Arduino Nano PI Main Discussion

[Qiaozhi]

What depths on the coils?

Results with 9" (230mm) diameter coil.
See attached file.

[waltr]

Results with 9" (230mm) diameter coil.
See attached file.

Those are good distances. Guessing this is 'air' tests.

[Qiaozhi]

Those are good distances. Guessing this is 'air' tests.

Correct, those are air test results. However, unlike a VLF, PI detectors show little or no difference between air and ground tests. In fact, some people claim (in certain ground conditions) that PI detectors demonstrate a greater depth when the target is buried in the ground matrix.

[Xtrem]

This is a nice project , especially for learning and education, but let me make some changes to the
circuit.

[Qiaozhi]

This is a nice project , especially for learning and education, but let me make some changes to the
circuit.

[ATTACH]54816[/ATTACH]

Have you made and tested these changes on the original circuit?

[Xtrem]

Have you made and tested these changes on the original circuit?

Yes

https://www.youtube.com/watch?v=7M5RpMLhRrs

plus changes on the sound.

[Xtrem]

The drivers for the 4066 are not necessary, if you handle only the positive part of the signal (0 to +5V)

[6666]

The drivers for the 4066 are not necessary, if you handle only the positive part of the signal (0 to +5V)

can you draw it ?, do the 4066's turn on completely ?

[Matt_Rowe]

Yes

https://www.youtube.com/watch?v=7M5RpMLhRrs

plus changes on the sound.

Why does the sound go away when the object gets close to the coil

[Xtrem]

can you draw it ?, do the 4066's turn on completely ?

If we supply the 4066 with a single 5 volt supply
then it opens and closes normally,
but the analog signal that is managed and passes through
it, this must also be from 0 to 5v. thats why i reversed the
input signal.

[Xtrem]

Why does the sound go away when the object gets close to the coil

the sound dont go away, but we can not hear it because the high limit frequency of the VCO is
too high.

[gbrowne]

Yes, I wrote the Arduino PI sketch.

Obviously the Pico is a more powerful device than the Nano, with a lot more memory, so I might change my mind later as I get more familiar with it.

Interesting point George. As you say, the pi pico is nearly 10x faster and has ADC that can reputedly return 10-bit ADC at up to 500k/s at a push. Here's an example of a pi pico doing FFT...
https://www.hackster.io/AlexWulff/ad...pi-pico-f883dd
I'm much stronger on software/firmware than I am on hardware, so I'd be interested to see if I can digitise the interesting bits of the flyback signal and then process it in software. Strongly suspect that this sort of processing might be better done with the help of a dedicated DSP chip ? Also, it's probably unlikely that a pi pico has the grunt to keep up.

[Qiaozhi]

Interesting point George. As you say, the pi pico is nearly 10x faster and has ADC that can reputedly return 10-bit ADC at up to 500k/s at a push. Here's an example of a pi pico doing FFT...
https://www.hackster.io/AlexWulff/ad...pi-pico-f883dd
I'm much stronger on software/firmware than I am on hardware, so I'd be interested to see if I can digitise the interesting bits of the flyback signal and then process it in software. Strongly suspect that this sort of processing might be better done with the help of a dedicated DSP chip ? Also, it's probably unlikely that a pi pico has the grunt to keep up.

The RPi Pico's ADC has 12-bit resolution. At least that's what it says in the datasheet.

[Qiaozhi]

If anyone is having problems ordering a copy of the book from Amazon in their particular country, the Book Depository can supply copies with free delivery worldwide.
https://www.bookdepository.com/Ardui.../9798719427911

I will also add this information to post #1.

[6666]

If anyone is having problems ordering a copy of the book from Amazon in their particular country, the Book Depository can supply copies with free delivery worldwide.
https://www.bookdepository.com/Ardui.../9798719427911

I will also add this information to post #1.

Hi George, my book arrived earlier from the USA than expected, good job on the book nice clear schematics etc.