Arduino Nano PI Main Discussion

[dingbatca]

I did see post #495. Do you still think that will make a difference knowing pins 1, 2, and 3 are just shorted in the coil side plug?

[bklein]

Also, what are the marked PIN numbers of the front two pins seen in your photo. The left one seems to have a marking like a “5” which wouldn’t be right.

Never mind - I can see how it would be correct.

[Qiaozhi]

More info. Two shielded cables to the connector boot. Only one is wired into the connector. Jumpers across pins 1-5 and 2-3-4. I don't think this info helps. :-(

Any other ideas?

Did you see post #495?
This information would help in determining the problem.

[dingbatca]

More info. Two shielded cables to the connector boot. Only one is wired into the connector. Jumpers across pins 1-5 and 2-3-4. I don't think this info helps. :-(

Any other ideas?

[Qiaozhi]

I just finished this detector. It performs good when tested indoor. I don’t know why main sample width is little bigger (1-2us) than efe sample. It might be noisy in real conditions?

Main: [ATTACH]56516[/ATTACH]
Efe: [ATTACH]56515[/ATTACH]
Main pulse vs opamp out: [ATTACH]56517[/ATTACH]
Board: [ATTACH]56518[/ATTACH]

They should be the same, but the discrepancy should not make a noticeable difference in use. If you want to tweak the settings, then change efeSampleOffset in the sketch. It's currently set to 4us.

[ionut_mtb]

I just finished this detector. It performs good when tested indoor. I don’t know why main sample width is little bigger (1-2us) than efe sample. It might be noisy in real conditions?

Main:
Efe:
Main pulse vs opamp out:
Board:

[bklein]

Also, what are the marked PIN numbers of the front two pins seen in your photo. The left one seems to have a marking like a “5” which wouldn’t be right.

[Qiaozhi]

Very strange...

Two questions:

1. Can you probe the coil plug with a multimeter and find which pins the mono loop is connected to? I would presume it will be pins 4 and 5.
2. If this is the case, then try connecting the ANPI to only those pins. i.e. leave pins 1, 2, and 3 disconnected. What is the result?

[dingbatca]

More info.

Videos:
GPX Air Sweeps
GPX Sweeps
Simple coil

More pics attached.

[green]

I believe I am following the coil pin out correctly. Thanks for posting that @bklein.

No false signal when my hand is near, on, or sweeping over the coil(s).

Photos attached. My home brew socket adapter has a 350ohm damping resistor. I think the perfect value for the GPX is 340~350ohms, based on what I am seeing from my oscope.

In the field I have been using a simple elliptical coil. It works rather well. I need to try my basket out to see if it's getting the same failure mode as the GPX. I will strive to pull that off tomorrow. A bit tricky with a newborn in the house.

Thanks for the photos. The GPX coil no target trace appears to take twice the time to flatten as the basket no target coil trace. What could cause the slower decay?

[Qiaozhi]

I believe I am following the coil pin out correctly. Thanks for posting that @bklein.

No false signal when my hand is near, on, or sweeping over the coil(s).

Photos attached. My home brew socket adapter has a 350ohm damping resistor. I think the perfect value for the GPX is 340~350ohms, based on what I am seeing from my oscope.

In the field I have been using a simple elliptical coil. It works rather well. I need to try my basket out to see if it's getting the same failure mode as the GPX. I will strive to pull that off tomorrow. A bit tricky with a newborn in the house.

Thanks for posting the socket adapter photo, but I cannot see how it's wired up, even if I zoom in. A simple hand-drawn diagram may be better.

[surfdetector]

I believe I am following the coil pin out correctly. Thanks for posting that @bklein.

No false signal when my hand is near, on, or sweeping over the coil(s).

Photos attached. My home brew socket adapter has a 350ohm damping resistor. I think the perfect value for the GPX is 340~350ohms, based on what I am seeing from my oscope.

In the field I have been using a simple elliptical coil. It works rather well. I need to try my basket out to see if it's getting the same failure mode as the GPX. I will strive to pull that off tomorrow. A bit tricky with a newborn in the house.

The socket adapter picture appears to show a cold solder joint at the top of your resistor connection.

[green]

Would the GPX coil work if the delay times were the same for both coils?

[dingbatca]

I believe I am following the coil pin out correctly. Thanks for posting that @bklein.

No false signal when my hand is near, on, or sweeping over the coil(s).

Photos attached. My home brew socket adapter has a 350ohm damping resistor. I think the perfect value for the GPX is 340~350ohms, based on what I am seeing from my oscope.

In the field I have been using a simple elliptical coil. It works rather well. I need to try my basket out to see if it's getting the same failure mode as the GPX. I will strive to pull that off tomorrow. A bit tricky with a newborn in the house.

[bklein]

The Detech site says this (I wonder if it is causing trouble? What do they have in the coil for this?):
Detech is the first to build coils with magnetic sensors, enabling pulse induction detectors to discriminate between ferrous and non-ferrous metals.