Replies to Minipulse Plus

[Qiaozhi]

Yes it is. There is no problem on step 8 treshold pot voltage is between -3.9 and +4,1.
So do you have an Idea on what could be wrong on audio stage ? Capacitor I used are polypropyl?ne and resistor are 1% 0,5w all tested before soldering to pcb.

It's very difficult to debug a design remotely. Maybe it's not actually a problem in the audio stage.
Have you checked that the main sample and EFE samples are in the correct positions and the same width?
Can we see scope images at each stage?

[Tibuck19]

Could this issue be cause by the power? are you using a bench top power supply or batteries? i have one of those cheap no good china made bench power supply, and i can not use it when assembling and testing MD kits i get all kinds of ringing and odd behavior, however when i use actual batteries the detectors are fine. Actually if im not maskaken Qiaozhi was the one that had suggested that solution to me a while ago.

[Albdelafar]

Hi Tibuck19,
I don't think this is my issue because power is from an 4s2p accu with a tension regulator put to 12V.
To George,
ok no problem i will put pictures of sample timing asap.

[Albdelafar]

There it is all samples measurements !! to my mind all is right.

[Qiaozhi]

There it is all samples measurements !! to my mind all is right.
[ATTACH]54729[/ATTACH]
[ATTACH]54730[/ATTACH]
[ATTACH]54727[/ATTACH]
[ATTACH]54728[/ATTACH]

Things mostly seem to be correct, except that the TX pulse width is only 44us, whereas the suggested pulse width in the Build Document is 400us.
Your TX pulse rate is also slightly lower than the suggested 125pps.

Can you also post an image of the preamp output?
Set CH1 = TX OSC (TP2)
and CH2 = preamp output (TP3)

[Albdelafar]

On the first screenshot I have the main sample delay (TP6) put to is maximum (44us) on CH1 and TX pulse (TP2) set to 340us on CH2.TX pulse period was set to 9ms.
You can see here CH1 to TP2 and CH2 to TP3.

[surfdetector]

On the first screenshot I have the main sample delay (TP6) put to is maximum (44us) on CH1 and TX pulse (TP2) set to 340us on CH2.TX pulse period was set to 9ms.
You can see here CH1 to TP2 and CH2 to TP3.

From the image of your preamp output TP3, it does not seem like you have a coil attached.

[Albdelafar]

Well analysed surfdetector yes it is. I disconected the coil to avoid a maximum of interf?rences. By the way my buzzer ring with or whithout coil when audio treshold is superior to -1.3V.

[Qiaozhi]

Well analysed surfdetector yes it is. I disconected the coil to avoid a maximum of interf?rences. By the way my buzzer ring with or whithout coil when audio treshold is superior to -1.3V.

Are you sure you have the connections correct on the coil connector?

[Albdelafar]

Yes George I found my first coin with this minipulse !! But because of this audio threshold i suppose, depth is not as i can expect.

[Albdelafar]

I did somme measurements, without sound, with sound and with audio treshold set to 0V.
Looking on 2N3904 B



and looking on NE555 out :




With that I suppose my issue is lockated between TP1 and NE555. Can anyone confirm this ?

[Ssqqar12]

Hello friends
I want the necessary and final files with all modifications to make this device with many thanks

[surfdetector]

Hello friends
I want the necessary and final files with all modifications to make this device with many thanks

All of the information is here:
https://www.geotech1.com/forums/show...PP-Beach-REV-E

[Ssqqar12]

Thanks

[surfdetector]

Thanks

I did a series of build videos for this project. You can find them here:
https://youtube.com/playlist?list=PL...x32pI5m-di2GTf