Arduino Nano PI Main Discussion

[jamespage93433]

Thanks for the link!

I had gotten the volume pot wired wrong, fixed it.

Tried taking my round coil off the former and made it an oval shape but now getting ripple from preamp, didnt readjust the dampening resistor, so decided to build new coil.

Almost done with the physical contruction of the shaft,pole,armrest and grip. Started with electronic under armrest, too heavy, going to sling pack electronics/batt/knobs or fanny pack
There were some silkscreening errors that needed fixing.

Hope to finish shaft,coil holder ,armrest and take pics today.

James

[jamespage93433]

Here is my new coil being built.

[yoyo27983]

Does anyone have a link to the project pcb on JLCPCB?
I would like to order a few boards.

UPDATE> I just ordered them! for $2 for 5.

[nogi]

I'm a metal detector amateurs and my electronic knowledge is not very good, I'm reproducing this project, but I'm having difficulties, when I measure the TP6 waveform,I found that it's not good, and there is almost no induction for coins.Is it because the inductance of my coil is too small.

I'm using a coil calculator to figure it out. It's 26AWG,210mm diameter, 25 turns

[Qiaozhi]

According to the values given, your coil should be about 403uH, so that's not the problem.

Is the single pulse shown on your scope the main sample pulse?
If so, you appear to be sampling before the preamp output has settled.
What is your timebase setting?

Also, you have made the rookie mistake of building the whole detector and not testing each stage as you go along.

[nogi]

George, thanks for the advice you gave me.
The single pulse is the output of the TP5, the time base setting in my diagram is 100us.
To correct my mistake I went to watch the surfdetector's videos and rebuild the board.

When testing the TP6 output I did not add the damping resistor, comparing it to the results in his video, I found that the expansion of my waveforms was too long (timebase setting is still 100us).

So I think my homemade coils might not be good enough, I'll make a new one and check that again.
Thanks again for the help.

[Qiaozhi]

OK - good luck.

[phred01]

has anyone got a spare PCB to sell saving me to have them made plse PM me

[Gunghouk]

Hi all I'd like to offer my slicked up version of the software sketch for the ANPI detector. I think the changes will go a long way to eliminatiing jitter caused by excessive software times and system noise jitter on the potentiometer.

I'm hoping to try this version out on some lower spec arduino boards to see how they cope.

The pot currently gives about an extra 126 uS on top of the default 10uS. This can be halved to 63uS with a simple mod to the sketch.

Please share your experiences good or bad.

Cheers

arduino_PI_Fast.zip

[SaltyDog]

Hi Guys,

Can anyone point me to a complete parts list for the project.

Many Thanks

[Qiaozhi]

Hi Guys,

Can anyone point me to a complete parts list for the project.

Many Thanks

The Component Parts List is in Appendix A of the book. -> Arduino Nano Pulse Induction Metal Detector Project - Published March 2021

[SaltyDog]

Hi, yes I realize that, however I don't need the book, I am happy to assemble and test without it ..

[SaltyDog]

Qiaozhi Hi, I have successfully built the board and have good target distances .... e.g gold ring at 30cm (This is with a mono coil bought off ebay 430uH)

Many thanks for the well designed project. I will be looking at adding further code to the Arduino to implement simple discrimination,
I am thinking along the lines of automatic variation of the delay at various increments, then sample the results to identify pull-tabs/foil etc. Then light a good/bad LED.

[Qiaozhi]

Qiaozhi Hi, I have successfully built the board and have good target distances .... e.g gold ring at 30cm (This is with a mono coil bought off ebay 430uH)

Many thanks for the well designed project. I will be looking at adding further code to the Arduino to implement simple discrimination,
I am thinking along the lines of automatic variation of the delay at various increments, then sample the results to identify pull-tabs/foil etc. Then light a good/bad LED.

Well done.
The Arduino Nano PI is one of my favourite projects because it works extremely well and is simple to construct.
Good luck with the modifications.

[pito]

is there a video ?