Let's Make Robots!

BoB v1

walks around

The original BoB the bipded robot. 

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8/26/13- BoB has an article on maker! http://makezine.com/2013/08/25/build-your-own-biped-robot/ thank you ignoblegnome

Also if anyone would like their BoB displayed at my table at maker let me know and we can set something up i think it would be really cool to show the bobs from around the globe

june 26,2013: working with oss to get some feet with more space for a battery pack made to free up some head room. also if anyone with a bob could send pictures to my email kev.biagini@gmail.com so i can add them to the "bobs of the world" page on instructrables it would be appreciated. stay tuned for feet updates pics and such here https://www.dropbox.com/sh/jf1k61dickb37up/8jH1Nsmho_

for those that have to have the latest i work from my dropbox and i will share with you


BoB on the web. as i find links i will post them..feel free to let me know where you have seen him!



Update:now an instructable! http://www.instructables.com/id/BoB-the-BiPed/ 

the response from instructables has been amazing he is closing in on 20K! views. 190 favorited him. instructables even used him in the new toy contest banner. and the support from you all has been aamazing. THANK YOU. all of you. please help BoB continue his journey to world domination! share the link and vote. THANK YOU


this is BoB, my version of the 4 dof mini biped.


his goal in life is to walk around and take over the world one 3d printer at a time.

at this time the 1st prototype is under construction. the plans are to use a ping for vision, dagu mini driver for a brain, and 4 9g micro servos to shuffle around.

my real goal with this is to see people build and release their own bobs and make their own add ons.

a link to bobs thingiverse:



3d assembly made in solidworks 2010

awesome 3d parts thanks to mr. FrankNeon

Bob's first add on. 


more to come when i get the 3d parts in the mail.



got the package yesterday and got him together last night. i did need to sand the servo spots a bit to get the servos in but it has resulted in a screw free fit. same witht he ping in his head.


VIDEO HERE! (cant embed photobucket)


version 1.2



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Creepy BoB...

Cool! How did the LEDs fit?

I had to ream the holes out a tad but that's probably my bad print. The spacing was also off from the protoboard which required some fidgeting.

Need multiplexing!

Is it my imagination or does the orange bot remind you of the Instructable robot?

i thought the same think..was even considering making a design file for a 3d intructabot.

I was watching Chris's video of the robot walking. If you use the accelerometer in the Micro Magician for feedback on the servo speeds then I think you could get a smoother walking action and prevent accidentally falling over.

For example, let's say he needs to tilt the body by 20° to lift his foot. Rather than using a timer to control servos speed, use his current body angle so that as he aproaches the 20° mark, the servos speed slows down.

If you can get the servos working to a sin wave pattern then that would produce the best results. You should be able to get a smooth pendulum motion going.  If you control the twisting motion of the feet in the same way then the feet should get much better traction because the servos won't jerk, causing the foot to slip.


Could you not just use a PID Loop instead of using an accellorometer? Here is a code example:

int error = 0;

int wait = 0;

const double k = 8.2; //value would needed to be tweaked depending on needs


//current is less than target

if(current < target)


for(int i = current; i <= target; i++)


//PID algorithm

error = abs(target - i);

wait = abs(k/error);



//update the servo





//target is less than current



for(int i = current; i >= target; i--)


//PID algorithm

error = abs(i - target);

wait = abs(k/error);



//update the servo





The code example might not be perfect but it should give the generally idea i am trying to convey. I must say that I am a big fan of accelorometers though, but I also like to have options, and I am sure others do as well! This hopefully a justifiable alternative!

Thanks for the advice I'll give it a wirl tomorrow when I get some time to code

Isn't this how the Terminator apocalypse starts?