Hi Clayton, I used an accelerometer for elevation feedback and a magnetometer for azimuth feedback as part of a system that drove arrow style antennas on a PTZ camera mount that did not have any feedback sensors built in. All purchased at sparkfun (or adafruit can't remember) and driven by an arduino atmega328p using (basically the arduino Uno, there was also reference arduino code for getting the things up and running on the website I bought them from).
I wrote up and published the circuit design for that system in the proceedings of the 2013 symposium. If you need a copy of the paper I can probably dig it up from wherever I saved it.
My experience with it was that the accelerometer was rock solid for tilt or elevation feedback.
The magnetometer on the other hand was shall we say 'finicky.' It did work for my purposes, but required re-calibration frequently, and re-calibration basically every time you moved the set up to a new location. It also had pretty noisy measurement data where the angle reported by the device would 'bounce around' even when the sensor was stationary. So I had to play games with the arduino to keep a running average of the feedback to smooth out the noisy feedback. Also, the accuracy of the magnetometer data was decent but not great. If you have something like an arrow antenna with a fairly broad beam, then it was good enough, but if you need "precision pointing" then the magnetometer is probably not the way to go.
All of my experiences were based on a pretty cheap device from spark fun. It could be that cell phone technology has caught up and something that you can get on those websites for cheap is more robust than the sensor I used.
Hope this helps,
-Zach, KJ4QLP
Research Associate Ted & Karyn Hume Center for National Security & Technology Virginia Polytechnic Institute & State University Work Phone: 540-231-4174 Cell Phone: 540-808-6305
On 2/18/2016 1:58 PM, Clayton W5PFG wrote:
Has anyone ever mounted a mutli-axis accelerometer or a magnetic compass sensor to their antenna crossboom for making adjustments to point of aim?
I'm currently using Hall Effect sensors but experiencing several degrees of drift over a short period of a few days.
73 Clayton W5PFG
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