Introduction: Simple Bots: Walker

Picture of Simple Bots: Walker

My goal with Walker Bot was to make a 4-legged walking bot that could be made in ten minutes. This bot ultimately took me three hours to make. That said, my goal wasn't to make one in ten minutes, but to make one that could be made in ten minutes. I am pretty confident that now that I know what I am doing, should I need to make a second one, I could do it in ten minutes. At the very least, you will be hard-pressed to make a simpler walking bot than this one. I would consider this project a glowing success.

Step 1: Go Get Stuff

Picture of Go Get Stuff

You will need:

(x2) servos modified for direct drive**
(x1) telephone handset
(x1) 4 x AA battery holder
(x1) DPDT lever switch
(x2) CDs
(x2) 6" bolts
(x2) 5" bolts
(x4) bolts
(x4) bolt covers
(x2) thin 1" nut and bolt
(x1) a couple dozen assorted zip ties
(x1) print template (download below)

**Modify your servos for direct drive here

Step 2: Open It Up

Picture of Open It Up

Remove the covers from the telephone handset and pull out the speaker, microphone and jack. These should come right out.

Step 3: Drill

Picture of Drill

Drill 4 holes in each end of the telephone handset as pictured.

Essentially, you should drill the holes in such a way that they create a square on the backside of each opening.

Step 4: The First Motor

Picture of The First Motor

Starting on the side of the handset opposite where the jack was, pass the motor's wires through the body of the phone and out the hole created by removing the jack.

Insert the first motor into the handset opening that is on the opposite side of the jack, in such a way that the horn is facing inwards.

(The horn is the gear-like object attached to the servo shaft)

Step 5: The Second Motor

Picture of The Second Motor

Pass the second motor's wires through the hole created by the jack and insert that motor into the end of the handset. Make certain that the horn for this motor is also facing inwards, as well.

Zip tie them both in place using the holes that you have drilled in Step 3.

Step 6: Switch

Picture of Switch

Zip tie the DPDT switch to the round mouthpiece opening, right above the hole created by removing the jack.

There should probably a small lip, upon which the switch can sit.

Make certain that the lever of the switch is pointing upwards (towards the gear on the motor).

Step 7: Template

Picture of Template

If you have not done so already, download and print out the template file.

Cut out around the circumference of the two large circles.

Step 8: Cut the CDs

Picture of Cut the CDs

Tape the templates to the center of each CD.

For the two large outer holes, drill 1/4" holes (or whatever is appropriate for your 5" and 6" bolts).

For the four smaller inner holes, drill 1/8" holes (or whatever is appropriate for your thinnest zip ties).

On the one CD with the outer notch, cut this shape out of the CD using a pair of general-purpose scissors.

Step 9: Battery Holder

Picture of Battery Holder

Drill two 1/8" holes into the center of the handset such that they line up with the mounting holes of your AA battery holder.

Bolt the battery holder onto the handset with your pair of 1" nuts and bolts.

Step 10: Wire It Up

Picture of Wire It Up

Solder the red and black wires from the battery holder to each of the center terminals of the DPDT switch.

Solder two short wires such that an "X" is formed between the outer terminals of the switch. Basically, the back left would be connected to the front right and the front left to the back right. This causes power to be applied backwards when the switch is flipped.

Solder together the red wire from motor 1 with the black wire from motor 2 and the black from motor 1 with the red from motor 2 (which motor is designated to be which is unimportant).

Lastly, solder the red and black wire pairs to either set of outer terminals. For instance, solder one pair to the back left terminal and the other pair to the back right terminal.

If all of this sounds really confusing, just check the wiring diagram below.

Step 11: Attach CDs

Picture of Attach CDs

If necessary, make or widen holes in the servo horn with a 1/8" drill bit to accommodate the zip tie.

Zip tie the CDs to the motors in such a way that the motor is at the center of its rotation point and the two outer holes are perpendicular to the handset.

Also, keep in mind that the outer notch was cut to allow the switch lever to stick through.

Step 12: Bolt

Picture of Bolt

Pass the shorter bolts through the notched CD, towards the body of the phone.

Pass the longer bolts through the other CD.

Fasten all of them in place with nuts.

Step 13: Bolt Covers

Picture of Bolt Covers

Cover all of the bolts with rubber bolt covers to give them a bit more traction.

Step 14: Power!

Picture of Power!

Center the CDs such that the bolts are perpendicular to the body of the phone.

Insert batteries, and then let it go.


jvmuser1 made it! (author)2016-11-11

I know im a few years behind here but cool remains cool....and this is most certainly cool.....a very very simple and very clever idea.....a mechanical robot and not electronic ..I think you may be a genius....thank you.if i use dc motor instead of this motor?

it is right to do.

Because when you remove controller from motor it will move continuously and dc motor is also moves continuously. A dancing robot.

afridave (author)2016-07-04

I know im a few years behind here but cool remains cool....and this is most certainly cool.....a very very simple and very clever idea.....a mechanical robot and not electronic ..I think you may be a genius....thank you.

killerg (author)2016-04-27


zeeshan_work (author)2015-04-29

if i use dc motor instead of this motor?

it is right to do.

Because when you remove controller from motor it will move continuously and dc motor is also moves continuously.

randofo (author)zeeshan_work2015-05-05

It would have to be a geared DC motor. A DC motor by itself probably won't have enough torque.

misbah25 (author)2014-12-07

i have a 3 pin dpdt lever switch there any way i can use it ???

randofo (author)misbah252015-05-05

Nope. This wont be able to reverse the voltage.

misbah25 (author)2014-12-07

my dpdt lever swich has only 3 pins instead of 6 like yours ? is there any way i can still use it ? im doing this for my school project and im in a hurry....pls reply asap

M.C. Langer made it! (author)2014-10-02

I never post the "I made it" of this bot. I love so much this project!

robobot3112 (author)2014-08-23

what sets of the dpdt?

