Superscan PI

[nasios]

Hello, my MOSFET is very hot, and the heatsink is generating high voltage, making a hissing sound. I think it's a coil overload issue. The DeepScan coil rating of 500uH and 1.2R should be correct; I'm not sure if this also applies to a 30cm coil. My coil measurement shows 520uH, and the inductance setting should have at least a 20uH error. Could you please provide your suggestions? Thank you very much.
https://youtube.com/shorts/exaYanBR2...noXnhIPQ1pzxt6

Hello ZOUjiarui, Would you be willing to share the schematic and PCB files? I'd love to build one myself so we can test it and explore it together.

[GeoMax]

Hi ZOUjiarui,

my suggestion to you is get an oscilloscope and learn how to use it. Then you can find every wrong settings of your detector.

[Op04]

When we set pulse width to big, ended up with dead FET (if it's too hot) , we need to understand each section first. I did superscan not directly clone but modified minipulse to get working at 24V, with similar parameters timing freq, pw, etc It took time and no one will guide, i will not recomended to build, coz there's no real proven working schematic

[ZOUjiarui]

Hello, my MOSFET is very hot, and the heatsink is generating high voltage, making a hissing sound. I think it's a coil overload issue. The DeepScan coil rating of 500uH and 1.2R should be correct; I'm not sure if this also applies to a 30cm coil. My coil measurement shows 520uH, and the inductance setting should have at least a 20uH error. Could you please provide your suggestions? Thank you very much.

https://youtube.com/shorts/exaYanBR2DA?si=xvnoXnhIPQ1pzxt6

[GeoMax]

Hello,

The frequency setting is of course important. Many other timing parameters are also responsible for the entire circuit's functionality, whether your circuit works or not. These settings can only be checked with an oscilloscope. A very inexpensive oscilloscope is perfectly adequate and not at all expensive. The cheapest ones are available for under 50 euros. Handheld oscilloscopes can be found on Amazon starting at 100 euros.

[ZOUjiarui]

Hello, the frequency of the MK2 version is adjustable, and I don't think 90Hz is that important. I replaced the chip; the 709 outputs 0V, and the sound after threshold adjustment seems normal. It squeals when the coil is touched, which I think might be due to coil mismatch. Please give me more help. Thank you very much.

[GeoMax]

Hi Nasios,

It's good to have these parameters. However, without an oscilloscope, it's difficult, if not impossible, to adjust them. You also need to fine-tune the pulse width and other timing parameters to the correct values. Without an oscilloscope, that's simply not possible. It's like trying to watch your favorite TV show without a television. It just doesn't work.

[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

[GeoMax]

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

[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]

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?

[Op04]

.

[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]

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

[ZOUjiarui]

https://youtube.com/shorts/eeS-h0GzgI4?is=o8st4VSdhcMu3wsh