Let's Make Robots!

Monoservo robot - second problem

One motor stepper

Hi guys,
this is my next robot of the series "simple robots", it should be easy :) .

After having my robot "Big M" built, I showed him my friend. He said: This is not difficult to build a robot with three motors. He would use only two motors.
This was challenge:)
I decided: I build a robot with only one motor. But how???????????????
Helped me my "Big M stepper".

First I'll show you only the lateral movement


















And here are a few photos:

He is built from wood and plywood.




 Here you can see one magnet, he pulling the stick.


and here is a rad which the robot moves to the side








Version 2 (2010.0.29)

I built second version, but it was not perfect, he did not just work:(




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does that wheel with the spikes have some sort of preload spring, or one-way bearing?
In my opinion, the one-way wheel slips on the table. Try to attach to it, a bigger, normal wheel to make contact with the table.
I built second version with a bigger wheel, but it was not perfect,  he did not just work :(

Cool concept. Can  you describe your problem in more detail. It is a bit difficult to provide suggestions since we don't know what you are trying to do.

What is the robot suppposed to be doing? Moving just forward? What is the ratchet gear in the back supposed to do? It looks like it is designed to move in only one direction, but it seems to be spinning both ways. If a one way ratchet action is what you want, you might need the little leaf spring between the nails to be more stiff. It looks like it is flexing enough to allow the ratchet to move counter-clockwise.


the driving style is very simple.
1) robot lifts his arm forward,
2) it falls over and pulls the rest. (the wheel does not move)
3) if he sees a wall, he makes such a motion as in the film and turns around
4) he turns, he turns, he turns, he turns, he turns ,.....
5) and back to point 1

So it should work, but he turns the wheel without moving :)