PICKINI V4 - an easy to build, self adjusting PI detector

[Altra]

Nice job! You should put it in a tube and make a walking stick metal detector.

[Olly]

More than a year ago I did a tiny SMD version of the board, today I finally got around to building and testing it.


It's only 50mm x 30mm.
Here it is next to a Pound Coin.
Works great with V4.2 of the hex file.

Thanks for a great design Bernard.

[mc_307]

I don't have a Sprint layout, only an Eagle layout used at the time.
There are some references in the thread to Sprint - maybe some other forum member has a Sprint layout
https://www.geotech1.com/forums/foru...745#post224745

The hex file to use is indeed this one:
https://www.willaert.world/MD/softwa...Pickini4.1.hex

I used PicKit3 to program the device, but there is a remark from Qiaozhi here that should make it possible to also use PicKit2:

https://www.geotech1.com/forums/forum/technology/pi-technology/13867-pickini-v4-an-easy-to-build-self-adjusting-pi-detector?p=224189#post224189

There is also a reference to PicKit2 here:

https://www.geotech1.com/forums/forum/technology/pi-technology/13867-pickini-v4-an-easy-to-build-self-adjusting-pi-detector?p=225008#post225008

Thank you. I was confused when there were many options in the software section. I think uploading a single file is enough. Can additions be made to the software? For example, a ferro-nonferro LED indicator? I also saw a video on Youtube, he made a pinpointer with a coil removed from an old CRT TV and the distance was very good. Do you have any information on this?

[Toros]

Anyone who doesn't have Sprint Layout can download it from here.
https://yadi.sk/d/SYFxFJd9gy5BA
The link is old, but it still works. Click on the arrow. Free.

https://disk.yandex.ru/d/BVyhF3eVj5y8Y

[BC547]

I don't have a Sprint layout, only an Eagle layout used at the time.
There are some references in the thread to Sprint - maybe some other forum member has a Sprint layout
https://www.geotech1.com/forums/foru...745#post224745

The hex file to use is indeed this one:
https://www.willaert.world/MD/softwa...Pickini4.1.hex

I used PicKit3 to program the device, but there is a remark from Qiaozhi here that should make it possible to also use PicKit2:

https://www.geotech1.com/forums/forum/technology/pi-technology/13867-pickini-v4-an-easy-to-build-self-adjusting-pi-detector?p=224189#post224189

There is also a reference to PicKit2 here:

https://www.geotech1.com/forums/forum/technology/pi-technology/13867-pickini-v4-an-easy-to-build-self-adjusting-pi-detector?p=225008#post225008

[mc_307]

Hello my friend. Is there a sprint layout file for pickini v4.1? Also, is it enough to load the file named "Hex for Pickini4.1 - initial comparator offset value read from EEPROM = faster calibration" in the software section? I will load it with pickit2, can you give me an instruction to follow?

[BC547]

To compensate, you need to increase the sensitivity, which means increasing the consumption again

Increasing the sensitivity only results in accumulating more temporal measurements in software ( flyback pulse widths).
It does not change the pulse width, nor the pulse frequency. Hence, power consumption remains the same regardless of the sensitivity setting.

[Toros]

There is a problem, forum members, with this device. The problem is that the sensitivity begins to decrease gradually on its own, even though the battery is still fully charged. Does anyone here explain the problem to us?

If you look at the detector circuit, you will immediately see what is the reason for the decrease in the detector's sensitivity. The circuit is powered by 12 volts of voltage, but there is no voltage stabilizer. You say that the battery is still charged, but this is not exactly the case. When the detector consumes 130 mA, the battery voltage constantly drops, which leads to weaker signals compared to those from a few minutes ago. To compensate, you need to increase the sensitivity, which means increasing the consumption again. And so things move in a closed circle. If you looked at the first detector circuits, those with the PIC 16F616, you will notice that there was a 12 volt voltage stabilizer provided. Due to the high consumption of the detector, this stabilizer quickly heated up and the heat had to be removed with a radiator. As far as I remember, someone on the forum suggested removing the stabilizer and supplying power to the circuit directly. In subsequent schemes, this stabilizer was dropped and the problem of reducing sensitivity remained.

[useus]

I had not noticed your attachment = audio file yet.
When listening to it, this sounds like the coil error sound. If you connect a headphone to the audio output, you will here a much lower intermittent tone than the one generated by the beeper.
Can you switch the detector on without the coil connected. It should give the same error sound then.
If that is the case, something is wrong with the TX side.

EDIT:
I just tested the coil error sound and this is a continuous low frequency sound.
Not intermittent like in your audio file.

After power on, you first hear the welcome sound.
Then a calibration procedure start during which you hear the 0.5 Hz confidence tick.
When calibration is finished, there is a start sound.
Then, the confidence tick - or detection sound can be heard.

Can you try with a regular headphone first.
If that is OK, connect the 5V beeper to pin 7 of the PIC.
This will not offer all tone varieties as with the headphone output, just a target detection.

sorry, I made a mistake, I connected it to pin 11, connecting it to pin7 remains mute during calibration (it's not a problem), then it works correctly in both motion and non-motion.

