Arduino Nano PI Main Discussion

[Qiaozhi]

OK - good luck.

[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]

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]

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

[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.

[jamespage93433]

Here is my new coil being built.

[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

[surfdetector]

I am searching insight on what exaclty to look for while adjusting r12 at (testpoint 6?!?)

Its May 2023 Bump
Greetings to all
James

This video shows the R12 adjustment.

https://youtu.be/T8EStHy71c4

[jamespage93433]

Just built this, is working awesome, but I feel there is room for improvement on my calibration skills.

Happy to see some recent posts! Bump

Kosacid - I have no response from Vol pot. Its just loud. I suspect the problem is the circuit on page 15 fig. 2-7. The potentiometer is wired more like a speaker L-pad or just different. Shows no voltage divider to +12v ,wired straight to it. The ground switched from Q5 thru R20. HEY just look at the 1k pot its wired like a resistave load, the pl5 is being fed power both ends..........that goof on your scope on both channels is the beep, its drawing a load as it is a floating ground having been wired sorta similar to dolby center channel which is the potential difference from left positive to right positive.

I am searching insight on what exaclty to look for while adjusting r12 at (testpoint 6?!?) I am using rs485 PE insulated wire for coil and the entire cable (1 pair) for coil to board connection, critical dampening achieved, working on lowering coil to shield capacitance (i sprayed it with krlon clear spray, not advised)

Its May 2023 Bump
Greetings to all
James

[kosacid]

if you look at the yellow trace you will see a slight curve i wonder if there is a short on the amp going to remove the chip holder and try again the line gose up and down when you adjust the threshold

[kosacid]

love them videoes by the way

[kosacid]

yes it is fine i built another and it is working fine but the board thats not working i striped the caps and redone the integrator still the same i get a slight curve on the scope on TP11

[surfdetector]

is there a error on the audio integrator circuit i just built this and TP10 and TP11 is not very responsive

At about the 2 minute point in my video I show what TP 10 and 11 look like as tested with my oscilloscope.
https://youtu.be/G1gUYHVw20k

[Qiaozhi]

is there a error on the audio integrator circuit i just built this and TP10 and TP11 is not very responsive

There is definitely no error in the ANPI design.

[kosacid]

is there a error on the audio integrator circuit i just built this and TP10 and TP11 is not very responsive