rated for 5VDC or two Single Pole Double Through (SPDT) relays rated for 5VDC.

You can purchase and appropriate 5V DPDT relay from Solarbotics or just read more about how they work on their site.

Hope this helps.

Christin Boyd
rimo christinb2 years ago
which one is correct pliz help
christinb4 years ago
I found through some testing that putting a resistor across the gain (Pins 1 and 8) of the OpAmp chip (LM386) rather than just soldering them together gave me better results. Every robot will be a little different because we're all using different IR emitters or IR LEDs in our bots.

You can read about my experiments and how I determined that a 200 Ohm resistor resulted in my mouse moving in the straightest line on my blog.

-Christin Boyd
rimo christinb2 years ago
and also about the lm386 please help cuz i think that i fried them !!
rimo christinb2 years ago
im really impressed by your ideas !!! but i want ask you a question how can we know that IR light emitter works and not fired please help
chessman9083 years ago
i just finished making this and it doesn't work! i have no idea what i am doing wrong, it could be anything!
PLEASE HELP ME!!!!!!!!!!!
maybe like a schematic of something like that.
please respond ASAP! i am doing this for a science fair project and its due Monday!!!!! :0
......................or a circuit?
never mind i found something
wht waz your pbobleme brother because i also finished the project but it doesnt work ! please help me brother and i will be really thankfulllll ...thnx
rimo2 years ago
i've made the test in the bread bord when i on the toggle switch the motors run normally but the Led is still off .and when i put the light on the sensor they didn't work and also the bump switch didn't work :( :( :( please please help me i will be thankfull
cartilige5 years ago
I'm busy making a different project, but it requires a lot of similar components. I am looking for a LM386 op-amp but I'm finding it very hard to get, any ideas where I could get one. DO NOT SAY RADIO SHACK. I live in the UK and can't travel very far from Newcastle so where could I get one, if it is used in any household products I have aces to a whole range of them which I can strip down. Thanks
 you are retarted
You could maybe do some salvage.
Doddity coleyy5 years ago
jesus read what he wrote before you comment he said HE DOESNT LIVE NEAR ONE
maybe a amplifier? strip it down and try to find one!
some stores (I don't know what equivalent of jaycar is in england, maybe they have one) will mail your components out to you so it can be just a matter of searching electronics hobby stores in the UK and checking if they mail out to you.
go at radio shack man!
soundcard, modem, most devices that have an audio compononent. LM-386 is an audio amplifier.
black98206 years ago
Where shall i get LM386 in India Please suggest for it
sp road in bangalore
Jenowl2 years ago
Hi, i plan to do this for my project. do you think you can provide me with the circuit diagram? It would be really great if i could hv the circuit diagram. pls help :)
dany_114 years ago
this instructable is very cool..i want to try this one..but i have a problem. i had only found a 6v relay and it only has 5 pins..PLEASE I NEED HELP
the relay is for the backing-up movement of the mouse when it bumps to something so you can use that 5 pin relay for one motor only so instead of the robot backing up, it will just spins 'coz only one motor will reverse, here is my modified diagram of the mousebot. (and the corrected circuitry). i hope this will help you a lot.. Goodluck
well i did hav dpdt relay rather than spdt so was wondering how to connect 5 pronge. thank u very much for this.
luudvig4 years ago
I found it alot more esy to solder everything to a circuit board, here's a pic of my mousebot's brain.. :P
kiranrs luudvig2 years ago
Dude thnx for ur Idea , i have my junkbot ready and running thnx man!!
kidkid1083 years ago
how much will this cost in all?
mr.future113 years ago
i mthe beginner of electronics student. can i be helped by anybody of following members who hav tried this project. i would great thankful 2 him or her
ms103 years ago
its a very cool project simple and great can you tell me where did you get all those things
hi I can't find the lm386 chip but have a tda2822m. is this alright to use instead???
sparkspooky4 years ago
hoe do you make a simple robot without programming to follow light=(

A circuit like this should do the trick although you will almost certainly want some bigger transistors/ darlingtons.

When the light level increases the resistance of the LDR drops causing the NPN transistor to turn on. The sensitivity of the circuit is set by the fixed resistor with a lower value needing a brighter light to turn on the motor.

The point in having the left ldr hooked up to the right motor and vice versa is so that when light falls on it the robot will turn towards the light until the intensity is the same and then drive forwards.
Light follower.png
i might post how to post it it is really simple
just make a robot going forward or open up a tennis ball and put a vibrobot in to it then it will move around.
ilpug3 years ago
so, this is basically the same exact thing as the Herbie The Mouse-bot kit by SolarBotics, but built inside a computer mouse?
i know how to make a really simple one with two photo resistors and motors.
it only follows light
hi, this is a good idea, 5/5
be cool if u could do this with a still working wireless mouse and have it still be able to opperate as a mouse :P
R.A.T.M3 years ago
what voltage is the mortors
jwoo20235 years ago
Is the a mark?
wow thanks a lot
Vapolord5 years ago
i bulit this mousebot.
first i used a 32volt Electrolytic Capacitor ,but my battery was alwaysw dead.
with a 16 volt Electrolytic Capacitor th mousebot's battery has got a longer live.
both work....i hope i could help you jwoo2023
luckily i had the 16 volt!
mattstertx8 years ago
anyone now were i can get 2 Small DC Motors 1 Toggle Switch 1 DPDT 5v Relay (Aromat DS2YE-S-DC5V works) 1 LM386 op-amp 1 2N3904 or PN2222 NPN Transistor 1 LED (any color) 1 1K Resistor 1 10K Resistor 1 100uF Electrolytic Capacitor 1 Audio Cassette Tape (you know, from the 80s...) 1 CD-ROM or Floppy Disk (for the bumper) 1 9V Battery Snap 1 9V Battery 22 or 24 Gauge Wire (some stranded and some solid core)
dicksmith or jaycar
jaycar is probably the best thing for this so ill agree with this guy

jaycar rules lol
REA mattstertx6 years ago
radio shack.
here in Canada radio shack doesn't exist anymore
how is Canada still alive then!!!!!! D=
We still have it, it just got bought out by circuit city, so now its called "The Source - By Circuit City" - But its essentially the same exact thing
radioshack doesnt carry 5v relays
can someone tell me what a dremel looks like
After being on this site how can you not know what one looks like?
REA mattstertx6 years ago
heres a picture of one with the different tips.<br/><a rel="nofollow" href=""></a><br/>
This site is ridiculous:
D5quar3 coleyy5 years ago
here you go for the relay.
and Dremel Multimeter Desoldering tool of choice Soldering iron
a dremel will set you back about $60 if you buy it in Home depot. That's where i bought mine. Mine is series 300 41 accesories.
radio shack. or scavenge.
can i use a 6 notch relay? will that change anything?
jwoo20235 years ago
how do you know which pin is 8 and 1?
it is on one of the pictures
is there a mark?
I'll explain it a little easier. You should see a notch, hole, bore, or whatever a noticeable mark is called. If you lay it on a table with the notch looking up, and pointed straight ahead. top left =1 then going down its 2,3,4,then the bottom of the right side is 5, then going up its 6,7,8
A little imprinted dot on the top of the ic indicates pin one. It counts counterclockwise when you see the ic from the top. Pin eight is the last one on the opposite side of pin one as you see on the photo. Some ics have a notch on one narrow side, counting starts left of it. -
radiorahim4 years ago
When it turn it on only the left motor spins. When I cover the left emitter it spins slower, when the right emitter is covered it spins slower, but the right motor doesn't move. When I press the bump switch both motors move. Any Ideas?
I've had a similar problem. [I built mine a while ago from a printout of the make article.] I checked everything, and it still didn't work.
check the pins to the relay, you may have a different pin array, look up the datasheet for it.
check your connections.
sparkspooky4 years ago
beehard444 years ago
i don't get the purpose of the IR leds
n410gangwar4 years ago
if we dont have an old mouse can i use infrared LEDs instead of what found in mouse ?
gideon134 years ago
I want to make the mousey robot. I'm very bad in things like that and i've never maked a robot before.. And i think i can make it with your tutorial but.. Where en for how much can i get those materials ?? Plz help me..
coleyy5 years ago
ask the guys @ radio shack
 when has that ever worked?
 lol so true
 I asked if they had a 555 timer and they asked me what that is
I asked them for a headphone jack to solder, and they pointed me in the alarm clock section XD
FraKtuL D5quar34 years ago
I bet they know your phone # though! LOL
D5quar3 FraKtuL4 years ago

