Adaptive Bicore Biomech Motor Controller (Abcore)
From BEAM Robotics Wiki
Mark Tilden introduced the Abcore in the Junkbots, Bugbots, and Bots on Wheels book. Given a DC motor with a winding resistance > 10 Ohms, the Abcore is a self-oscillating H-Bridge motor driver.
Circuit Variations - Headbots. "Replace the 4.7K internal biasing resistors with CdS photoresistors for phototropic oscillations (ideal for headbots). No further electronics required." (Page 336). - Biasing and balancing. Place a 100K Multi-turn Trimpot between the bias points and Vcc. Use the trimpot to bias the Abcore or balance the oscillations. - Timing. The default oscillation period is around 4 seconds. Place a resistor across the inputs to adjust this time period. - Master/Slave. Run a 1K or higher resistor from the output of one Abcore to the input of the next to create a M/S pair.