Introduction

The Johns, Rodgers, and Wojno Radio Frequency communication device: is a way to easily enable half-duplex communication between HandyBoards separated by under and slightly over 35 meters. It was designed in 2005 to accommodate short and limited transmissions over the FM band to enable robotic communication and collaboration in CSCI445: USC’s undergraduate robotics course.

Hardware Documentation

A far better explanation is can be found in the documentation (and somewhat of a journal) of the construction of the device. It also includes details on how to build your own.

Drivers

Also developed, were a set of software drivers to operate the device within the IC5 and IC6 programming “languages.” With these drivers, you can easily perform the essential operations of the devices. All of those operations are described in the code documentation. Also attempted was a TCP/IP layer, however, the complexity precluded completion, testing, and subsequent implementation.

Heads up and Tips

A word of warning: if you are using multiples of these devices, you will encounter interference. The devices can be addressed (8 unique pairings, 16 unique addresses), however they still operate on the same frequency. The TCP library was designed to help correct this.

A word of adventure: Not tested, but desired, was a token ring-like architecture (seems strange over wireless) to that collisions are completely eliminated and broadcasts are now possible. However, you will need network reconfiguration automation should the robots go out of range of each other, and there is a considerable amount of overhead associated with the token and storing messages.