yyyyyy4 years ago
This is very neat. Cool.
Chris454 years ago
How did you do the training wheels?
pobturtle5 years ago
 Does anyone know why one motor spins faster than the other then when I hit the bump switch t(that makes it go in reverse) the motor that was going slower now goes faster. ???
It is because the reverse polarity makes it reverse the light seeking (light avoiding) But that is good because whatever light source is attracting the robot towards the obstacle, the robot will try to try to avoid it when in reverse.
Chowmix124 years ago
12v relay from Radioshack works perfectly! no worries! I wasn't able to make this robot, but I was able to use the relay with only 5v (4 rechargeable batteries) including transistor timer circuit.
Unreal X5 years ago
 wai tim kinda confused dont u want to use a IR reciver not an emmiter

in the mouse for the ball it is an IR emitter
the emitter is what sends the signals and they are calibrated to the certain mechanics of the mouse
Chowmix124 years ago
pratik12345 years ago
robart to ban gaya but chala nahi
mera ke liya bhi aisa hi hua
Chowmix124 years ago
i'm very new to robotics (and somewhat to electronics) and i ended up buying the wrong relay at radioshack (12v, not 5v). Is there any way to make this without the reverse mechanism circuit? i want it to be at the very least light seeking. I have been working on this for hours and I'm really frustrated... Later on I might find a relay to use and incorperate it but for now...?
domenicdom5 years ago
where can you get Aromat DS2YE-S-DC5V? Radio shack does not have it!
 so true
whatever happened to radioshack?
here you go,
 wow thanks
but i really prefer going to a radioshack near me to physically buy it
that way i know im not getting broken equipment and besides im underage so i cant pay online through a credit card
but thanks for that
np. radio shack doesn't sell it though which absolutely sucks. could probably frys if you live near one, but the customer service sucks.
Data6435 years ago
How would the robot turn if the op-amp only has one output? It would make the motors do the exact same thing. Would the relay help make it turn?
Mudbud5 years ago
yeah I agree with magiccowy.  you can use that techneec for all LEDs
Doddity5 years ago
M-jake seems to have abandoned this instructable can anyone help with which pins are which on the LM386 and the relay Thanks =)
ahlexys Doddity5 years ago
there should be a notch that shows the front of the chip, pin one is to the left of that on the lm386. the relay should have numbers on the underside indicating pin numbers. (well, at least the ones ive seen have.) ☺
Doddity ahlexys5 years ago
Thank you very much
Doddity Doddity5 years ago
sorry for the amount of comments but i add as i find if anyone needs the info pin 1 and 8 are closest to the semicircular mark on one side
jwoo20235 years ago
how do you know which side is + and - on the infra red emmitors?
jwoo20235 years ago
can we use heatshrink?
Doddity5 years ago
hi im building this at the moment i have the LM 386 but dont know which pins are which could you please help me
dany_115 years ago

i don't found relay 5 volts
please help me what shal Ido?

Walkerion6 years ago
Could you use a 12v relay instead of a 5v relay?
no because the main voltage is 9V so its to much
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don't spam.
it dosent matter
tompapa5 years ago
 Thank for all your help,,.but i wants to add Infrared detector so that my mouse can detect any infrared light in room..and turn towards it..plz help me..
dava_25 years ago
Can anyone upload me a .pdf file? I really need it, thank you
i need the complte documents about mouse bolt revised

