Let's Make Robots!


Just walking

As I discovered "Bob" I had purple filament in my office 3D printer. Well, i thought it would not make it to the robot section since I am not having enough time to finish it. 

Seeing the Blue Bob and the Yellow Bob drove me to publish it.

As you can see, my Bob is quite not done. I still not put a sensor in it since I just wanted to see it walking LOL

Never mind, I guess Bob is sexy also without the sensor, also if his face is missing something without it.

The print was ok with the first try. I printed with 50% filling but wished to do the both servo brackets with 100%

Quick assembling with the servo screws. See the right bracket was already broken and fixed with 2 component rubber glue.

Funny that the switch is also on the position as I saw in the other Bob

Bob's brain is a DFRobot Arduino Mini Pro...

...with a DIY servo shield...and charging plug (yes, beat me but I did not have another (smaller) one :-) )

Driven by a LiPo but still not very stable in walking. The center of gravity is still to high in my Bob.

I will not mark it as finished because I am still confident to add a sensor on it and give it a modified programming.

But for now I will stop here and point you to the original and the blue and yellow Bob page (see links above) to learn more. Video will come later tonight. Video is online but I never get the aspect ratio right in that Youku player...Youtube is still processing since last night...76MB video...seems there is something jammed...

EDIT: Will try Protowrxs code to make him more stable: http://letsmakerobots.com/node/35877

UPDATE: Youtube video is online and it's at 50% slow motion :-)

UPDATE: I finished BoB during the campus party in London. I've uploaded the code of FrankenBob. Sadly, he broke his legs on the way back to China, so I printed him two new legs, only that the color is not matching with his teint. Anyway, now he'll be packed and shown at the Maker CarnivalShanghai. Marked as finished, Purple BoB is done!!!

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Dude, you are truly prolific. Nicely done!

As others have said, I love the colour.  Now just need to alter the software a little, so the foot servo does not let him tip quite so far.


the code helps a lot to.mine is very rough..but when using protos code he walks even with the battery on his head


Is it just me or do the various "Bob" walking video's all seem to lean farther to the robots right when walking. Thus making them tend to fall to the right. I have no interest in building a Bob (I'm still working on my own walking biped robot), but if I'm correct I would fix this leaning fall to the right problem before changing code. I'm completely speculating here but it seems like it would be from a physical difference between the left leg and right leg ???

It's just my horrible proof of concept code. Bob is perfectly symmetrical

Why dont you redesign the feet to be battery holders? This would improve the center or gravity an leave more room in the head for other sensors and toys.

what do you think of a single aa lithium cell in each foot? got any measurements for a holder? ill make the feet ,someone else will have to try them

I would be down to print out some new feet to make Bob walk a little better. My intern has been playing around with him trying to make him walk better, but has not been able to accomplish much.

Slightly different in terms of size. AA = 14500, 18650 = 18650 (so 4mm thicker, and 15mm longer). I looked at a couple ebay listings for the single-cell 18650 holders and they all dim them out at (7.2 x 2 x 1.9)cm/ (2.83 x 0.78 x 0.74)inch (L x W x H).

edit - link added with example of what I was looking at.


i am with the rest of the world in using the metric system so all bobs are metric. now to design a new foot...would you guys like the cells hidden or just wider feet with space for the holders on top?