Conference Papers

EasyTrak, A PIC Based Rotor/Radio Controller Interface

 by Steven R. Bible, N7HPR


EasyTrak is a rotor/radio controller interface based on the Microchip PIC16F87x series PICmicro microcontroller.  The goal was to design a rotor/radio interface that is compact, low-cost and easy to use.  The PIC microcontroller contains many of the peripherals needed to design a rotor/radio controller interface: analog to digital converter (ADC), timers, serial interface (USART), and individually programmable I/O pins.  In addition, the PIC contains FLASH ROM for easy programming and upgrades, RAM for system variables, and EEPROM for storage of non-volatile configuration information.  With a small amount of interface circuitry around the PIC microcontroller, the goals of compact and low-cost were obtained.  Ease of use was obtained by designing EasyTrak to interface to the most popular azimuth/elevation rotors and a serial RS-232 interface to communicate with virtually any computer.

EasyTrak is designed to easily interface to the Yaesu series of azimuth/elevation rotors, model numbers G5400B, G5600, and the newest G5500.  These rotors have a computer interface built in with an 8-pin DIN connector on the back of the rotor controller to control left, right, down, up and provide rotor position via a proportional 0-5 VDC analog signal for azimuth and elevation.  EasyTrak can be interface to other rotors, for example rotating HF antennas, but will require user modification of the rotor controller.  Optional relays can be installed on EasyTrak to provide normally-open (NO) or normally-closed (NC) contacts for azimuth, elevation, and brake.

The computer interface is via a serial RS-232 connection.  The rotor controller protocol is based on Chris Jacksonís, G7UPN, EasyComm protocol.  EasyComm is a simple ASCII character based protocol for controlling rotors and radios.  The benefit was that a new protocol did not have to be created, it is easy for programmers to write for and interface to, and several programs already have EasyComm programmed in: WiSP, Nova, MacDoppler, MacAPRS and WinAPRS.  The Mac and WinAPRS programs have the unique feature of tracking high and low altitude balloons in azimuth and elevation as well as other objects.  Mac and WinAPRS can also point HF beams using the DX Cluster feature or point to a moving object in azimuth only.

KE6JAB EasyTrak Radio Controller

The EasyTrak Radio Tuner was custom designed for Ronald Ross, KE6JAB, for a two month expedition to Antarctica starting in November 2000. For more information click here.

Page last revised: August 27, 2000 - N7HPR