December 29, 2012
Robotic Plotter Arm
We do embedded C on STM32. The only hardware interfacing was the 3 PWM outputs controlling each motor. I did struggle for some time in producing a signal with the correct frequency and pulse width, and to varies the pulse width smoothly at a desired speed.
Luckily the control algorithm is not hard.
In order to design the desired Hugo's drawing, I scratched up a simple vector graphics editor. The editor can export a vector design into a format accepted by the embedded program.
Finally it gave me this drawing.
Compare with the drawing by Hugo's automaton.
It took smaller amount of time and effort than I had expected to finish this arm. That's 10 days of spare time and 3 days of full time.
There is indeed much room for improvement of accuracy. But then I am satisfied by how pieces of hardware and software work together to create the artistic outcome.
Appendix I - photo album
sample sketches produced by the arm
Appendix II - presentation slides
Appendix III - demonstration video
Appendix VI - source code