Picture of How to build the one motor walker!
2 version one motor walker.jpg

Here is Instructables on how to build a walker with only one motor! This design is base
on the principal of B.E.A.M robotics! Building simple and elegant robot inspired by insect.
This robot was build back in 2000 and want to show you how to build it.

Beware this is a complex project!

This project incorporate two more instructables
How to modify a servo motors.
How to make the bicore circuit.
( I still did not learn with those truncated title :P )

Here are the 3 most important steps in this Instructables

step 1 - Read carefully!
step 2 - Read again before asking questions, check the comments!
step 3 - Did you read? if not goto step 1

PS- My instructables don't even contain a lot of text! Just pictures! :)

To be able to make this robot you need skills.
You will need to solder electronics components.

Gareth Branwyn once contacted me to make a article in his book about my one motor walker.
The chapter is online. This is worth reading in parallel while making the robot.

Solarbotics made your life easy by making custom bundle for you!
I don't think there is a big gear is in there. Be careful.

If you never build a robot and want to tackle the one motor walker, I suggest you try the beetle robot.

Good luck!


Don't forget to check my website to see my latest projects!

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mametchi3 months ago


hi robomaniac can u plz. explain me the working of bicore used
can it move in all direction
Can we get the gear in a sewing machine???????
My mother's one has failed.....................
james0093 years ago
really interesting...
oldmechanic3 years ago
Amazing, if you could fit a camera and remote control, cool!
Gliucoza6 years ago
does it has sensors?
robomaniac (author)  Gliucoza6 years ago
nope, it does not have any sensor. It can not backup. I am working on a other version that could turn and seek light.
hello jerome , ummm.. there is a problem in my circuit the motor oscilates more on one side than the other i checked everything but nothing was wrong in the circuit any idea why ?
robomaniac (author)  sid_bet6 years ago
hello, that is normal due to the fact that it is a bicore. Mine does the same thing. That is why I have a mechanical stopper ( the nail ). You can change one capacitor and try again. You could try to change both cap. Thanks Jerome
robomaniac (author)  sid_bet6 years ago
cool! Thanks
hello jerome , I took some pics of rahil - the one motor walker
 Hello sid..
well i liked ur robot.
Also i have the same problem as u have that it tends to rotate to one side more than the other.
so how did u manage to make it almost perfect synchronism.
 hello ,
           I think you might as well check for capacitor connections you cannot get it perfectly stable so the best idea is to uses a spring or rubber band as jerome told .i found that it really helps. also found that a little left or right movement doesn't affect much of the walking gate. you can use a nail or a paperclip to stop excess movement most beam bots have these springs attached to them both my robots use a spring mechanism the last picture is of mark tilden's famous spyder which also has the springs built in. to give suspension and a controlled step
The bottom pics are AWESOME!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
hello again jerome , i came to know that these bicores can be hooked to one another to make master/slave bicore pairs for a two motor walker problem being that they also go out of syncronisation .is their any way to fix it .also do microcores have the same problem
robomaniac (author)  sid_bet6 years ago
I like your robot! Microcore circuit then to do the same thing. You will see that every BEAM walker have this sort of spring or mechanical stoper to prevent the legs to make a full circle. Even go perfect circuit will then to make a full circle after a while. The best solution is a spring so it looks more natural ans smooth. If you build a microre citcuit you will need a motor driver because you can not connect motor directly to the 74AC14 chip, to much current. have fun. Jerome
hey i hav made a light following robot. :)
hello jerome ,
                        Can i add another gear at the front to give it an extra pair of legs . will the torque over the gear decrease even if i keep the gear ratio 1:1 ?
i heard that u have made a better version , will it be coming here ? please post a photo of it .
eagle inam3 years ago
ethiran3 years ago
I think it could be nice to be a striderbot but it is heavy.so awesome!
edwinzea3 years ago
Hey Robomaniac, thanks a lot for all the info and tutorials. I built my first one motor walker based on yours http://letsmakerobots.com/node/30546

fernando 13 years ago
massa vei eu queria fazer u desse :-)
xarad4 years ago
really cool!!! :-)
I think this is so cool
rsharma-54 years ago
Hello...i'm Rohit...
can you please tell me where can i find a bicore circuit...
101nemesis4 years ago
can sombody tell me where i can get thes 2 inch gear..
checked many shops cldnt get it..
is it available in any toy which i can dismantle and take from.
you can get lego gears or i would just go to some garage sales and try to scavange some from old junk :)
i have made the bicore and then connected it to the motor..
and powered it but the motor is still rottatting in 1 direction..
is it supposed to be like this or..
does the bicore automaticaly after certain rotation change the direction of the motor to opposite direction..
thank you...
what exxactly is the role of bicore....
the role of the bicore is to make the motor(s) oscillate to make the legs move back and forth in a walking movement. i would double check the schematic and pictures/instructinos, hope this helps and if any more trouble just comment again and i will help till you get it right :) !
101nemesis4 years ago
hey guys.
i got the ic 74hct240.
What i was wondering is that does this ic require any sort of programming or is it pre programed..
no, you do not have to program the ic it is what it is, just use the capacitors, resistors, pin sockets, and the ic to build the bicore. thanks and if you like simple robots and beam robots check out my blog at www.simplebotics.blogspot.com :) ! 
thanks alot !!
I checked your blog out !! Models look amazing !!
thanks fr your help again !! :)
no problem :D !
hey do we have to modify the servo motor for continous rotation for this walker...?
yes you do :)
but what i dont get it is..
if we see the video it goes both clockwise nd anti..
but if we modify wont it give continous..???
the battires look like cannons. it cousld be a turret with a little modifycation
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