Realy working Proscan schematic.

[12V]

I built it, not working a i mess it one day..... and working

[12V]

I not find NAND schmitt-trigger 4093, replaced it russian **** K561LA7 (4011), this working very well, i not have oscilloscop, can`t see how clear is timing pulses.

[Carlos]

proscan=gerber

hi 12v, why not built this circuit whith my modifications? https://www.geotech1.com/thuntings/s...ghlight=tl431m its very sensitive a stable

Carlos

[12V]

Hi Carlos

I see this topic first time, this is interesting modification.
How deep find 2,5cm diameter coin, so that detector give clear-screaming signal?

[sonar]

http://www.detektory.wz.cz/schemaPI.htm

Here You have all about Proscan PI detector. I make this one and work nice. 2,5 cm coin? On 30cm coil - that was 22-25cm

Check BD911 position on orginal PCB. Take a look at Sandbanks PI...

but gold detection is 0%