Sai Sathvic (author)2014-01-14

hey admin how did u do the servos for direct drive can u explain me properly i can't understand the way wat u said?!

Graut (author)2013-10-25

Nice Robot, but I have a question regarding the servos motor.
I have modified it like said in the walkthrough, but my motor goes just one way, it doesn't go forth and back like it should? I haven't used a DPDT switch, because it is damn hard to find, so have just used a regular switch, is this the problem? I can get 2 SPDT switch, so maybe I have to try that...
Thanks in advance

Graut (author)Graut2013-10-27

I have now tried the 2 SPDT switches, and gotten the motor to go back and forth...but I have to press the switch every time I want to switch the way the motor goes. In the video the motor goes back and forth without pressing the switch, is that because of the switch I have used or have I done some other thing wrong?

mArtiAnOk (author)2013-03-28

does the CD toggles the lever switch?

randofo (author)mArtiAnOk2013-03-29


jvega7 (author)2012-09-01

thank you for join it, now i am motivated for build it..

mahsa arian (author)2012-09-01

its so amazing
i follow your great idea. thanks for share it :-)

rohit007 (author)2010-09-07

awesome man...!! really..wrked..nd dat too on my first try..thnx..i ll remeber dis bot....forever !!

shivam dehinwal (author)rohit0072011-02-01

hey ! its shivam from delhi and i am also trying to make this one........but i cant find the servo motors as well as the DPDT lever switch........can u tell me from where did you find it?????????

i got one from an old rc toy. hope this helps and goodluck!

dannystaple (author)simplebotics2012-08-19

You will find servo's on ebay fairly regularly now - but old RC toys are also a good source.

chaitanyak (author)2012-08-16

elegant mechanism :)

superstatic27 (author)2012-07-13

I'm a bit confused. So because it's a DPDT switch wired to run backwards also, you don't use the switch to turn it off but to reverse the motion? Would the only way to turn it off be to take the batteries out?

randofo (author)superstatic272012-07-13

Yes. The only way to turn it off is to remove the batteries.

The DPDT switch reverses the polarity of the power going to the motor. When the polarity is oriented one way (+ to -) the motor spins in one direction. When it is reversed (- to +) the motor spins in an opposite direction. The bot is basically changing its own motor direction.

mraghib (author)2012-04-07

Nice & innovative idea!Can you please tell me can we use toy motors instead of servos as they are expensive! Thank You!

randofo (author)mraghib2012-04-07

Yes. Just get 2 identical geared motors.

mraghib (author)randofo2012-04-07

Is a toy motor and gear motor the same? Sorry I'm new to robotics!

mistu99 (author)2012-02-13

can u reply quickly because i need 4 Wednesday

mistu99 (author)2012-02-13

can i use a motor to replace the servo because in uae i can't find it

jualone (author)2011-09-27

very weel

sofsof (author)2011-06-20

that is so cooooooooooooooooool
i like it very muuuuuuuuuuuuuuch

anubhavtalukdar007 (author)2011-06-04

Continue giving us more instructables...........

Soon. Very soon.

ptrinidad (author)2011-06-04

very good man!!!

sajee (author)2011-03-09

my servo has 3 wires and how can i convert them into 2 wires like seen in the pictures

robotics_sk (author)2011-03-06

hi, does it matter if instead of a standard servo we used a continuos rotation one?

randofo (author)robotics_sk2011-03-07

That should be fine.

robotics_sk (author)2011-03-05

how do i print the templates?

randofo (author)robotics_sk2011-03-05

You should be able to open the eps with one of the image viewing programs on your computer. Then, just print it out using a normal computer printer (be careful not to re-size it)

robotics_sk (author)2011-03-02

where can we buy the servos motors??

randofo (author)robotics_sk2011-03-02

I'm using Parallax motors. Try:

101nemesis (author)2011-02-19

the thing is if we modify the servos for direct drive.
wont it block the handle of the telephone.?

randofo (author)101nemesis2011-02-20

What do you mean?

101nemesis (author)randofo2011-02-21

no what i mean is ..
wont the bolts get hit by the arm of the telephone..
and could u pls tell me how does a modified servo work ..
as in how does it rotate exactly
thnk u

randofo (author)101nemesis2011-02-21

No, because the switch reverses the movement of the motor before it gets the chance to go that far.

Basically, a servo is a geared motor with a controller board inside. When I modify it, I remove the controller board so that the motor becomes direct drive. In the materials step, I have a link to how to do this.

101nemesis (author)randofo2011-02-25

thanks a lot for your help..
can u pass me the link cause i tried modifying and it was a great flop...

Bj14 (author)2011-02-07

Which type of servo motors are used here?
Can we use simple dc motors used in DVD,VCDs ?

shivam dehinwal (author)Bj142011-02-14

u can use the one found in the air can it from an A/C service centre.........hope this helps.......

simplebotics (author)2011-02-04

i was wondering could i glue two SPDT lever switches together and that means it will have 6 total leads and the cd can still press switch both ways? PLEASE HELP! thanks :) !

randofo (author)simplebotics2011-02-04

Yes, but it won't be as reliable. You would to carefully position them so they are both hit at once or you might risk shorting the circuit frequently. You should try to get a DPDT switch

About This Instructable




Bio: My name is Randy and I founded the Instructables Design Studio. I'm also the author of the books 'Simple Bots,' and '62 Projects to ... More »
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