please send to me

WBR - prabhu
hey where i got 5v relay? please help me ........
jwoo20235 years ago
Does anyone know what voltage the 100uF Electrolytic Capacitor is?
jwoo20235 years ago
what voltage is the 100uF Electrolytic Capacitor?
coleyy5 years ago
my uncle works with computors, so he gave me free parts. =) or you can do a smiely like this :>or this =-)
coleyy5 years ago
galchenko5 years ago
pas20075 years ago
Could you please tell me. What voltage of DC motors you used? If i buy Dc motor for 3 or 4.5 volts is it ok? Thanks.
I bought 2 9 volt DC motors for a little more power. 3 or 4.5 volt motors should work
pobturtle5 years ago
My LM386 pins arent labeled. What Should I do?
pas20075 years ago
Hello again Can i use 2 tv remote controls Ir emmiters? Thanks
frag master5 years ago
this would be cool, build a foam R2D2, put a Mousy in the front foot, extend the eye stalks to the top of r2s head, and presto, one really cool robot that will follow u around. now, if only i could install a taser......or a kick-butt pistol!!
Unreal X5 years ago
Unreal X5 years ago
frag master5 years ago
instead of using rubberbands, try using xmod tires. SWEET!
Unreal X5 years ago
one there a wheel in the back or something i skimmed tro this first so i didnt c
kohlious8 years ago
i have read through the comments, and it seems that noone has had this problem... my motors aren't getting any power at all! i switched the wires on them to make absolutely sure that i had positive to positive. they're new (from solarbotics) so i doubt that is a problem... the relay is definately doing... uh... something or another, the led lights up, and i can tell that the IR emitters are responsive by the different noises from the relay. what should i do? ...and could it have anything to do with overheating one of the resistors or something? i posted this on the first page, i figured it was too far down to be seen. sorry to clutter up ypur page, dude.
Most motors (I think all, but am not sure, so I said most) will work even if you put positive to negative. It just spins the opposite direction.. It's probably just broken for some reason, like "noobixide" said, check it with a multimeter. Try to get a different motor. These types of motors are found in a ton of places, you can get two out of a cheap $5 wal-mart CD player, old children's toys, etc. I got mine from a broken CD player so I wouldn't have to go buy them.
Check it with a multimeter....
Do we need to have this so called dremel? And if not what else can I use that might be eaiser to use?
Uh, a dremel is ... a dremel no real replacement... just use a knife. I can't believe you've never heard of one.
Why don't you guys just use slot car wheels and tires. HO scale should work. Kev
can i use a 12VDC Coil DPDT Miniature PC Relay from radio shack please some one respond to me
can i use a 12VDC Coil DPDT Miniature PC Relay from radio shack
redsierra5 years ago
More information requested, such as the motor type, voltage and size. Plus the wire gauge size is it American (awg) or British (swg). The only motors, I found were 3 -4.5 v, low torque, high rev.
i had an awsome idea but i need help i was thinking or recasing a mousebot in a u-repar wall-e can anyone tell me if the toy is big enough to house a mousebot kit
Any chance I could substitute the LM386 with anything else?
kyzerjade5 years ago
how 2 make a robot??? because it is needed for my project............
kyzerjade5 years ago
how do i make the robot mouse???
jwoo20235 years ago
Why are each brand different sizes and which brand was you cassette tape?
you can a LM386 in some old answering machaines
RetroTechno5 years ago
This is a clever project. However, the instructable has very little technical explanation of theory of operation. I think it's good to learn the why behind the projects. The original article is no longer posted at the Make site (I get 404 error page).
There's a good deal of info in a Q and A format at
such as why we should use EMITTERS to DETECT light. It will blow your mind. :-)
This is too complicated for me .can u plz draw a circuit diagram of this with all the pin numbers and connections clearly mentioned.PLz
This is the corrected circuit diagram of Mousey from the Make Magazine publishing.
guy1236 years ago
how do i remove the pcb from the mouse
don't you just pull upwards? i wouldn't think it was soldered to the actual plastic
Desolder it
pobturtle6 years ago
what are those mettle things next to the + and the - sign connected to?
positive and negative voltage rails
dowd955 years ago
i popped open my old wheel mouse and got the switch but IR things are nowhere to be found. any ideas?
it depends... some mice have this and some do not... just look for a gear-like mechanism, there is a black part, and a clear par on each side of the gear, you need the clear part. but like i said, some mice do not have this...
Do you use pin 7 on the IC?
Not trying to bum you out but, the mouse-bot kit from maker is really better. I just finished it and it;s really fun to make, there are a couple of tough pats (like soldering on the clippings to the transistor.. but overall it's a really great project and has better quality stuff to promise a well-working mouse-bot of your own.
Unreal X5 years ago
(removed by author or community request)
the toggle switch appears to be a master power switch :)
Unreal X5 years ago
this is an easy and cool project im like 12 years old and i find this as an awsume project
Dude this waz so awsome when you make yor next robot cn u tell me pls thanx
moesboy6 years ago
im going to try and use the mouse ball
chemy9996 years ago
ime trying to make a line following robot similar to mousey and i am trying to make headlights so that it can also go when it is dark i am trying to figure out what minimum value resistor to use i am using at max a 10v battery if i divide the voltage by the amount of amps something can handle i will get the minimum value resistor i should use how do i find out how many amps something can handle
slowslow3256 years ago
I cannot find a 5v dpdt relay in radio shack or any other store. I couldn't even find it on their website. Where can I find one? Is there any common electronic device that might have one that I can take from it?
I am really strugglin'. I can't get out the IR emitters and i'm afraid I might break it. Is there any way I can get it out? Please I need help...
I don't have desoldering tools; melt the solder and smack it on aluminum foil before it gets hard again.
get de-soldering braid(easily obtained from radioshack) and that heps remove solder from stuff, thats what i used anyway.
desolder them from the circuit board
vasiliy6 years ago
hey i have a hasco has112s realy will it work? it also says dc9 on the bottom but it doesnt say its volts because it doesnt have the v
vasiliy6 years ago
hey i have a hasco has112s realy will it work? it also says dc9 on the bottom but it doesnt say its volts because it doesnt have the v
Didrtan6 years ago
Does anyone know if a 5vDC relay will work it has four pins in back and one infront so its basicly all you need as far as pins go any help?
james146 years ago
anyone now what v motor you need
Doveman james146 years ago
I think 12V
rahulraman6 years ago
i have AN6605 ic can i use it in place of LM386
vengeance896 years ago
this instructable is very cool..i want to try this one..but i have a problem. i had only found a 6v relay and it only has 5 pins..PLEASE I NEED HELP
mzee2336 years ago
please help......! I couldn't find a DPDT 5v relay.....! but i found a DPDT 6v relay, but unfortunately it have only 5 PINS.....!! can I use it? if so......please instruct me how to wire the components to 5pins...!! please help........dis is the first robot project I'm going to do...!! i found all the other parts needed...!! Im very egre to watch it WORKS...!!! so please help me!!!
robotix8 years ago
I've got a question, I couldn't find a 5 volt relay so I just got a 12 volt I thought it might work because I'm using a 9 volt battery but I haven't tried it yet anybody got an answere? Thanks.
frikkie robotix6 years ago
It might be to weak.But try using an transistor to trigger the relay
must be 5v i think!
12v doesn't work. Yahoo Answers says so.
krode6 years ago
If you're just gutting it anyway, why does it have to be a ball mouse? And what about using the ball as the drive wheel, and have the motors inside... just a though :)
it is not needed but he says ball mouse because they have ir emitters and detectors inside along with the mousebutton and save some $$$
isolator6 years ago
hey is there any replacement of 5v relay...where can i find it in india? i m getting 12v relay.. please help me out!!
akashn isolator6 years ago
If you live in Bangalore you can go to Silver Jubilee Park (city)
HOWITZER6 years ago
all material list in ( steren ) exept dc motors.
akashn HOWITZER6 years ago
Then buy 2 DC motors they cost less than $2
akashn6 years ago
Can I please know what a radio shack is and where i can find one in Bangalore, preferably somewhere in Frazer Town (-:Help to be appreciated:-)
Redneck26 years ago
Coolest ever going to build it asap
Is there anything i can use an infrared LED for?
You can use it for many projects.... TV-be-gone's, proximity sensors, you name it..
hexbug976 years ago
i went to radioshack but they didnt have a 5v relay. is there anything i can take one from?
backcountry9 years ago
So I went down to Radio Shack for parts and got everything I needed, except they didn't have a 5v DPDT relay. They did have a 12v one though, so I got that. I haven't seen a definitive word yet on whether a 12v relay will work, does anyone know for sure? And if so, are there limitations? The scroll wheel from my disemboweled mouse looks like it would make an excellent wheel. Perfect surface. Only drawback is having to kill two mice. Will have to scrounge around at work.
I don't think that the 12V will work. I saw the same relay at Radio Shack and the problem was that it has 5 pins instead of the 8 pins that are needed. You can order the right relay online for a few dollars. I found the best deal at
krode6 years ago
Oh wait, you're using the ir components. I get it now... But would still like to see the ball driven internally. :)
baldo9 years ago
let's see some video!!!
pobturtle baldo6 years ago
There should be a video.
on youtube
does it matter what direction the resistors go in?
Resistors do not have polarity. So it wont matter which way they go in.
155841046 years ago
hello: I do not have a mouse. How then can I replace the switch by one purchased? and the two issuers, can I substitute for a few purchased?, that is two LEDs infrared emitters. now thank you very much sorry, my language is not very good because I'm Spanish
can you use CdS photoresistors instead of the IR emitters? or is there an alternative to the IR emitters because i don't have an old mouse, is there another place to get them?
I got mine for a dollar at Goodwill.
slowslow3256 years ago
Can I use a 5v SPDT relay?
stevie17 years ago
does anyone know if i could use a dual op amp instead of just an op amp??? thanks
The LM386 is very easy to get. You can even find them at radioshack
Ianic stevie17 years ago
You'd be better off with what it tells you to use.
barnes8 years ago
4521, that rubber band was around Scallions, or White Onions, at one point. (I'm a cashier at a grocery store. )
could anyone please point out what these

1 DPDT 5v Relay (Aromat DS2YE-S-DC5V works)
1 LM386 op-amp
1 2N3904 or PN2222 NPN Transistor
1 LED (any color)
1 1K Resistor
1 10K Resistor
1 100uF Electrolytic Capacitor

look like???

I have some old computer parts ( sound cards, video cards, floppy readers, cd readers, hard-drives) and i was wondering if i can scavenge any of these parts.

Help would be appreciated =)
REA revolution6 years ago
go to radio shack. i just asked a store clerk to help me.
In the picture above, the rectangular yellow thing directly under the battery is the relay, to the right of the relay, in order, are the LM386, the LED, the capacitor, the transistor, and the two resistors. From the picture I can't tell which resistor is which, but there are plenty of sites that can tell you how to identify resistor color codes.
plus look above :) step 2 i beleave he/she has a pic of it
google them if u want to know what they look like thats what i did
Go to if you want a better description of the components with pictures. However, the resistors will be (1k = brown black red gold) and (10k = brown black orange gold). The op-amp will have the number printed on the top as should the relay and the capacitor.
The gray band on the capacitor is the negative side (voltage in I believe) and the transistor unless someone else knows a way to determine it... well, I would just go to the Shack with Radios (Radio Shack) and know you are getting the correct component. Actually the same with the op-amp seeing as it just happens to be one of the four IC's they carry. 1.29$ and .89c I believe.
Dude, your like totally advertising that your a nerd or a geek, I get them confused, supposedly one is better than the other... Althoug, I am here... so I guess I am the pot. -J
I quit awhile ago. Now I'm a lifeguard...I save lives. ;)
REA6 years ago
will a SPDT relay work instead of a DPDT?
J-Five6 years ago
revolution Ii found all but transitter and relay
could you use a paper clip for the voltage rails?
I'm having problems finding the relay.....:(
NetReaper6 years ago
lol, it would be even better if it could surf the web for you!
arhodes186 years ago
This is so cool! I wanna try it so bad now! you should upload a video of it working. :-)
I have a big major question. Can I find LM386 op-amp like in any item? Like in a remote control or something?
Possibly, but it costs like $2.5 at radio shack
and 45 cents on electronix express
Derin chemy9996 years ago
my conclusion is rs is a ripoff the apartment with a ton of dealers is my best choice it is like the best rs ever built so cheap a ton of components only $30
weberf7 years ago
this is really cool but my mouse is 2 small and it just goes in circles but the electronics work perfectly
chemy999 weberf6 years ago
try switching the wires on the motor that is on the outside when it spins
dude,do youm know a CHEAPER version of mousebot?
the parts by themselves are only about $10 at electronix-express
it's the tools that make it expensive
My mouse has a scroller on the top. Will this block anyway of making this or will it work?
it will work
patchris7 years ago
Hello I am an inner city librarian. I love the idea of this project and would love to do this project for my kids. I followed the directions in building this mousebot, but when I flipped the toggle switch nothing happen. I left the switch on for a little bit and the battery began to get hot. What did I do wrong. Please help me.
Ianic patchris7 years ago
First off, check your connections. You could also use a breadboard to and see where you went wrong. I used the make magazine instructions. You can check your connections and such with the link below.<a rel="nofollow" href="">Make Magazine Instructions</a><br/><br/>
Ianic Ianic7 years ago
My mistake, this is the correct link

