Bipolar PI design

[GeoMax]

Hi Algan,

why don't you just draw your own circuit board? Then you can make any changes you want and you don't have to rely on the work of others.

[algan]

yes, but the Carl Gerbers are with a program that I didn't draw and I can't convert them to Sprint Layout or EasyEDA for correction, and in your post #54 the mask is drawn by hand, that's why I asked, I thought you had a file that you can do correction.but there are no problems, I started to delete the top layer, it's slow, but it will be as Carl said, I need sound correction and someone else

[ivconic]

I don't have it without ground planes.
Here is the original Carls files (gerber):

https://www.geotech1.com/forums/forum/inside-the-metal-detector-aa/itmd3/pi-designs/430863-bipolar-pi-design

[algan]

Hello ,Ivconic can you post the lay shape of the board without the solder mask that you drew I want to make some corrections before I release the boards.. Thanks.

[ivconic]

Thanks anyway.
A friend sent me PIC from abroad.
PCB's will be done soon.
So I am not giving up, with or without video.
I think it is splendid example for future upgrades and improvements.
So, if you have; time do the video, if not; not a problem at all.

[Carl-NC]

Sorry, I took the circuit down. If I get time later today I'll set it back up.

[ivconic]

I have completed testing the Bipolar PI design and posted new firmware. I changed the timing to use 1 timer and is now all interrupt-driven, there are no polling delays. This gives the delay adjustments more resolution and more consistency.

Two things I don't like about the design. One is that the demods are a bit glitchy in that they pass through some transients. I don't know if this is a particular problem with the 4316 switches or what. I have not seen this in other designs I've done. Second is that the audio is not all that great. The 555 VCO does not have as much frequency range as I recall from when I breadboarded the circuit. And the transient glitches from the demods gives the audio a little it of a raspy sound. With a little tinkering, both might be solvable but I don't have the time right now.

Simple 10 seconds video of what you described?

[Carl-NC]

I have completed testing the Bipolar PI design and posted new firmware. I changed the timing to use 1 timer and is now all interrupt-driven, there are no polling delays. This gives the delay adjustments more resolution and more consistency.

Two things I don't like about the design. One is that the demods are a bit glitchy in that they pass through some transients. I don't know if this is a particular problem with the 4316 switches or what. I have not seen this in other designs I've done. Second is that the audio is not all that great. The 555 VCO does not have as much frequency range as I recall from when I breadboarded the circuit. And the transient glitches from the demods gives the audio a little it of a raspy sound. With a little tinkering, both might be solvable but I don't have the time right now.

[Carl-NC]

Hi Carl, would this schematic work with DD antennas Minelab GP, SD, and GPX ? Thanks.

Yes.

[algan]

Hi Carl, would this schematic work with DD antennas Minelab GP, SD, and GPX ? Thanks.

[ivconic]

[Carl-NC]

Probably, yes.

[ivconic]

I have just posted the C source code and the hex file here.

Until You confirm that you hardware is working alright; I think we should still wait, right?

[Carl-NC]

Hi, Carl, can you post the hex file if it is complete of course. Thanks.

I have just posted the C source code and the hex file here.

[Detectorist#1]

The voltages on negative inputs of IC7a and IC7b have to be zero and no chance to be amplified further.