8 Channel R/C Servo Controller for the uBot-3
This project was created in the Fall of 2004 to control 6 hobby servos for two 3 DOF arms in the uBot-3.
Servo Testing
The servo project breadboarded and connected to a laptop.
Oscilloscope Pictures
Servos take a pulse between 1 and 2 ms in length as an input for a commanded position. Here are some pictures at 1 ms/div horizontal and 1 V/div vertically of the output of one channel on an oscilloscope. Pictures show a 0.6 ms pulse, 1.5 ms pulse, and 2.4 ms pulse.
Pulses are sent at 50 times per second (10 ms/div here) when enabled.
VB Demo Software
Here's software written to demostrate the servo project was working. It also has position and torque feedback not shown in this early screenshot.
Final PCB
The working project was put onto a small printed circuit board. It only requires a 12 V battery and serial port connection to control up to eight hobby servos. It has feedback for position and current.
