Let's Make Robots!

Biped walker with 3 servos - Arduino version

DeadDuckWalking-Arduino.pde1.84 KB

This is based on fritsl's "Biped walker with 3 servos (Dead Duck Walking)", http://letsmakerobots.com/node/29379.

I am familiar with Arduino/AVR rather than PICAxe, so I adapted the code to that. I set out to use an AtTiny 8 pin DIP, but it was easier to use the Servo library as-is with an AtMega328p. I may go back to the AtTiny when/if I move the circuit off the breadboard.  Note that I didn't actually use a full Arduino board, but I did use their IDE and Servo library, and sent the resulting code to a stand-alone microprocessor.

I followed fritsl's build video (a no-talker which I really enjoyed) very closely. I cut my own wood pieces rather than starting with paint sticks, but that makes no real difference. I took my time and tried to be careful with cutting and glueing the parts, but I positioned the foot servos too low on the vertical balance pieces (not sure what to call them) and as a result I had to insert a shim between the foot servo arms and the wood feet to avoid binding.

Since it is built of wood and not metal/plastic or some other "hard" material it can feel a bit loose and clunky, but that is part of the charm I think. Working with the wood is pretty forgiving.

I had never used a hot-melt glue gun before. I used my wife's cheap crafty low temp glue gun, and it worked fine. I liked it and expect I will be using it more.  None of the glue joints have come apart yet.

A critical part of the build and code is servo alignment.  I note in the code the proper rotation of the servo arms at center setting (1500 usecs).  That should be set properly at glue-up time.  It can be tweaked a bit in the code after the gluing but it is best to get it right at first.


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hi please could you watch this video, i am making this robot and i have come across this, is this a problem or does it really matter, when the right servo is in the air, the middle one is flat against both of the servos, but when the left servo is in the air, the middle servo is diagonallly touching both the right and left servos, watch the video to understand, either comment on the video or back on here, here is the link for the video: http://www.youtube.com/watch?v=MZg50gkjmBM

Any progress with the ATTiny attempt?

very cool!

That's a very nice job, edllew :)
I love bipeds!

It's always amazing what you guys up to. I really should try the Dead Duck Walking to...i mean with a robot...not myself ;-)

Well, now i want to see it walking with the ATTiny ;-)

I just ordered two dozend and need to build them in somewhere ;-)