Superscan PI

[GeoMax]

Hi Hassanp,
I don't have a working circuit board. But I've looked at the various schematics here in these posts and they look good at first glance. I couldn't see any obvious errors like you see in other circuit diagrams on the internet. I have not checked every IC pinouts. Many times people write wrong pin numbers at the ICs in the drawing. Have you checked them aginst the manufacturers datasheet?

[profesor]

I am asking friends who have succeeded in building this circuit to help my circuit work and I will give a great project for free to a friend who helps.

I assume you have the necessary measuring instruments to operate this circuit.
oscilloscope .multimeter etc.
1-Before connecting the coil, check the +5v,-5v,-12v,-24v lines. Are there the required voltages?
Check the 3rd leg of the 2-pulse generator 555. See the approximately 90hz pulse signal on the oscilloscope.
3-Make a test coil of approximately 380uh 2R 20cm in diameter and connect it to the circuit with an RG58 cable.
If you have assembled the 4-circuit correctly, connect the TX end and RX end with the coaxial cable.
5-Connect the first channel of the oscilloscope to the output of LM 709.
6-If everything is OK, you will see the signal. Adjust the signal so that GND is in the middle with a 100k trimpot.
Connect the second channel of the oscilloscope to the output terminals of the 6-4538s and see the sampling signals.
7-If everything is correct so far, you should see the metal detection signal on pin 7 of the TL072 opamp on the second channel of the oscilloscope.

[Hassanp]

Hello, my dear friends, thank you for your reply. I have the frequency of 90 Hz on the base 3 oscillator and the base voltages are 5 volts positive and 5 volts negative, 24 volts positive and 12 volts negative on the board and there is no problem. I will inform

[nasios]

The drawing is custom made for Qiaozhi

Hello, you have the complet schematic and the other part?

[ZOUjiarui]

The voltage should be between 4.8 and 4.9 ohms for normal operation.

[ZOUjiarui]

There was no smoke or significant heat generation; awaiting coil testing.

[ZOUjiarui]

Hello everyone, I need help from those who have successfully obtained the desired sensitivity. I'm unable to achieve the highest sensitivity setting. The inductance is approximately 520uH, 1.2R. Thank you very much.

[ZOUjiarui]

https://youtube.com/shorts/eeS-h0Gzg...st4VSdhcMu3wsh

[Op04]

You need to start with desired coil diameter first and then adapted R damp for that coil, try to lower inductance/turn this part to me was painful

[Op04]

Sorry i can't remember exactly wheter to give more or reduce turn i thrown so many many coil back then.... anyway after it done at 2 meter for 1m coil on the field in some areas if it hits large wall below (a brick wall left under the ground i don't know why but it make sound) after bring excavator to dig it.. since then I moving to modern which have gb part

[Op04]

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[GeoMax]

Hi ZOUjiarui,

I think the coil induction is to high and the damping resistor is not right for your coil. I would reduce the inductance to about max. 350uH and adjust the damping resistor accordingly. If you need more power you can increase the TX pulse width slightly.
What are your parameter for TX, sampling and sampling width, delay etc?

[ZOUjiarui]

Hello, I don't have an oscilloscope, so I can't monitor the waveform frequency at the moment. Its voltage is ±4.9V, but at -12V it only registers 11.7V. It seems very sensitive to static electricity; if a finger is near the audio jack or the coil, it causes interference. I'm trying to resolve this issue. The metal detection isn't working properly yet.

[GeoMax]

Oh,.... If you want to fine-tune your detector, an oscilloscope is an indispensable tool.

[nasios]

Hello, I don't have an oscilloscope, so I can't monitor the waveform frequency at the moment. Its voltage is ±4.9V, but at -12V it only registers 11.7V. It seems very sensitive to static electricity; if a finger is near the audio jack or the coil, it causes interference. I'm trying to resolve this issue. The metal detection isn't working properly yet.

Hello, you have to 90hz the 555 and i think in the schematic write the coil 480uH 1.2R