felezjoo PI(the best pulse induction metal detector that I made until now)

[Detectorist#1]

Hi Aadu,
Number 1 haves too big Coss and maybe too big Cgs.
Number 3 haves too big Rds.
Number 2 is more suitable - use it for this project. For this transistor no need for additional diode in the drain.

[Aadu]

Thank you, that's clear.

[klaus3]

Hello maybe someone knows advice,
I have assembled the board and checked for possible errors without result with original parts always get error delay coil error displayed mosfet bs170 exchanged mos irf 840 also. try coil 170mm 20 windings .35mm wire diameter. At mosfet bs170 there is 5 volts at the gate and it thus controls through whereby mosfet irf 840 remains inactive.maybe someone has an idea I will wind a new coil and try again.

[MDfanatic]

What kind of PCB did you use? Homemade or manufactured? Have you checked ALL the traces to the components and made sure you have no cold-welds or unsoldered components anywhere?

[Detectorist#1]

Hello klaus3,
If on the gate of BS170 haves +5V measured by digital voltmeter, most probably the microcontroller is not programmed properly.

[algan]

The coil must be made with a 0.50 or 0.45 wire, about 440 microhenries, and for an antenna size of 28 cm, this is about 23-24 turns. Make one like this. The problem is that it does not recognize the coil, which gives you an error about the coil.

[pechkata]

The coil must be made with a 0.50 or 0.45 wire, about 440 microhenries, and for an antenna size of 28 cm, this is about 23-24 turns. Make one like this. The problem is that it does not recognize the coil, which gives you an error about the coil.

Let them find fault with the impulse.

[klaus3]

Hello everyone,
I will try to wind a new coil with 380uH, if the error delay coil error comes from there. I can also try to reprogram the Atmega 328-PU, because it outputs 5volt at pin 16 for MOSFET bs170, but I don't think this is the error, rather the coil.
Thanks in advance for the help

[Aadu]

Hello, does anyone know what three beeps in a row mean, low pitch and continuous?

[geoscash1]

Hello, does anyone know what three beeps in a row mean, low pitch and continuous?

It has quite a few different alarms. Battery low, coil error alarms for coil current and impedance low and high etc, gps & data log alarms, incorrect password etc and others. Looks to have low tones on coil errors.

[Aadu]

Thanks for the reply.
I have tried different coils, changed mosfets, it doesn't help. The control numbers are fine, the depth is good, the discrimination works. It beeps three times every 5 seconds.

[geoscash1]

Thanks for the reply.
I have tried different coils, changed mosfets, it doesn't help. The control numbers are fine, the depth is good, the discrimination works. It beeps three times every 5 seconds.

So its possible it is the calibration alarm beeping. It also has a GPS "searching" as well. Does it show anything on the LCD display?

[Aadu]

Yes, sometimes positive numbers, sometimes negative. Runs very fast, does not depend on coil movement or settings

[geoscash1]

Yes, sometimes positive numbers, sometimes negative. Runs very fast, does not depend on coil movement or settings

Its most likely the calibration after start up. It has a bunch of initialization procedures and also some test functions.

Do you have a reset or an "ok" or "enter" button? If so, power it off wait a minute or so and then turn it back on, let it do its initialize. If it still has the low tone multi beep then press and hold the ok/enter/reset button down for 5 seconds, keep the coil away from any metal and do it outside if possible and see if that works. This unit has a ton of functions and safety checks. In the code, the coil has to meet the requirements for min current and max current and min impedance and max impedance parameters too so it could be the coil causing the continuous beeps.

[Aadu]

Could it be a problem with the coil cable, I have all the coils built with speaker cable. It worked well for the Clone Pi AWR. The auto delay is 19, 390mh, 1.2 ohms.