“This application note describes a circuit designed to control the speed of a dc motor used in radio-controlled boats. The electronic speed controller (ESC) is a “no-brake, forward-only” controller. I wanted to keep the part count low and the circuit simple so a couple features were sacrificed. The circuit does not have: over-current protection, over-temp protection, polarity protection, or over/under voltage protection. All the parts can be obtained from digikey distributors. The circuit was designed with a popular 12-cell model boat motor in mind (graupner speed 700). This project was my first attempt at using Bascom-avr and Atmel microcontrollers. ” Thanks JasonR! Link.