The Servo Buddy
This article introduces servo motor construction and operation, and describes an inexpensive circuit you can build to control a servo without a microcontroller. When I first started to build projects with R/C servo motors it became clear that, during construction, I needed a way to set the position of a servo manually. You can’t just grab the shaft and turn it, and writing software for a micro was overkill. Just a simple little circuit would do the job. That was the birth of the Servo Buddy....