Make Magazine Instructions
chemy999 Ianic6 years ago
that link doesn't work either
koubis7 years ago
Can anyone provide the schematics of this circuit? Thanks
chemy999 koubis6 years ago
I have a major question and PLEASE answer somebody... What dc motor do I need. Do I need a 9v dc motor to go with the 9v battery? PLEASE tell me PLEASE...
the book "Absolute beginners guide to building robots" strongly recommends
a 4.7V motor
eeeXsmart6 years ago
great idea!!! =)
can u use a DPDT 12v relay instead of the 5v relay?
bassant6 years ago
hello everyone, i tried to make this robot two years ago. relay is my problem.i tried to change the circuit but it did not work.would anyone help me.
Is there a difference between the toggle switch, because theres one with 4 legs and theres one with 2 legs. I bought the 2 legged ones, but is there a difference?
Oh okay, thank you.
not really the one with four legs is just for if u need to turn on or off two things simulatiousely.
stevie17 years ago
just so every one knows theres a kit on heres the link
Ianic7 years ago
Hey I love this. I've made it, however how can I add 2 bump switches? Does anyone have a schematic for it or anything? Thanks a lot.
reon_15007 years ago
hellow sir, i want to know more bout this thing!!!
A new mouse?!?! Oh my god! Thats ridiculous! I'll just try and solder it...
I broke the legs off my IR emitters. Is there any way it will stil work?
try finding another mouse, its almost impossible to solder on wires when the pins are broken off flush
mamad8767 years ago
Hi ! I did not made this stuff but as far as I know IR Emitting Diodes designed to generate IR beam, and I wondered how you used them as sensors? Would you please explain a little more? Thanks
the silicon junction that forms the light emitting diode acts as a tiny solar cell. when light falls on it electrons are displaced from one layer and flow round the circuit to get back.
anyway to make the beetlebot a photophile? I've already made it once, and want to make it again for a school project on BEAM bots. I know it's not technically beam, but I don't have the parts to make a solar powered bot. But if I could make it find light, while keeping it simple, that would be great.
Psh, I broke off both my legs on the IR emitters. Will this still work?
How can I take off the top?
budsiskos7 years ago
i was inspired by this project and am currently working on a mousebot that uses the motors to rotate the ball in-order to move around
emoll7 years ago
i was confused by the explanation of the LM386 since both motors are connected to the same pin... am i right to think that it works because one motor has reversed polarity (in order to run forward)?
Shifrin7 years ago
Er, Any Videos?
this robot is cool
Darkshot7 years ago
yo um..could i just use speaker wire for the gauge wires?
Doveman8 years ago
Where did u find ur mouse at? Also, can a Compaq mouce work?
they have some mice at the dollar tree :) thats were i bought mine
corey c7 years ago
I made a romote controlled mouse which is by far way cooler than this project. I already made this project too does anyone have more ideas for a old computer mouse?
were you get the remote control? radio shack?
RPisces7 years ago
Is the schematic at [ THIS] link the CORRECT one??
thanks for the link :) maybe it will help me more =/
Darkshot7 years ago
ok i have a question..i saw some like portable mini fans in the dollar tree could i use those motors? cuz i dont wanna pay 2 bucks for a freakin radio shack..
ALSO!!! what else could i use for the rims besides a casset tape? i dont like to kill the 80's man :)
Strong Sad8 years ago
know what would be awesome? if you hooked up the motors to drive the origional mouseball!
ive been planning to do this for some time now its going to be remote control, and look like an ordinary mouse. (however, anyone with technical knowledge knows there isnt a wireless trackball mouse, if there is, send one to me so i can make it remote controlled
Dude, That is Exactly what I thought when I first took apart a ball mouse. An omni-directional robor that sits on your desk. if only it could dodge your hands...
kanibalas27 years ago
anyways i got a rallay that works but i have a couple ofother problems now...when i push the bump switch the relay clicks but the motors still go at full speed (actually only 1 motor goes at full speed the other goes extreamly slowly!)
kanibalas27 years ago
would a 5 pin relay work with this?
where can i find all the materials?
TO ALL THOSE WHO NEED TO TEST A RELAY OR AN IR EMMITER Even number of pins first, solder an LED to the positive lead of the nine volt battery tail, so when its plugged into a bat and you touch the other side of the LED to the other wire it lights up. Now, touch the negative lead of the bat tail to a lead on the relay, and start touching the other LED lead to the pins on the other side of the relay. When you hear a click, and the LED lights up, the two pins you have touched are the coil (drive) leads. next, try to find the pins which light the LED, but don't click, that would be the default position. there should be two pins left (if there are an even number of pins) they compose the active relay circuit (driver active) Odd number of pins. Find the coil pins. there should be three pins remaining. find the closed (default) pins, and the last pin, connected to the negative pin on the default position should circuit if the relay is closed (driver active) IR emitter use the tester above, and when the LED lights up, mark the poles of the emitter. Hope this helps!
Yes! Repost as an instructable!
RPisces7 years ago
Another thing: the right eye (facing from the front) is not working, but I think I have it connected correctly (I followed the revised schematic at the bottom of this page; some1 posted it). Help!
RPisces RPisces7 years ago
Actually, I think it just may not be as sensitive for some reason. But anyway, he keeps on constantly going in circles to the right, and not responding to light from the left. What do I do?
RPisces7 years ago
I made one of these (by the way, it looks pretty cool, too), but It has a problem. It works fine, but when you place it even on a flat surface, it does not have enough juice to move. The only thing different about it is that I did not angle the motors. Does that help the torque? I am using 2 radioshack 1.5-3V motors, but I think they may be a little weak. Any suggestions??
DarkBasit7 years ago
What's the IC and what does it look like???
its a lion7 years ago
i like it. maybe i will try to make one sometime. one question though. what are the ir sensors used for in the mouse? i know what they are used for with your design, but what are the used for in the mouse before its taken apart?
I think the ball in the mouse rolls two sets of cogs and then the ir sensors can sense how fast the cogs are going in order to move the pointer on the screen
I made a mousey too! It was a challenge to get it all in the mouse I had, but it was alot of fun. Mine is super sensitive to light, I have to be in a room without windows for it to work right. Here are the pix:
Still working on it... but GREAT project!!
stormy7 years ago
hey dose any one have a curcit digram
does it matter which momentary switch you use, or are they just both the same?
dumdog9277 years ago
where is the PCB and push switch?
Mr. Cool7 years ago
CameronSS7 years ago
I made one from the book that the Make article was taken from, but it doesn't work. When I turn it on, the relay clicks back and forth to make a little buzzer. What did I wire wrong? Also, I used an on-off-on switch with three contacts (SPDT). If I connect the outer two contacts, will that make it turn on no matter which way the switch is flipped?
Doveman7 years ago
Can i buy the IR emitters and the momentary switch? If so, where?
Renomania8 years ago
I have a few extra mice left from my old computers, but does anyone know any other fun mouse projects? My dad might throw them away if I don't use it soon. Does anyone know any PC keyboard hacks?
I'm working on something related to keyboard-hacking, may be in a few weeks I'll post it. Suffice to say that you can open it, take out the main chip, and connect wires to the terminals that were originally going to make the contacts for each of the keys. In this way you can re-make keys in a new way; for example, you can make some foot-activated keys for Enter or Escape or whatever. Note that if you connect more than one keyboard to a computer, both of them will work simultaneously. Check my page soon for details.
It would be awesome, if you removed all the keys on a keyboard. take the top half of the keyboard. and then build a disguised desk underneath, and then have the keys hooked up so that they could move in a wave pattern across the keyboard., or something like that
revolution8 years ago
could anyone please point out what these

1 DPDT 5v Relay (Aromat DS2YE-S-DC5V works)
1 LM386 op-amp
1 2N3904 or PN2222 NPN Transistor
1 LED (any color)

1 1K Resistor
1 10K Resistor
1 100uF Electrolytic Capacitor

look like???

