OpenServo Hardware

The OpenServo hardware is documented in the links below.


OpenServo 3.0 Information

Main page: OpenServoV3. Summary:

OpenServo 3.0 is the latest version of the OpenServo hardware based on the AVR ATmega168 MCUs. This MCU has 16K of Flash allowing more features to be implemented. This version of the OpenServo also uses independent bridge control and back EMF sensing.

Download the whole Cliff Huston OpenServo V3 package here:

Includes PCB, schematics, BOM and documentation.


Open Encoder (OpenEncoder) is a digital I2C full rotation position feed back device, designed to replace the position-sensing pot that came with the servo.

SparkFun OpenServo ROB-09014

What is this SparkFun OpenServo ROB-09014?

OpenServo 2.1 Information

Main page: OpenServoV2. Summary:

This is the stable version of the OpenServo hardware based on the AVR ATmega8 and AVR ATmega168 MCUs. These MCUs have 8K and 16K of Flash respectively allowing more features to be implemented. This version of the OpenServo also uses International Rectifier IRF7309 MOSFET (or equivalent) for greater current capacity.

OpenServo 1.1 Information

OpenServo 1.1 is based on the AVR ATtiny45 MCU with 4K of Flash. Unfortunately, the AVR ATtiny85 MCU with 8K of Flash has not yet been released by Atmel. Because of the limited Flash memory the ATtiny45 version of the OpenServo is considered to be obsolete. This design may be resurrected if and when Atmel finally releases the ATtiny85.

edit: The ATtiny85 has been officially released, and is available through Digikey. Updates to v1.1 are being made at this time and will be hosted here shortly.

earlier servo replacement PCBs

A few other people have developed PCBs vaguely similar in one way or another to OpenServo PCBs.

Colin MacKenzie provided the original inspiration for the development of the OpenServo. Colin developed a similar servo board called the SuperServo for his Symapod robot using the PIC16C73A and was kind enough to share his design. Aspects of Colin's hardware design were borrowed for the OpenServo.

Six transistor H-Bridge PCB replacement for servo PCB is a much simpler internal servo PCB replacement board.

The Netmedia 8T servo controller provides live torque/load information for each attached servo.

On the "Molecubes For Everyone" wiki, the "Assembly of an Actuator Molecube" briefly shows a servo controller PCB that looks suspiciously similar to an OpenServo.

The Robot Room: Monkey Mints Robot by David Cook uses a Atmel ATtiny85 AVR. We probably would have used the same MCU for OpenServoV2 and OpenServoV3 but it was not yet available then. See the "ATtiny45 vs. ATtiny85" thread for details.

Servo Hardware Information

see also

Return to OpenServo Front Page

Hardware (last edited 2012-10-12 19:51:18 by localhost)