Can pinpointer detecting thin chain?

[detectoman]

hello nupi .. ufssts, wwwhhw.. then you is shure, real ? jajjaj -- may be you need any good vacations whit any fresh sea airs

[detectoman]

thanks very much brodhy thomas,

[Nupi]

Hey Nupi, in the drawn picture of the coil in post #410, you have L2 as 330uH, but in the text you have L1 as 330uH ????
your picture did not attach to this quote.

Thanks, You are absolutely right.

See my new avatar!

This is the real, real, real, real, real one.??????????

[Beenthereuk]

I've built similar things for fun in the past. Some ideas to avoid the constant whine produced by such a circuit (some of which I have tested):

A simpler (single coil - no tap) oscillator running at around 200 kHz (similar to this):


Program a PIC to capture the rising edge time from the output from the counter and produce an output when this signal drops in frequency.
It can be coded to capture the no-metal frequency of the signal by pushing a button near ground but away from metal and this value is then used for the comparison when detecting.
The colpitts oscillator is quite stable in practice but adding a FET buffer to it before taking the signal to the counter helps improve stability.

Alternatively, build a 4th order (or better) analogue filter designed to pass only frequencies below the no-metal frequency. Two Sallen-Key op-amp filters in cascade should do the job.

http://sim.okawa-denshi.jp/en/OPseikiLowkeisan.htm

[Thomas]

can i put the mc14024

Yes

[6666]

ToddB66 said to me, that he found the data from the pinpointer confused.

***He has absolutely right, I've messedup.***

I often (I mean to frequently) made mistakes.


That's why I post all the data of the PP together.


I hope this time without error.

Hey Nupi, in the drawn picture of the coil in post #410, you have L2 as 330uH, but in the text you have L1 as 330uH ????
your picture did not attach to this quote.

[detectoman]

semms these cd4024 is obsolete in my country

[detectoman]

hello guys i like make too this pinpointer, a question by yours my problem is, because in my city isnt avaliable cd4024 ¿can i put the mc14024
ou attention thanks very much, excusme my bad english
hola muchacho yo veo a hacer tambien este p.p, una pregunta a ustedes, mi problema es porque en mi ciudad no es conseguible el cd4024, ¿ puedo yo poner el mc14024? por su atencion muchas gracias

[ToddB66]

Hi ToddB66,
I've made a lot of PP. Most are sold. I can take a picture of mine "workhorse" Nupi PP MK2. It is slightly larger than the normal NUPI PP but he has more depth than the normal NUPI PP. 16.5 cm with one euro. I still have empty housing and parts of NUPI PP, I can take a picture of it if you want, I'll see when I have time for

Nupi,

Re the "normal" NUPI PP, please send E-mail to me at [email protected] with picture, price including S&H and key features for (1) NUPI PP.

Thanks,

ToddB66

[Nupi]

nupi,

Have you built a working model of the "PINPOINTER - NUPI - 2014 - Final" ? Would like to see a picture of the completed PP installed in the housing if possible.

Thanks,
ToddB66

Hi ToddB66,
I've made a lot of PP. Most are sold. I can take a picture of mine "workhorse" Nupi PP MK2. It is slightly larger than the normal NUPI PP but he has more depth than the normal NUPI PP. 16.5 cm with one euro. I still have empty housing and parts of NUPI PP, I can take a picture of it if you want, I'll see when I have time for

[ToddB66]

PINPOINTER - NUPI - 2014 - Final

nupi,

Have you built a working model of the "PINPOINTER - NUPI - 2014 - Final" ? Would like to see a picture of the completed PP installed in the housing if possible.

Thanks,
ToddB66

[Nupi]

OK, done.

[Davor]

Nice catch, let the upper one at pin 3 be R18. Value is OK.

[Nupi]

Thanks for the info, Can you look at two same-numbered resistors? Number 10 is 2x. one of the drain and the other U2 pin 3. Could you give me another number?

[Davor]

Good luck
You asked about C9, and maybe it'll require some extra care. There is a dependence between C7 and C9 regarding a timer period and reaching stabilised conditions, so perhaps C7 may need increasing. I designed these to reach a solution in ~1s.
I expect TR2 to be sufficient for reaching a solution. Expected behaviour is: "click!beep... beep-beep-beeeep (ready) ....." or "click!beep... beep-beep-beep-beep-beeeep (ready) ....." and the number of beeps in a row is set by TR2.