I have some old computer parts ( sound cards, video cards, floppy readers, CD readers, old mp3's, hard-drives) and i was wondering if i can scavenge any of these parts.

I have no knowledge of electronics and was wondering what these look like

Help would be appreciated =)
All this items are cheap and easy to find, so I suggest you just buy them. In this way you'll be sure that they work, and you'll save time. Good luck.
just look it up online. If you google the name of the component it should come up. I don't think you will be able to get any of these parts from a computer...
I've gotten an LED or two from a dead gameboy, you can salvage parts from a lot of places, just be careful, LED's are polarized, They are Diodes :P
I'm just having problems finding a DPDT 5v Relay at my local Radio Shack. anyone got a weblink?
Stryker8 years ago
Little help, I finished building my "Mighty Mouse" bot but it's spinning in circles like some other people mentioned. I checked the relay with my multimeter and one motor gets +5V and the other gets -2.5V?? And to make things worse since I have been messing around with it now it goes backwards. Any help would be appreciated.
tydeus8 years ago
when you desolder, do it quickly. Research from throwies tells me that electronics can only withstand soldering heat for a few seconds before they're ruined. i would practice on just trying to remove solder or something before trying this.
Albeit slightly a late reply, but for anyone doing any desoldering components from a PCB, there is an easy way: Take some thin gauge copper wire (I use the insulating braiding from a piece of coaxial cable), and work it into a flat strip, usually 1/8" to 1/4" wide. Now the fun bit - coat the wire in solder paste, and heat so the paste "melts" into the wire. You may need to repeat this step to saturate the wire adequately. Now, to de-solder, simply place the strip of wire above the pin and heat through the copper wire (alternatively, you can heat the pin itself until the solder liquifies, then touch the copper braid to the solder) - the paste in the wire will suck the solder out of the PCB/pin. When the copper wire gets to have too much solder in it, just trim the end off, and start with a fresh piece. (Usually every couple of pins, depending on the width of your copper wire.) Sorry if this has been covered somewhere else in the site - I'm new here, but thought it might help someone out ;)
hitech4448 years ago
Help.... Mousey runs very fast. The motors are ready to explode. I measured 5.5 V on each of them. Is this correct? I used 2.0 V motors. What can I do? Please don't ask me to change them... What if I use a zener to cut the circuit voltage in half or 2 trimmer pots to cut the voltage on each motor?
Thanks for the question pal... I suggest you (and all the rest) try the following: Use 3V instead of 9V. Now your mouse won't run on steroids and even the LED on the nose will light!
i got ir emitters from a logitech ball mouse that has three legs!!!i don't understand how it would be??? how can i use that emitter in dis project..plz help me as soon as possible!!!
Slushba1328 years ago
I dont want to sound like an idiot but...What is it and What does it do?
It is a robot made out of computer mouse parts, the combination of the relay and the chip make it so that the robot will follow light (via IR emmitters) and turn when it runs into a wall (via momentary swtch). Its a fun little toy.
Poosnicles8 years ago
hey can you make a vid of it in action
Poosnicles8 years ago
hey how much does all that stuff cost about plz anwser i will make one
Hey, i have this old sound card that has a relay that looks just like the one you have on the photo, almost. I built pretty much all of mousebots guts, but my transistor broke and i found this relay and i am thinking of starting over. The relay is just like the one you have but mine says EC2-5NJ NEC JAPAN 9532 WILL THIS WORK!!!
conman4208 years ago
BIG problem. i successfully completed mousebot and everything worked fine and i can so no major problems with it except when i put it on my floor it just sat there. my wheels turn fine and i think the problem may be the back of the mouse dragging on the floor how can i over come this? Thanks.
revolution8 years ago
Is this good enough for the relay?

5-amp DPDT mini relay. Coil: 12VDC, 60mA, 200 ohm. Contact/rating: DPDT, 5A/125VAC. Size: 11mm x 19mm x 13mm. CSA approved.

heres the link:

PS: barnes, i think its from asparagus =)
it should be, if not, try and find an old fax modem. I just found one with two of the exact relays needed.
Ainshtain8 years ago
i'm a new guy here sorry for the late ...very late reply ....can i use 2 relays ...i can not finde that dam relay ....and i have 2 with 2 positions ...and 3 pins ...exept the power. So ?...OR tel me if pin 8 is conected to 9, 6 to 11 and 4 to 13 :D
grab an old fax modem. I just pulled one out of an old compaq presario and found 2 of these dpdt 5v relays on it!
lucky20068 years ago
how do you make the robot follow light. wouldn't it work just as well without?
revolution8 years ago

