Geotagging metal detector

Have built a heavy 55kg 4wd skid steer rover and intend to sweep a field while dragging a metal detector. Most hobby commercial detectors don’t have any data output so I will probably use the audio jack and convert to an ‘event level’ signal.
I thought to link this up to a paint spray can so you can later check areas of interest .

Is there a way to signal the cube and store GPS location with the detector output level please?

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Sounds interesting, would like to see the rover out of interest, so you’d be looking to drive an event off the change of tone from the audio output where if a threshold frequency was exceeded a gps marker would be placed or a spray can would put paint.
Isn’t detecting based on being able to replicate the tone shift or attenuation many times over the same physical location to confirm the sound wasn’t just an anomaly?
Either way it sounds like the audio signal would probably need to go into a raspi or similar for processing with the result driving a gpio pin which could interface with the flight controller to mark the point.

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You are correct, that’s basically what I want to do. I would not expect to put a spade in the ground based on a marker just from this but it would direct you to areas to use a hand held device and may show up ‘feature rich’ areas.
As this thing is welded steel I will probably pull a non metallic trailer but will have to make this skid steer vehicle do large radius turns,

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Sure, I think this is the way to go on this project, use some kind of raspberry or arduino to convert this audio output into GPIO. Then I think you could setup your rover params to recognize this signal as a camera trigger for instance, so when you download your log you can retrieve the GPS coordinates that your metal detector found something.

Looks like a very interesting project man! Good luck on it and share your results here with us if possible!

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I think in its simplest form an Arduino could be used to generate an ‘on/off’ signal triggered by audio output however if possible it would be good to get more detail form the detector…
Most good detectors (eg Deus 2), can distinguish between metal types and the unit can be setup to generate different audio tone based on the metal type. Its probably not too difficult to get an arduino to raise different pins depending on frequency. The difficulty (for me anyway) would be to record and store that info in the Cube with GPS tag. Thats why I initially favored a spray can on a relay.

There are lots of ways to skin this cat, some of which could get rather complex if you so choose.

The simplest way I can think of to “geotag” locations based on GPIO input is to enable button input and connect your microcontroller output pin to the autopilot as a button. Assign “SaveWP” to that pin’s BTN_FUNCx parameter.

When you create your nav mission, set the last planned point as an unlimited loiter. Any point stored after that will be geotagged information, and the Rover will still stop at the end of the planned section of the mission.


However, I think onboard scripting will be your only choice if you want to store more granular information based on multiple pins, as you describe in your last post.


Nice ideas @Yuri_Rage, thanks for sharing!

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Won’t doing a SaveWP during an auto mission trigger an RTL?

It won’t. I just tested while my mower was running. However, it appears it may not actually do anything at all while the mission is running, so I think you’ll need to do some scripting magic, anyway.