While working on one of my DIY projects, I’ve ordered some really nice retracts with linear actuators from HobbyKing, available here. As soon as I got that cool stuff from them, I realized that the controller (picture on the right) did not work like I would like it to. Although it would fit most RC projects, my demands from it were a tad different. In the original scenario, the controller is hooked onto one of your receivers channels, and would drive the retracts connected to it according to the PWM signal it receives – which are in most cases translated from a stick position on your remote, or a state of a button. In my case, I wanted the controller to retract or extend upon receiving a signal from a GPIO, and pinging back, to another GPIO, whenever the requested action is finished. I had several options to approach this problem: Buy another controller Find a way to download the program from this controller, reverse engineer it, and change to my needs “Reverse engineer” the circuitry, and build a new program for it, accommodating my needs