My mistake during the assembly of the PCB, sorry again and thanks for the help

[useus]

I had not noticed your attachment = audio file yet.
When listening to it, this sounds like the coil error sound. If you connect a headphone to the audio output, you will here a much lower intermittent tone than the one generated by the beeper.le tensioni sono abbastanza simili, le mie leggermente piu alte, specialmente su lm318. Si ho provato senza coil e fa lo stesso suono
Can you switch the detector on without the coil connected. It should give the same error sound then.
If that is the case, something is wrong with the TX side.

EDIT:
I just tested the coil error sound and this is a continuous low frequency sound.
Not intermittent like in your audio file.

After power on, you first here the welcome sound.
Then a calibration procedure start during which you hear the 0.5 Hz confidence tick.
When calibration is finished, there is a start sound.
Then, the confidence tick - or detection sound can be heard.

Can you try with a regular headphone first.
If that is OK, connect the 5V beeper to pin 7 of the PIC

the voltages are quite similar, mine slightly higher, especially on lm318. Yes, I tried it without coils and it makes the same sound.
with coil after calibration the detection works but it continues to make that sound
the buzzer is already connected to pin 7
even disconnecting r9 same problem

I'll try it as soon as I find some headphones

[BC547]

I had not noticed your attachment = audio file yet.
When listening to it, this sounds like the coil error sound. If you connect a headphone to the audio output, you will here a much lower intermittent tone than the one generated by the beeper.
Can you switch the detector on without the coil connected. It should give the same error sound then.
If that is the case, something is wrong with the TX side.

EDIT:
I just tested the coil error sound and this is a continuous low frequency sound.
Not intermittent like in your audio file.

After power on, you first hear the welcome sound.
Then a calibration procedure start during which you hear the 0.5 Hz confidence tick.
When calibration is finished, there is a start sound.
Then, the confidence tick - or detection sound can be heard.

Can you try with a regular headphone first.
If that is OK, connect the 5V beeper to pin 7 of the PIC.
This will not offer all tone varieties as with the headphone output, just a target detection.

[BC547]

Also check all other DC voltages as described here


All voltages measured with a battery voltage of 12.0V:

• U1 - PIC16F1824
  PIN 1 : 5.0V
  PIN 2 : 2.7V
  PIN 3 : 1.2V - sensitivity potmeter
  PIN 4 : 5.0V
  PIN 5 : 4.7V
  PIN 6 : 0.1V
  PIN 7 : 0.0V
  PIN 8 : 3.7V
  PIN 9 : 3.7V
  PIN 10 : 2.7V
  PIN 11 : 0 ..5.0V - audio
  PIN 12 : 2.8V
  PIN 13 : 2.0V
  PIN 14 : 0.0V
  
  IC4 - LM318 opamp
  PIN 1 : 9.5V
  PIN 2 : 6.8V
  PIN 3 : 6.8V
  PIN 4 : 0.0V
  PIN 5 : 4.8V
  PIN 6 : 7.4V
  PIN 7 : 11.9V
  PIN 8 : 1.4V

[BC547]

Low battery detection ?
Voltage divider R8/R9 on the power supply is the battery voltage input for the PIC.
This should result in about 2.8V on pin 12.
When you disconnect R9 = 10K, the battery voltage detection will no longer work and should always be OK

[useus]

At the audio output, a pulse is generated every 2 s = confidence tick. This indicates that the detector is up and running, even when no target is detected over a long period of time. It is common with military detectors.
When you connect a 5V beeper to the audio output it will be activated every 2s.
Better would be to connect a piezo speaker instead of a 5V DC buzzer.
If you insist on using this buzzer you can connect it to pin 7 of the PIC. This is a digital output that goes high when a target is detected.
It is ON/OFF, there is no gradual increase of the "tick" from 1Hz to 1kHz as you have on the audio output.

An additional sound not mentioned here is the "coil error sound", about the same as low battery sound. But this would mean that there is something wrong with the coil/front-end and no flyback pulse is detected.
Since you mention "the detector works", this can not be the case ?

All sounds can be found here:
http://www.willaert.world/MD/pickini...technical.html

the problem is that it is not the tick sound like on the site, I already checked, it is a long sound. could it be a problem in the circuit? for example I used irf840 instead of irf740.

Yes, the target marks it for me, it's not a coil problem since on another detector it doesn't give me problems.

I tried 4.1, same problem

https://files.fm/u/gnw8zq6m89

[BC547]

At the audio output, a pulse is generated every 2 s = confidence tick. This indicates that the detector is up and running, even when no target is detected over a long period of time. It is common with military detectors.
When you connect a 5V beeper to the audio output it will be activated every 2s.
Better would be to connect a piezo speaker instead of a 5V DC buzzer.
If you insist on using this buzzer you can connect it to pin 7 of the PIC. This is a digital output that goes high when a target is detected.
It is ON/OFF, there is no gradual increase of the "tick" from 1Hz to 1kHz as you have on the audio output.

An additional sound not mentioned here is the "coil error sound", about the same as low battery sound. But this would mean that there is something wrong with the coil/front-end and no flyback pulse is detected.
Since you mention "the detector works", this can not be the case ?

All sounds can be found here:

http://www.willaert.world/MD/pickini_en/V4/technical.html