Hybrid Bipolar Detector

[pechkata]

Some timings of Hybrid Bipolar Detector:

We did not see bipolar impulses.

[pechkata]

That's a square wave PI, not half-sine. Completely different approach.

It's a half sine.

[Altra]

It's a half sine.

There is a difference. The half-sine in the CCPI represents voltage. The half-sine in a THS pi represents current. As Carl stated it is a whole different concept.

[pito]

@pechkata

Does your detector have a discrimination? What is the detection range for coin, on video it is hard to see ?

[pechkata]

Hi Altra
I didn't mean the broadcast.
I meant the pumping timings.
Something like that.

[pechkata]

@pechkata

Does your detector have a discrimination? What is the detection range for coin, on video it is hard to see ?

There isn't one yet - it's a project.

[pito]

This is how I'm doing presentation, can you show test for iron and aluminium, just this two objects ?
https://www.youtube.com/shorts/CcuXwZVsfNo

[Carl-NC]

The project in this thread has a bipolar truncated half-sine current like this:


The Deemon project has half-sine flyback voltages but a square-wave current. Completely different; if you want to discuss the square-wave approach please use another thread.

The benefits of bipolar pulsing have been discussed in numerous previous threads; see post #27 for 2 of these reasons.

[Detectorist#1]

Hi,
I just finished the tests of the last variant of the power supply board for "Hybrid Bipolar Detector". As usual, some changes was made. Using of LM337T as constant current source is not good idea. They have parasite generation. Good old idea for using a simple transistor for this purpose works perfect. Also, for the voltage sensing TL431 is not possible to be used in this case. The current in control input is too big (5uA) and current via the resistor divider will complete discharge the accus very quickly. The TLV431 haves control current of only 0.5uA (max value). This allows to not use the MD for appr. 5 years without full discharge of the accus. My aim was to use as charging source my AC/DC adapters from my old laptops with 19V to 20V output voltage. Also, no problem to be used standard AC/DC adapters with 24V output voltage and more than 100mA output current.
The scheme of this "Power Board with Charge" is attached.

[Detectorist#1]

Hi,
It is clear that hybrid technology for MD haves good potential for developing. With adding of additional sampling signals and analysis of X and R signals in the sinusoidal part of the TX signals, is possible to achieve more good discrimination - not only "IRON CHECK". But this will need adding of many hardware stages in this project. Now, with using of power DSP chips with many ADCs for post processing of the signals, using of pure hardware solution will be step back. I hope, some of DIY people familiar with DSP's using, will improve this project.

[pito]

Hi,
will improve this project.

I can help you on that using esp32.

[pito]

There isn't one yet - it's a project.

which schematic you are using ?

[Detectorist#1]

Hi pito,
First, tank you for your announce for help for improving of this project! I read the datasheet of ESP32 and I have one apprehension - from the initial variant (V1.0) from 2017.02 to the last variant (V5.2) from 2025.11 the times between variants are between 1 and 9 months. Have probability for the firmware variants to be endless. Please, correct me if I'm not right.

[pito]

I'm talking about this one
https://www.aliexpress.com/item/1005...7cc418021wrHIQ

[gdane]

Now, with using of power DSP chips with many ADCs for post processing of the signals, using of pure hardware solution will be step back. I hope, some of DIY people familiar with DSP's using, will improve this project.

New to this forum and in search of the best open PI design to start with for a DSP-based detector. I would love to be involved in building out the digital side of this project. I currently have a STM32H7 on the way. It's the best widely supported MCU with high performance ADCs that I have found so far. External ADCs may ultimately be required, but this seems like a reasonable place to start IMHO.