PIC Servo Controller

Note: this is a project from 2001. It is only mentioned here for completeness. A commercial version was produced that successfully controlled a fully articulated biped.

This little board (1½ x 1½ inches sq, 4 x 4 cm²) controlls up to 14 R/C servos, enough to make a six legged robot walk and its head move. It connects to the PC via an RS 232 serial line or to Basic Stamp and other microcontrollers via a TTL level serial connection.


  • stackable - up to 15 modules can be connected
  • robust - controller is protected from spikes
  • small - 1x1 inch sq plus connectors
  • easy - power and serial connecter fit one-way only
  • fast - position change for all servos up to 100 times per second

Top View

The controller needs a lot of pins to communicate with the world. The top row in the picture on the right shows 6 servo connectors (three blocks of two each). On the top left is the RS232 connector, below is the power connector. The bottom shows another six servo connectors. The connectors on the right are used to stack controllers and an optional RS232 voltage converter.

*prototype board shown. Production board will differ.

Bottom View

The test setup was fabricated using many short wires that connect all pins below the board. Now that the layout is tested a final layout can be created and etched.

Test Setup

The board tested fine. I connected servos to all ports and they all manipulate the servos simultaneously. Power drag from the servos can be very high! Be sure to use matching batteries.

Serial Level Conversion

Standard PC serial ports use voltages of +/-14 Volt to signal a digital 0 or 1. The RS232 adapter board plugs neatly into the Servo Control and provides voltage conversion in from and to the serial line.

Coming Soon

  • RS422 interface
  • I2C bus interface
  • USB interface
  • sensor module
  • motor module
  • stepper module
  • Servo Control Test Application:

If you visit us often you know that these pages change fast. The Servo Controller chip will be for sale shortly, including tester, sample source code and a full featured Robot Animation Software. I know that you will love it! Estimated price for the controller chip is $8.90. The module will be about $18.90 for the complete kit and $25.90 for the assembled version.