<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div>One thing that jumps to my mind is ins of some sort fused with gps location by Kalman filter to produce a stable position estimate. Maybe? (Probably still not quite precise enough for a thing with a spinny blade ;) )</div><div id="AppleMailSignature">-Alex <br><br>Sent from my iPhone</div><div><br>On Jul 27, 2016, at 9:32 PM, Ken Boone <a href="mailto:kensrobots@gmail.com">kensrobots@gmail.com</a> [trianglerobotics] <<a href="mailto:trianglerobotics@yahoogroups.com">trianglerobotics@yahoogroups.com</a>> wrote:<br><br></div><blockquote type="cite"><div>
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<p></p><p dir="ltr">I already have a lawn mowing robot test bed I built back in the 80s. The optical beacon navigation i designed proved to be too inaccurate. The mower is described on <a href="http://kensrobots.com">kensrobots.com</a>.</p>
<p dir="ltr">After a while when bench testing or displaying my fixed wing UAV the ground station displays a wobbly path taken around its fixed location. </p>
<p dir="ltr">A question? For mowing navigation could a fixed GPS receiver at my house be used to increase mower location accuracy with an identical receiver on the mower.</p>
<p dir="ltr">First average fixed location readings to establish the fixed receiver location. Then use differences to correct mower location? </p>
<p dir="ltr">I've been experimenting with the mower because I have grass and it is a neat challenge. Too much liability envolved in mowing to want to develop a product. <br>
Ken</p>
<p dir="ltr">On Jul 27, 2016 5:17 PM, "Tadd Torborg" <<a href="mailto:tadd@mac.com">tadd@mac.com</a>> wrote:<br>
><br>
> Firmware has to be pretty stable and well done since the transponder end has to turn around and answer. Counter/timers needs to be very good/fast/well-understood. <br>
><br>
> There are other off-the shelf solutions already. Look for Decawave TREK1000. I don't think Decawave is open source. <br>
><br>
> Range will be like cheap Wifi stations talking to each other, i.e. no nice antennas. Good enough for lawn mower if you have two anchors line of site visible to the lawn mower at all times. Put the intelligence on the lawn mower or in the house, and make solar powered anchors, look like driveway-light pedestals. <br>
><br>
> Tricky project. I'm less scared of the range finding than I am of the robotics part of running a lawn mower around, so maybe it's not so hard. Anybody want to get together on the lawn mower? <br>
><br>
> Tadd<br>
><br>
> On Jul 27, 2016, at 09:32 AM, Ken Boone via TriEmbed <<a href="mailto:triembed@triembed.org">triembed@triembed.org</a>> wrote:<br>
><br>
>> Kickstart info below this comment.<br>
>><br>
>> I started out experimenting/learning with a Knight-Kit 10 in 1 vacuum tube kit.<br>
>><br>
>> It's amazing what technologies and resources are now available for students, hobbyists and garage/basement experimenters/inventors.<br>
>><br>
>> More on the ranging modules.<br>
>><br>
>> The modules uses fixed location nodes for xyz ranging of moving nodes or for your swarm distances between moving nodes.<br>
>><br>
>> Wonder what's the maximum range? <br>
>><br>
>> Might need to resurrect my robotic lawnmower which needed a better ranging system.<br>
>><br>
>> From site: <a href="https://www.kickstarter.com/projects/subpos/subpos-ranger-indoor-positioning-system/description">https://www.kickstarter.com/projects/subpos/subpos-ranger-indoor-positioning-system/description</a><br>
>><br>
>> "The Ranger Boards accurately determine the distance between one and other through phase shift/difference measurement and accurate timing techniques in the onboard Atmel AT86RF233 chipset. This is similar to how laser range finders work, except instead of light it uses 2.4GHz radio frequencies. The multiple antennas on board allow for multiple out of phase measurements to mitigate multipath effects, to best determine the distance between the Ranger Boards."<br>
>><br>
>> Create - dream, imagine, experiment - Create. .............<br>
>><br>
>> Ken Boone <br>
>><br>
>> _______________________________________________<br>
>> Triangle, NC Embedded Computing mailing list<br>
>> <a href="mailto:TriEmbed@triembed.org">TriEmbed@triembed.org</a><br>
>> <a href="http://mail.triembed.org/mailman/listinfo/triembed_triembed.org">http://mail.triembed.org/mailman/listinfo/triembed_triembed.org</a><br>
>> TriEmbed web site: <a href="http://TriEmbed.org">http://TriEmbed.org</a><br></p>
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