If you've got an Arduino of any variety, you might have noticed some of the pins on the board have a tilde mark or PWM printed next to them. What is PWM?

Multicopters generally use Proportional-Integral-Derivative (PID) control loops to maintain stability in the air. [AA] used the Arduino PID library for his quadcopter.

Most projects are built on abstractions. After all, few of us can create our own wire, our own transistors, or our own integrated circuits. A few months ago, [Julian Ilett] found a problem using th… ...