I built and sold around 200 of these custom controller boards. These boards provide a plug-and-play solution for paintball players who want to build their own paintball sentry gun.
I sold around 200 of these boards, originally soldering them by hand, and later using American Circuits for manufacturing and assembly. The board itself communicated with a computer over a USB connection. It takes a power supply input, and drives three servo motors - one for pan, one for tilt, and one to squeeze the trigger of the paintball gun. In addition, the board provides a wiring interface for guns with an electronic trigger. The design is based on an ATmega328 microcontroller and and FT232RL USB to serial converter. I went through eight iterations of the design over about two years.
Before I contracted assembly out to a manufacturer, I assembled about 90 of these boards by hand, using solder paste stenciling, tweezers, and a hot plate. The boards were sold as part of a kit (along with servos and cables), or optionally, by themselves.
This controller is made to work with Project Sentry Gun, one of my longer-running projects. My open-source code and custom controller hardware is used for training by the St. Louis Police Dept and the Royal Australian Navy, among others.
Instructional and demo videos. 1.1 million views.
The Project Sentry Gun website has instructions, code, and a large user forum.