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{
    "url": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/F2FUWS5D2CD4GJCRKXA7JJZMYIKKDNJX/",
    "mailinglist": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/",
    "message_id": "[email protected]",
    "message_id_hash": "F2FUWS5D2CD4GJCRKXA7JJZMYIKKDNJX",
    "thread": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/thread/QK4JAWBEVOFZ7CL7QJOE5UMAP2JETLYA/",
    "sender": {
        "address": "zleffke (a) vt.edu",
        "mailman_id": "57a24afb1cf641f98121841e6753c12e",
        "emails": "https://mailman.amsat.org/hyperkitty/api/sender/57a24afb1cf641f98121841e6753c12e/emails/"
    },
    "sender_name": "Zach Leffke",
    "subject": "Re: [amsat-bb] Remote sensor for antenna array orientation",
    "date": "2016-02-18T20:50:50Z",
    "parent": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/QK4JAWBEVOFZ7CL7QJOE5UMAP2JETLYA/",
    "children": [],
    "votes": {
        "likes": 0,
        "dislikes": 0,
        "status": "neutral"
    },
    "content": "Hi Clayton,\n     I used an accelerometer for elevation feedback and a magnetometer \nfor azimuth feedback as part of a system that drove arrow style antennas \non a PTZ camera mount that did not have any feedback sensors built in.  \nAll purchased at sparkfun (or adafruit can't remember) and driven by an \narduino atmega328p using (basically the arduino Uno, there was also \nreference arduino code for getting the things up and running on the \nwebsite I bought them from).\n\nI wrote up and published the circuit design for that system in the \nproceedings of the 2013 symposium.  If you need a copy of the paper I \ncan probably dig it up from wherever I saved it.\n\nMy experience with it was that the accelerometer was rock solid for tilt \nor elevation feedback.\n\nThe magnetometer on the other hand was shall we say 'finicky.'  It did \nwork for my purposes, but required re-calibration frequently, and \nre-calibration basically every time you moved the set up to a new \nlocation.  It also had pretty noisy measurement data where the angle \nreported by the device would 'bounce around' even when the sensor was \nstationary.  So I had to play games with the arduino to keep a running \naverage of the feedback to smooth out the noisy feedback.  Also, the \naccuracy of the magnetometer data was decent but not great.  If you have \nsomething like an arrow antenna with a fairly broad beam, then it was \ngood enough, but if you need \"precision pointing\" then the magnetometer \nis probably not the way to go.\n\nAll of my experiences were based on a pretty cheap device from spark \nfun.  It could be that cell phone technology has caught up and something \nthat you can get on those websites for cheap is more robust than the \nsensor I used.\n\nHope this helps,\n\n-Zach, KJ4QLP\n\nResearch Associate\nTed & Karyn Hume Center for National Security & Technology\nVirginia Polytechnic Institute & State University\nWork Phone: 540-231-4174\nCell Phone: 540-808-6305\n\nOn 2/18/2016 1:58 PM, Clayton W5PFG wrote:\n> Has anyone ever mounted a mutli-axis accelerometer or a magnetic \n> compass sensor to their antenna crossboom for making adjustments to \n> point of aim?\n>\n> I'm currently using Hall Effect sensors but experiencing several \n> degrees of drift over a short period of a few days.\n>\n> 73\n> Clayton\n> W5PFG\n>\n>\n> _______________________________________________\n> Sent via [email protected]. AMSAT-NA makes this open forum available\n> to all interested persons worldwide without requiring membership. \n> Opinions expressed\n> are solely those of the author, and do not reflect the official views \n> of AMSAT-NA.\n> Not an AMSAT-NA member? Join now to support the amateur satellite \n> program!\n> Subscription settings: http://www.amsat.org/mailman/listinfo/amsat-bb\n\n",
    "attachments": []
}