or refer to this link: Correct Circuit
Because of their special properties, Infrared emitters (IR emitters) are actually more sensitive when used as IR detectors than detectors themselves. Perfect for following light.
Doveman8 years ago
How many pins do the relay have to have? Where can I get a DPDT 5v Relay, and a LM386 op-amp? I can't find these at [http://http// Radioshack]<br/>
Try or Fry's Electronics (if you are lucky enough to have one around you). Radio Shack, no offense to anyone, is simply a cell phone and speaker outlet now.
Really very good...
Detonator8 years ago
At first sight of the image of mousebot I thought it was just a bunch a lousy components stuffed into a mouse. But after reading the intro i noticed that it actually reacted to the environment. Which is a cool-as robot that I enjoy making and experimenting with.
Doveman8 years ago
Where can i get all the parts, plus 2 mouses I can use??? I was also wondering, in part 3, do you take out all the circet boards?
Dragos8 years ago has been usefull. thanks. but, the problem is that there are electronics but not what i need..AUDIO AMP 1X0.33W 6V 0.2%.......AUDIO-AMP 4-12V 0,5W DIP8...
kohlious8 years ago
is this something helpful? remember i can't read the language, so don't make fun of me if it's something completely unrelated... : )
kohlious8 years ago
holy crap it actually works! it didn't work because i am apparently colorblind and i switched the resistors. wow. how neat.
Dragos8 years ago
ok, but i can't find it in some stereos or anything like that because i am from romania and it would take some time to get here
kohlious8 years ago
the site said two weeks for delivery but i swear it was at my house in like 4 days.
kohlious8 years ago
kohlious8 years ago
i made an uneducated guess when i was wiring the relay; which side is up or down. i didn't even know if it made a difference. i did it over the other way around and still no result. it is actually making that same noise it did last time around. any other ideas?
kohlious8 years ago
i have read through the comments, and it seems that noone has had this problem... my motors aren't getting any power at all! i switched the wires on them to make absolutely sure that i had positive to positive. they're new (from solarbotics) so i doubt that is a problem... the relay is definately doing... uh... something or another, the led lights up, and i can tell that the IR emitters are responsive by the different noises from the relay. what should i do? ...and could it have anything to do with overheating one of the resistors or something?
Dragos8 years ago
where i can find the relay and the LM386 op-amp.
Giz8 years ago
IR EMITTER PROBLEM: IR emitters from the Mouse and ones that I purchased at Radio Shack don't appear to be light sensitive. If I completely cover them, one of the motors shuts down and the other motor speeds up. Any thoughts? Anyone, anyone?
Giz8 years ago
Help! I have the mouse on a breadboard. When power is applied, one motor runs quite fast and is regulated when I cover one of the IR emitters. The other emitter seems to have no impact on speed. Any advice? I also have a major problem. Only 1 motor runs; when I push the bumper switch, the relay kicks in and shuts down the first motor and the second motor starts running. I have checked my circuitry and all appears well. What did I screw up?
Giz Giz8 years ago
I solved my own problem..the motors were not working properly because one of the jumpers on the breadboard was incorrectly positioned. Also, I solved the issue of the emitters by replacing them with Radio Shack emitters.
Gemologist8 years ago
Is there a slightly more complicated version that is possible to make with 4 motors, wheels?
basic8 years ago
i mean infrared emiters
basic8 years ago
were are the 1r emiters for???
Well i managed to make the mouse-bot. I had an old broken MS wireless mouse - one of the nice looking ones. It was a common problem with the mouse that the left mouse button stopped working, and i couldn’t be assed to return it so I decided to make it into a mouse bot. I had relatively no experience with soldering or similar before so the task I found really quite hard. To get two light sensors I had to take them outof an older mouse, but still used to the MS mouse shell for the robot, the MS mouse was optical so it didn’t have any where the ball would have been, but instead one where the wheel was! I got all the components from an electronics shop called Maplin, as i live in the UK we don’t have anything like radioshack. Luckily there was a man behind the components counter there that knew what he was talking about and he managed to find everything except the chip - which he got an exact equivalent of. All in all the parts cost me just over £5, plus another £4 for a cheap soldering iron to do the job. I got a proper switch for the front as the ones that come in the mouse simply aren’t up to the job. Now the building... To complete the brains of the robot in reading some of the above comments i decided to use the correct, linked above circuit diagram instead of the tutorial, so i basically didn’t really use the tutorial at all! Firstly I cut all the holes for the motor into the shell, this was hard as there are two layers on one side of the MS mouse that i had to go through. I also cut the top of the battery compartment and filed a screw placement shaft above down so that the 9V battery fits perfectly into the battery compartment on the mouse - which is a nice touch. Next I drilled a hole for the round rocker switch. The front bumper switch fitted really well on the front, i just had to remove a front plastic section on the front - there was even a small round plastic bit coming outof the spot where the front section of the mouse used to sit - this fitted like a glove into a hole already in the big front bumper switch, which could then rest against the side giving it tremendous rigidity...if that made any sense! Finally the LED and the light sensors i decided could easily come outof the hole in the top where the wheel used to be! The next task was the wiring, i started with the relay and worked out - and as apiece of advice to anyone else who is trying to make this simple robot i suggest getting a small circuit board like a breadboard as i think this would have made my life alot easier! So anyways I finished all the wiring apart from the main on/off switch and the motors. I decided to work out the correct wiring orientation for these by trial and error - the best way for it :)! In trying to get these right i discovered that the front bumper switch was incorrectly wired, and that - like other comments above, it does not work correctly. Instead for my mouse-bot at the moment it simply stops the robot, which is better than doing nothing and burning out the motors. To get the front bumper switch to do this i had to re-wire it, connecting two of the contact together as one, and the using the combined two and the third to connect the main wiring clump. I will explain a planned fix to this later on in my small novel here....this is taking longer to explain than i had hoped! Anyways I fixed the front bumper switch so that it had some functionality and now started on the on-off switch. I discovered that the two connections suggested for the on/off switch in the wiring diagram infact did absolutely nothing (i probably did something wrong here :S) so instead i left them and cut the battery connector wires and used them - that way i know no voltage is going into the circuit whilst the switch is in the off position! Finally i attached the motors, one went on the normal way up and the other needed the wires crossing unlike displayed on the circuit diagram, but by trial and error i worked out the correct formation and soldered them into place. Finally once everything was glued into the case i put it on the floor and turned it on. It went well, and appears to very slightly follow a light source. It also stops when it hits a wall, which is better than nothing! Hopefully I will submit some pictures of it at some point, I have some on another computer that I shall upload sometime....if i get round to it. Finally my idea to fix the front bumper switch. Instead of having one switch i could mount two, one to either side of the robot. As i understand it the light sensors are each more-or-less directly connected to the motors (they work by resisting the voltage into the motors therefore slowing down or speeding up each motor depending on the light level). So, if i attached a switch to each side of the robot i could then connect either side of it to the light sensor connection running straight into the motor (or the other side) - with the poles reversed. This should mean that when each switch is pressed, it make the motor on that side of the mousebot reverse until it is released, as there is one on each side of mousebot it should cause the robot to slowly twist away from the wall and move away from it! I hope that makes sense.... Let me know what you think and ask any questions if you have them, pictures coming soon!
robot8 years ago
no, it is not matter
robo8 years ago
tydeus8 years ago
they emit IR O.o actually by the picture i'm going to guess ball mouses work the same way Eintstein found the speed of light. As that gear moves the link between the two peices is broken, letting the computer know how much to move the mouse. I know nothing about electramonics...
Aeshir8 years ago
If you need spare parts you can get them for free at the Texas Instruments site (
APeiceOfPoo8 years ago
Do you think you can make a movie of it working?
nospleen9 years ago
I went to Radio Shack and bought all the parts except the relay. I also bought a socket for the op-amp. I don't know if it needed it, but it was $.69 and I figured it might save the op-amp from soldering heat. I got the relay out of a really old analog modem. 14,440 bps...must have been fast back in the day!
Yea about the relay.... i found some modems, i think they have relays on em i dunno. There are small rectangular prism boxes, black, with abot 10-12 pins on em? One says 'Delta DPSO5UO9D Made in H. K. 9803B', another says 'Bel 0027LFA 0556-3873-03' Are these relays??? PLEASE HELP MEE!! :D
Oniony is right. You probobly just found some random ICs.
Doesn't sound much like a relay to me. The kind of relays used in these projects will typically have two legs for power to drive the switch and two legs for the breakable circuit (though some have more if the switch switches between multiple circuits). The ones I've seen tend to be almost as high as they are long, a simple hollow plastic box with the coil and switch inside. Some have transparent tops whilst others are opaque. Take a look at
dont worry, daltonic electronic seller, and me to lazy to learn resistor colors ITS AlIvE!!! HaHAha aLIvE!! just need assembly PD: does anyone knows where to buy the voice activated R2D2?
please help me out :´(! i just finished my mousebot, wiring and connected to check, but it only worked perfectly for 40 sec!!! then stopped! I used the corrected diagram, and chck all the wiring and solder and resistor, they're all fine! (the only thing different is relay of 12v) I really don't get it. why it worked just some seconds?? oh, and the battery was warm im sure connections are ok. thanks for aswering
robot8 years ago
i ask :-) (post picutre)
mstrauss8 years ago
Finished my mousebot yesterday...working great, and looks just like a little mouse! Though it needs a fresh battery to go from reverse to forward drive consistently. Features include cute paperclip whisker-bumpers, flames on the sides, 2 LEDs for eyes, photodetectors tucked under mousey ears, and adjustable motor drive potentiometer accesible through ball hole in bottom. Will post pictures if anyone asks.
