Arduino Nano VLF Metal Detector Project - Main Discussion

[Ronin0000]

The arduino nano that I am using is not a offical one. Should I buy a offical one and test it with the circuit?

[kosacid]

ok np its just i have dyslexia i have a reader on my mobile its just easy if its a ebook i didnt know there was a problem with it

[Qiaozhi]

is there a ebook version ? i only seen the paper one forgot to say add the U8g2 library for the oled

There is no ebook version, and there never will be.
The encryption on KDP's ebooks is too easily circumvented by hackers.

[kosacid]

is there a ebook version ? i only seen the paper one forgot to say add the U8g2 library for the oled

[Qiaozhi]

Here is an update:
I have recived new LT1054 chips from a diffrent supplier, but unfortuantly that did not solve the problem.
I have wired the circuit standalone on a breadboard to see if my pcb was messed up, but that also did not solve the problem and the results are the same.
All of the components have been replaced at least once, and the sync pulse appears to be working when I check it through a oscilloscope.

I have tried Gunghouk's suggestion of temporarily removing the sync pulse, but that also did not change anything.

I am a little bit stumped at the moment.

Any tips would be appreciated.

Thanks

That's very strange.
However, I can assure you that it definitely works.
One thing that strikes me as a bit odd is that you measured the +5V from the Arduino is only 4.72V.

[eduardo1979]

IC sockets can sometimes have a problem. I had this happen to me a while ago, because I bought some turned sockets and they were of poor quality. You should also check the soldering of the electronic components, because this factor is very important.

[Ronin0000]

Here is an update:
I have recived new LT1054 chips from a diffrent supplier, but unfortuantly that did not solve the problem.
I have wired the circuit standalone on a breadboard to see if my pcb was messed up, but that also did not solve the problem and the results are the same.
All of the components have been replaced at least once, and the sync pulse appears to be working when I check it through a oscilloscope.

I have tried Gunghouk's suggestion of temporarily removing the sync pulse, but that also did not change anything.

I am a little bit stumped at the moment.

Any tips would be appreciated.

Thanks

[Qiaozhi]

Since both -12V supplies are not working, then I suppose it's possible that U2 and U3 are faulty/fake.

However, I would try this first:
1) Remove U2 from its IC socket. You will need to leave U3 in circuit to generate VREF.
2) Check the SYNC pulse at the collector of Q1 (2N3904) is correct using an oscilloscope. (I note you've already checked that the Nano is generating the SYNC.)
3) If SYNC pulse looks OK, then try replacing U2 with an LT1054 from another supplier.

My suspicion is that Q1 is faulty.

[Gunghouk]

Hi Ronin, I've found issues with the LT1054 similar to yours but on the Voodoo, ie no negative supplies. Try lifting pin 7 of the IC out of its socket and see if theres any change .I used that temporary solution for a while until I placed a 100pF cap between the collector of the sync transistor and pin 7, the same as on the Minipulse Plus, but you'll need to do it for both LT1054.
Just to point out that both circuit variants produce the -12v output in LTspice with 1kHz sync, though with the 100pf cap the output settles faster. Go figure.
Good luck

[Ronin0000]

I'm having trouble getting the voltage converters on my circuit board to work. I've built the converters exactly as shown in the diagram, but I'm unable to get the negative voltages to function properly. I've double-checked that all components are functioning, correctly placed, and are the right ones, but I still can't pinpoint the issue.

I tested the Arduino Nano's voltage output, which reads 4.72 volts—close enough to 5V. All the negative voltages seem non-functional, so I suspect the LT1054 chips may not be working. The 5V and 12V outputs are fine, but the negative voltages are not.

I verified the code is sending a sync pulse to the chips, and I've measured the input voltage (VCC) on both LT1054 chips, which shows 12V. However, the Vref is reading 1.7 volts, and the Vout shows a very small voltage that seems incorrect. None of the negative voltage test points register significant voltages.

Any suggestions or ideas would be greatly appreciated.

Thanks, Ronin

[Qiaozhi]

Here are the simulations files, plus a spreadsheet to calculate the R-2R ladder values.

[Qiaozhi]

Hi I love the project and I am currently sodering the circuit board. I was wondering if there were any LTS Spice simulation files so I could try my own experiments without having to physiclly build them or create the simulation from scratch.

Thanks, Ronin

I'm away from home at the moment, but can check for you at the end of the week.

[Ronin0000]

Hi I love the project and I am currently sodering the circuit board. I was wondering if there were any LTS Spice simulation files so I could try my own experiments without having to physiclly build them or create the simulation from scratch.

Thanks, Ronin

[Qiaozhi]

Hi

Just purchased (and awaiting) both the Arduino PI and VLF books from George.
On a less technical note (and apologies if this is detailed in the books) but have the enclosures (VLF display) and choice of shaft also been discussed?
I can imagine the PI being a bit easier (no display) with everything being done a panel and box site like Schaeffer.
I was thinking more of the VLF LCD display.

Apologies if this is all in the books but I am just getting a bit excited!

Best regards
Richard

There is some brief information on pages 111/112 in the VLF book, but the mechanical construction is mainly left to your imagination.
Chapter 4 of the PI book has more detailed information on the enclosure.
The Voodoo project has Chapter 4 dedicated to the mechanical construction.

[BigDutch]

Hi

Just purchased (and awaiting) both the Arduino PI and VLF books from George.
On a less technical note (and apologies if this is detailed in the books) but have the enclosures (VLF display) and choice of shaft also been discussed?
I can imagine the PI being a bit easier (no display) with everything being done a panel and box site like Schaeffer.
I was thinking more of the VLF LCD display.

Apologies if this is all in the books but I am just getting a bit excited!

Best regards
Richard