Bipolar PI design

[algan]

Hi Carl, if the power supply of the bipolar circuit is like in GB-PI and +12 volts will be GND, and the PIC processor is powered by -5 volts and GND, then it would be possible to use 4066 without translators, what would it work then and what would be the difference from the current one?

[boilcoil]

Thank you, Eduardo for the tests done and for sharing them in the forum. Thank you again

[eduardo1979]

Hello Boilcoil. I've tried with 74HCT4066, 74HC4066, CD4066, and CD4016. There's no difference in depth. The only difference I notice is that the Ground Balance drifts very slightly, and I have to readjust the potentiometer. The drift is minimal. I've tried with a Hot Rock.

[Detectorist#1]

Hi boilcoil,
I just assembled one simple tester for 4016 and 4066 analog switches.
The schematic is attached.
You are right - these switches have problem when voltage between input and output of the switch in ON state is more than 0.4V-0.5V. Only in the datasheets of 4016 and 4066 from TI company have at first look strange information for MAX current via switch. Other companies are silent for this problem. For 4066 max current is 1.3mA and for 4016 max current is 0.5mA according datasheets at 10V supply voltage. The reason for those difference is different resistance in ON state. After your post, I understand why this strange parameter exists in the datasheets for 4016 and 4066 from TEXAS INSTRUMENTS company. Thank you for your post!

[boilcoil]

...I've recorded ...

Hello Eduardo,
I watched the video, really good design.
I noticed that all IC are mounted on sockets, which is a good choice for hobby electronics.
In the project, you use analog switches, type 4066, which, however, have one feature that may or may not be useful, depending on the specific application.
When a positive voltage is applied to pin nY (1Y, 2Y, 3Y, 4Y) relative to the corresponding pin nZ (1Z, 2Z, 3Z, 4Z) and the drop of voltage in the on state is greater than 0.4V, then current flows to pin nZ from the power supply of the chip (with reverse polarity, this effect is not observed).
You could try directly replacing 4066 with 4016. Of course, the 4016 has more resistance in the on state, but you put serial resistors of 1k in the circuits of the incoming signals, so it doesn't matter much.
IC 4016 is much simpler than 4066, but the aforementioned effect is not observed, i.e. it is completely symmetrical. Replacing 4066 with 4016 may or may not improve detector performance.

Please try this and share in the forum.

[Carl-NC]

Thank you. It's a 2-way street, I've learned a whole lot from everybody. ITMD has been a way to put it all together and share it back.

[Detectorist#1]

Hi Carl, many of us, ITMD3 readers, are very grateful for your efforts in favor of DIY detectorists to be involved in this exciting hobby!

[Carl-NC]

The PI-GB design has virtually no reason to exist. I see no purpose... except for educational purposes.

That's the purpose of every circuit in the book.

[ivconic]

I'm on the forum every day.
But I have nothing useful to contribute to the current thread, therefore I am silent.
My Bipolar PI is waiting. Until I put the 74HCT4053; I will not be sure about the next steps.
In the meantime I've beefed up my arsenal with the Vanquish 540 and my current thoughts are in that direction.
Regarding Carl's Bipolar PI from the ITMD3 book... this detector has something I haven't seen before in other detectors in a similar category; phenomenal behavior regarding GEB.
Another project from the book; The PI-GB design has virtually no reason to exist. I see no purpose... except for educational purposes.
I think that Bipolar PI needs to be further improved only in the part of the audio behavior and possibly a little more power of "penetration" (read as "increase in depth").
As it is now; it is good for use with very small coils (20cm and below) and on very "heavy" soils.
It is good for medium and larger coins in soils that are too mineralized for other detectors.

[pechkata]

Special greetings to ivconic

[pechkata]

I'll do that next time I sit to deal with it.

Hello ivconic
What happened, bro?
Where did you run away - you're not there?
The forum is not the same without you.

[boilcoil]

Excuse me, now I read that it is a half-sine wave, so I am correcting myself.

[boilcoil]

Maybe so?

PS:I don't know physically how the individual levels of PCLK1, NCLK1... correspond to the schematic diagram, so I have simply accepted them from the description of the published source code.
Perhaps, if they refer to some of traditional schemes, the ON should be SET, the OFF should be CLR

[Carl-NC]

Hi, Carl, can you take a look at whether this source code will work correctly for half-sine, I made it for PIC16F18426

It looks like you are creating 10 positive pulses followed by 10 negative pulses. Half-sine recycles energy and requires alternating a single positive pulse with single negative pulse.

[algan]

Hi, Carl, can you take a look at whether this source code will work correctly for half-sine, I made it for PIC16F18426