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

[sabios]

They believe that this type of resistance works since the metal film here in Mexico is very difficult to achieve, only these.

[sabios]

Well I solved it now the detector already works but now another question that coil recommend me to ask since I made a cat5e and the truth is its detection is very poor, which is why they recommend me and which magneto cable to buy the AWG 24 or which one since here in Mexico they are only achieved that way. that while I wait for the resistance that I am going to send to ask for other lf357n.

[sabios]

I finished the detector but I noticed that it has too many errors for example, all the time it is ringing even with the sensitivity to 15 I have to lower it to 10 so that nothing sounds and the arrest is somewhat poor a soda can detects it to me more or less 40 or 50 cm is correct so I already check with different configurations and nothing for sure I made a 50 coil and a 70 cm coil with the 70 one it detects the can at about 55 cm it is little or so it is fine but I have to lower it sensitivity too much.


tomorrow I will upload photos and videos.

[Emersonpaz]

What is the coil configuration?

[sabios]

I have tried with different configurations and nothing is too unstable, on the other hand I do not know if it is because I am using version 3.35 full and I read that it is very unstable and that with version 3.35 with a counter it is better, it is true.

[Emersonpaz]

I tested both versions with and without a counter, I didn't notice any difference between them,
I made the coil to specification using 0.8mm in a 20cm outer and 12.5cm spider shape inside but found it unstable with a thinner 0.5 awg24 wire in a 25cm outer shape is much better. simple winding

[ZOUjiarui]

https://youtube.com/shorts/fQqZWBZr7rg?feature=share
Fpi1x1m coil test
Iron machete detection is less than 1 meter, detection distance is about 70 cm.

[sabios]

My question is according to the issue what is the damping resistance that describes that of 470R.
https://www.geotech1.com/forums/show...506#post224506

[sabios]

a question what would be the voltage of the bs170 in its legs and what would be that of the rf840

[sabios]

what would be the operating voltage of this, because it gives me 0volt in R6

[Carl-NC]

R6 will have a pulsed waveform between 0V and 12V, if that is the question. You will need an oscope to see it. The BS170 has a 5V pulse on the gate and a 12V pulse on the drain.

Also, I would recommend putting the 5k pot in series with R11. Otherwise, if you set the pot to 0 you will probably blow the diodes and then blow the opamp.

[sabios]

check and at the output of the bs170 in drain there is only 6 to 7 volts for the same reason in R6 there is only 7 volts and not the 12v at the input of the gate to the irf840. any replacement for the bs170

[Carl-NC]

1. Is the 12V supply working?

2. Is there a 5V/0V pulsed waveform at the gate of T1?

[sabios]

I corrected check and at the output of the bs170 in drain there is only 0.66 volt and I already checked the resistance R5 and 12 volts enter, and in gate I have 5 volts by the way change the bs170 for another check it with the LSR tester to make sure it was good.

so what would be a good replacement for the BS170.

[Carl-NC]

It sounds like you do not have a pulse signal on the gate of T1. Changing T1 will not fix this.