robotix8 years ago
Why do you need a floppy?
oniony robotix8 years ago
"1 CD-ROM or Floppy Disk (for the bumper)"
oniony8 years ago
"1 CD-ROM or Floppy Disk (for the bumper)"
m_jake (author) 8 years ago
@Aggie86: Your Relay - DS2Y 1 - 1 2 - 4 3 - 6 4 - 8 5 - N/A 6 - N/A 7 - 9 8 - 11 9 - 13 10 - 16
removed38 years ago
I have seen this in another site
Aggie868 years ago
Hey Guys,
GREAT IDEA and really good information from all of you on how best to complete. My 9 yr old son is really excited to build his first ROBOT. We have perfomed the neccessary operations on our Donor Mouse and are just about ready to begin the soldering...we've run into a problem. Ordered the 5v relay online and the pin layout does not match the one used in the schematic/directions above...I found our actual chip (NAIS TQ2-L-5v) layout online here: but not sure how to proceed. Anyone got the time to help a Dad in over his head??
Thanks in advance,
robotix8 years ago
robotix8 years ago
Oh I see it's the LM386 op-amp.
robotix8 years ago
Where did the chip come from?
robotix8 years ago
What do the IR emiters do?
robotix8 years ago
spyker32928 years ago
I just finished mine works pretty good but the bump switch is broken i kinda accidently pried it apart
Prometheus8 years ago
I gotta say this is really cute, gonna build one sometime. For those having trouble with different motor speeds (saw it up there somewhere), make sure you are using two matched motors, anfd that one is not binding. Assuming you already checked for that, you can use very-low resitance resistors or even an inductor to tune the motors to match. You can even use a an adjustable ceramic-wafer resistor salvaged from the kine socket (tube socket) at the rear of the picture tube, or from elsewhere. Be sure it can handle at least 2.5 watts....
techie8 years ago
I had the same problem with the mousebot going in circles. I tried reversing the "eyes" from the way I thought they should go ( + instead of -). Perhaps I just didn't understand my multimeter. Now it runs correctly, except that one eye seems to respond to light, but the other doesn't. It helped to take it out in the sun and cover one eye and then the other, watching the motors change speed. I may try replacing the eye sensor that's not responding.
debugger8 years ago
u should make a diagram of all the points that canect cause i cant see them in the picture plz
robot8 years ago
i have same problem like backcountry and LF_27. backcountry - can you put ciriut diagram here (for IR and trimpot), please.
spyker32928 years ago
I just started making mine, I hope it works when I'm done. I'm just waiting for a relay to come in the mail, 5V relays are hard to find.
LF_278 years ago
Hi Backcountry, thanks for the reply. Just one clarification. One motor runs way fast then the other, regardless of the light around. Your suggestiion addresses the light sensitivity only. any other ideas...
backcountry8 years ago
My mousebot tended to go in circles too, especially under low light. To balance out the 2 sides, I added a trimpot between the photodector 'eyes'. Hook one side of the trimpot to each side of the photodector that connects to the LM386. Connect the wiper to the photodetector sides that are joined together. I used a 100K trimpot which is way too sensitive, a lower value would be easier to work with. Determine the correct trimpot setting (how much R goes to each side) by trial and error. Tweak, test, tweak, test...
LF_278 years ago
hello, there seems to be a problem with my mousebot one motor goes way faster then the other andthis makes the mousebot go in circles. does anyone have a solution?
your butt9 years ago
I am new at robotics and I want to build a Sumobot. I feel like an idiot writing this but I was wondering if there were some way to modify it so that instead of retreating when it hits the wall (or an enemy bot) it would push harder
Are you talking about the Parallax, Inc. Sumobot kit? If so, it should have a chip that you have to program. You can change the program around to make it do whatever you want. I have a Boe-Bot and I program it to do all sorts of things.
santo679 years ago
I've got this thing put together, but the light doesn't seem to be having an effect on the power delivered to the motors. Radio Shack, as many here have discovered, does not carry the 5v DPDT. So, I got two SPDT, and attempted to make one DPDT out of them by wiring the coils together in parallel. Should this work?
Mr. Cool9 years ago
Drive around.
SirMorris9 years ago
Hi there! I'm about to start construction of mousey #1. I've scavenged & hunted all the required components. Last night I thought I'd test out the photodiodes that I ripped from a donor mouse. One of them seems to produce more juice than the other. As there's no trimming components in this simple circuit, will this be a problem? In anticipation, Charlie
backcountry9 years ago
This project looks really cool - similar to the Cybugs at I'm wondering if there is a relatively easy mod to the circuit possible that would make the mouse stop moving when it finds the brightest spot it can. And then start moving again only when it sees an even brighter spot. The theory I think would be that the rate of motion is proportional to the difference in light reception between the two eyes. When the two eyes see equally bright light, the mouse stops. When one eye sees higher light, the mouse turns and moves in that direction. Is such a mod possible? Easy to explain? Thanks again for posting this project!
TheDon9 years ago
ok, the first two questions helped. But i got my relay from an electronics manufacureer in montreal, and on the underside of the relay there are no numbers like you said. 3456 10987 thats what i see on the underside. Also, two of the pins are spaced away from the rest of them. Can i assume that they are pins "1" and "16" respectively like in your picture above?
nospleen9 years ago
I don't think the voltage of the capacitor matters, but I used a 35 VDC 100 uF capacitor. Also, it has a negative marker on it. Mine was just a black stripe with negative symbols above the negative lead. I don't know of any other way to test the leads on the IR without using a multimeter. If you don't have one you can pick one up for $20 or so at RadioShack or any other electronics or even hardware store (HomeDepot...). The underside of the relay has small numbers on it next to the pins. They should be numbered 1-8....
TheDon9 years ago
And also, how can you tell which pins on the relay are the right ones?
TheDon9 years ago
Question, I know that the capacitor to be used is 100uF, but there are so many types with different voltage. How do i know which one to use? And also, how do i know which side is the positive side and which is the negative side. One more thing. Is it possible to tell which side of the IR emitter is + and which is - WITHOUT using a multimeter?
elise9 years ago
i think you might have one of your motors hooked up backwards. i had the same problem and then realized i had the ground and the lead on the non-working motor switched. once i corrected this, the two motors worked in tandem. and the mousebot moved in a line.
kejbja9 years ago
My mouse just goes in a circle.I use the schematic from
I made a different mouse with all new and different parts and it still goes in circles.
Any words of advice?
m_jake (author) 9 years ago
Its hard to tell exactly where the problem could be, I would suggest going over the schematic and your wiring and then going over it again. Make sure nothing is shorted and everything is connected properly and in accordance with the schematic. If you still cant get it to work try replacing the ir emitters, one could be burned out, if _that_ doesnt work it could be the op amp but it is not very likely. Good luck, later.
athlon8869 years ago
To add to my last comment... I tryed a different motor on the side with the weak motor and it was still slower than the left motor... I think it would be something to do with the right side also being wired to the op-amp and realy? or no? Please help.
athlon8869 years ago
Ok.. Slight problem. Everything is done... but one wheel is spinning faster than the other lol. so it just does dougnuts... How can I slow the other down? Thanks, Collin.
ken9 years ago
The slightly longer lead on the led is the positive one. The resister should be connected to the positive lead.
athlon8859 years ago
How can I tell which is positive and which is negative on the led? or does it matter?
kenh9 years ago
Need more information on the relay. I bought a Aromat/NAIS TF2-5V (ATF209) DPDT relay. It has 10 pins numbered + 1 2 3 4 5 on one side and - 10 9 8 7 6 on the other side. How does this correspond to the 8 pin Aromat DS2YE-S-DC5V relay? It would help to compare schematics...
ken9 years ago
Is there any reason why the motors must be installed at a 60 degree angle, other than to ensure that the wheels touch the ground? I'm thinking of installing them at a lesser angle and just using bigger wheels. Tilting the motors less gives them more room to fit inside the mouse case.
athlon8859 years ago
Ok, I find the corrected diagram hard to follow so I was wondering, if you just used the diagrams above with out correcting the LED circutry would everything run, except the led?
It would all run...just not correctly... I shall help you with the circuit, don't be discouraged by the diagram, if you break it down you can figure it out. So, instead of connecting the lead of the resistor to the led, and the led negative to the IR sensors; connect the positive lead (anode) of the led, the resistor, and the negative leads of the two IR sensors together. That will make a connection of four leads. The only other thing that changes is the negative lead (cathode) of the led connects to the negative terminal of the battery, so find all of the wires to negative (from pin 9 of relay, transistor, and pin 4 of op-amp) and connect it with those. Those are the only changes to the circuit! Good luck. And I realize it can be confusing, so don't hesitate to ask any more questions! Thats what we are here for.
gotto_metka9 years ago
where can i find the alternate RELAY. is that availlble in the electronic store
gotto_metka9 years ago
where can i find the alternate RELAY. is that availlble is the electronic store
athlon8859 years ago
Ok, I found the notch... thanks for that. I am having a problem with finding a relay though. I ordered one and then the people waited a week to tell me it was on back order, which was bad because the project is due on the 9th. Anyway, Ive takin alot of stuff apart and only came accross one relay in a fax machine. Here is what it says on the top: Omron G5V-2 24VDC Then on the side it says: 0.6A125VAC 0.6A110VDC 2A 30VDC 1565 KG4 Will this relay work? Will it still operate? Ive been told that if I used a relay that was higher than the 5V I needed it will work just switch slower... Is this true? Thnaks, Collin.
The ratings are fairly close to what are on the relay that I used. Yours are just twice the amps. As long as the relay has 8 pins I imagine that it would work. I would try it and see how the circuit responds with that relay. If you have a breadboard I would wire it in that first to test it, that way you dont have to mess with soldering. Hey, it never hurts just to try things.
athlon8859 years ago
On the bottom of the LM386 Op-AMP how can I tell which side to short the two pins on? There are no numbers to tell me which is pin1 ect...
On one end of the chip there should be a little notch that looks like a semi-circle. With the top of the chip up, the pins are numbered 1-8 counterclockwise starting at the top left (with the notch at the top).
Hopefully that was somewhat understandable.

