Autonomous Satellite Tracker

This page refers to my article in March/April 2016 QEX. Any updates will be posted here.

Supporting Material:



  • Version 2016061704 fixes a problem that prevented entering values in Firefox and Android.
  • Version 2016073023 fixes a problem that prevented downloading elements from AMSAT or
    Celestrak in Firefox and Android.
  • Version 2016082822 fixes a problem with refraction near the horizon.
  • I've added a closeup photo of the way I connected the tracker to a tripod. I bought a
    small tripod and pulled the center post up through a channel then clamped to it. The
    tripod post is 5/8" diameter. ServoCity part numbers: 3x 585548, 1x 585443, 1x 545360
    and 2x 585596.
  • Notes from a builder, WA7DLG.

Update July 15 2018: I have nearly completed porting to the ESP8266 processor, the same one used in my HamClock. This will eliminate the need for the ethernet shield and the TP-Link. For the most part it all works very well except communication with the BNO055 orientation sensor is not reliable. The issue seems to be the sensor uses I2C clock stretching which is not supported by the ESP I2C subsystem. Until and unless I find a way to resolve this please stick with the system as originally designed.

73, Elwood Downey, WBØOEW