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.
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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

davejuniortwo7 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?
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