That would mean that the two pins two short are the pins next to the notch.

If you go to there is a good schematic that shows the layout of the pins on the chip.
fluff9 years ago
I just finished putting my new and beloved mousey together and I've got a stupid problem. I think I got all the parts right. resistors are ok due to my meter; the relay switches upon pressing the backup switch. The capacitor seems to be ok since the relay switches back after about 3-4 secs. The only problem is the voltage to the motors. One motor gets the full power; the other one gets almost nothing. This inverts once the relay switches. Might this be due to a defect in the LM386? Might be that I overheated it during soldering? Or could it be that I've got the wrong transistor?
nospleen fluff9 years ago
Ya, I would think it has to do with the op-amp. I had I similar problem but found that I had connected a wrong pin the negative lead on the battery. It was fixed as soon as I connected it to the correct pin. I used a socket for my chip to prevent overheating. I picked them up at radio shack, two for 69 cents. Not too bad. Then I just soldered that as I would have the chip, and popped in the actual chip when I was done.
fluff9 years ago
By this I mean that the difference in voltage inverts (now the other motor gets more power) once the relay switches.
m_jake (author) 9 years ago
fluff: Its hard to tell exactly but what I would suggest doing is holding the gnd lead of your muli-meter on a grounded connection then following the motor connections backwards to see where the difference first occurs. Another thing to try would be to de-solder the IR emitters and switch them and see if the other motor gets the low voltage, excessive heat can probably damage the emitters more easily than the 386. What exactly do you mean by "This inverts once the relay switches"? athlon: yup, the right if the bump is facing up.
athlon8859 years ago
Hey.. I have the same emitter.... With the three pins. So I understand that I connect the plus lead to the middle pin... and the gnd on the right? just making sure. Thanks.
ken9 years ago
I've completed the mouse autopsy and harvested the infrared emitters. Mine have three contact stubs, not two. How do I know which ones to hook up? I'm prepping the body and have ordered a relay, so hopefully I'll be building in earnest soon. Thanks
m_jake (author)  ken9 years ago
I found some of those three pin ir emitters in an old Radio Shack mouse once. these emitters are basically two in one package they can work by connecting the gnd pin in the middle and the + on the left (if the bump is facing up), alternatively you can connect the plus in the middle and the gnd on the right. The pins are ordered like this: (+) | (v0) | (-) | where each "|" is a pin. Thats how the theory goes anyways... I havent used any of these emitters myself so let me know how it turns out. Later.
athlon8859 years ago
Thanks, this site is a real help.... I will post pictures when I am done and tell you how I did.
athlon8859 years ago
Hey, This is Athlon884..... lost my old password. Anyway, I got two motors out of an old CD-Rom drive, theyre a little bigger but i can make room. I tested them and they ran at a fine speed on the 9V battery. My father brought a box of old electronics from his store to take apart, I found the LM386N on an old modem, some led's, and plenty of resistors. I also found the capacitor on an old stero (100uF) but wondered if the voltage mattered? It says on it 100uF 16V... Does it make a difference? Also Ive been told the 1k resistor is Brown, Black and Red.... What color is the 10k resistor? Ive ordered the rest of the parts (Switch, Relay etc.) from an electronics store. Thanks, Collin. (Will post pics of finished product)
m_jake (author)  athlon8859 years ago
yup, brown black orange is 10k and for the capacitor 16v should be fine, as a matter of fact im pretty sure thats what I used.
The 10k resistor is Brown-Black-Orange.
ken9 years ago
Athlon884 - Go to to see the correction to the LED wiring. It's at the bottom of the page under "known bugs, issues, and troubleshoots. As for the motors,you can use 1.5-3VDC motors available at Radio Shack. I have the 273-258 metal gear motor that costs about $3.00.

ken9 years ago
Hecbot - thanks for your reassuring response. Let me respond in kind by assuring you that the true function of the LED in this project is not to light up, but to serve as a booster for the sensitivity of the infra-red emitter eyes. I've read this in several places. While the LED may light up initially, that is not its purpose here, and it should not be of concern if it does not light up at all or eventually goes out-- it's still apparently fulfilling its destiny for mousey. While we're on a roll here, any suggestions for an easy way of finding the double pole double throw 5V relay? Radio shack doesn't carry it. I'm looking around for an old modem or answering maching which I understand have such relays, but they don't seem to be easy to come by.
moochman169 years ago
Hello, I built the mousebot and everything is working great except for one thing, the bump switch. I followed all the steps but when my mousebot bumbs into a wall, it doesn't move. Can you help me? Thanks, Stephen
waht does it do anyways but it looks cool
hecbot9 years ago
Ken, I'm using the Radio Shack LM386N 400mW part 276-1731 and so far it is working well in conjunction with my mousey "eyes" and a light source, at least on the breadboard as per the Make article. I'm now about to lay out my parts in the mouse (hopefully everything will fit). Got a question about the LED -- is it supposed to light up? Mine isn't lighting up, but then again maybe I'm being the newbie that I am. Mousey is my second project; Cmoy headphone amp was my first. Will post pics when I'm done. Thanks to Gareth and Jacob -- this is a blast!
ken9 years ago
I'm collecting the parts for my own mousey. Read the book, the streettech corrections to the circuit, and this article, which is very helpful, particularly the photos. But tell me, do you know if Radio Shack part LM386N (400mW) Audo Amplifier is the same IC as the LM386 used in Mousey? This one is an 8-pin DIP, but it doesn't say Op-Amp anywhere, and my research hasn't made it clear whether there's a difference between an op-amp and an amplifier. Thanks, and congrats on your completed project.
m_jake (author) 9 years ago
Howdy. Gareth is right about the LED wiring (he's the one who wrote the article in Make). The revised wiring diagram is here: The motors should be somewhere around 4.5v with a range of maybe +- 1v so most any regular small hobby motor will work, just make sure its small enough to fit in your mouse. Later
athlon8849 years ago
If its not too much I have another question. What voltage are the two DC motors? Thanks
athlon8849 years ago
Hello... Is "garethbranwyn" right about the LED wiring? I went to the site and couldn't find anything relating to what he said. I am going to do this for a school science fair and want to know how I know when looking at the relay to tell which side is which? (Where is Pin1 ect... comparing to the front side of the relay?) Thanks, Collin. Please reply asap as project is due by march 9th Thanks.
catcher289 years ago
is it realy that cheep? I like robots but i'm not that into it.
Awesome job, Jacob! Readers/builders of this project should be aware of the fact that the wiring for the LED light sensor sensitivity subcircuit, as detailed in the Make article, in my book Absolute Beginner's Guide to Building Robots, AND in Dave Hrynkiw's Junkbots book, is incorrect. You can find the corrected circuit diagram on my book support microsite on my site