Can pinpointer detecting thin chain?

[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

[detectoman]

semms these cd4024 is obsolete in my country

[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.

[Thomas]

can i put the mc14024

Yes

[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

[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.??????????

[detectoman]

thanks very much brodhy thomas,

[detectoman]

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

[Nupi]

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

Hello detectoman,---
What is certain? Nothing is certain, that's for sure. What is sure, when nothing is certain????
When nothing is sure and nothing certain, how do you know when something is certain or sure????????------- ------

Maybe you're right and I need Vacation!!!!! ------

[detectoman]

jajaj GOD GLORY!

[jwms]

looking for something just like this. what size of wire used in the loops?

[johnandles]

looking for something just like this. what size of wire used in the loops?

http://www.geotech1.com/forums/attac...2&d=1405848258

[jwms]

Thanks for the update. My bad!!!! After I posted my query, I realized there were many more pages I needed to look through. I apologize for the stupid mistake on my part. All of you may laugh. I will not know if you do or if you feel sorry for me. I am laughing so it will not bother me as long as most of you do not tell me I am stupid. (I have a great sense of the humor of my mistake. Hope it brightens every-bodies day. A good laugh, even at oneself is good medicine.) I will start on it in the next few days so may have some questions if I run into any problems. Really like the features!! Thanks for the work that was put into this!!

[Polymer]

Hello Nupi,

I am absolutely thrilled with your design and really appreciate and adore your step-by-step picture instructions!

Yes, yes, yes! I will be building a Nupi-Pinpointer

I do have a few questions though, argh:

Are the tolerances critical for R's and C's. Would it be better to use 1% resistors and 5% capacitors instead?

Could i use one piece of ferrite with 19mm diameter instead? Or perhaps asked better: how critical are the dimensionalities
of the ferrite core? I'm asking because I would like to make do with what I can get here locally.
An absolute heads-up on your construction

[Nupi]

Hello Nupi,

I am absolutely thrilled with your design and really appreciate and adore your step-by-step picture instructions!

Yes, yes, yes! I will be building a Nupi-Pinpointer

I do have a few questions though, argh:

Are the tolerances critical for R's and C's. Would it be better to use 1% resistors and 5% capacitors instead?

Could i use one piece of ferrite with 19mm diameter instead? Or perhaps asked better: how critical are the dimensionalities
of the ferrite core? I'm asking because I would like to make do with what I can get here locally.
An absolute heads-up on your construction

5% resistors can be used. The value of the capacitors are critical.
You can do some differ from the values but you need to know what you are doing.
You can use a different ferrite if you keep to the inductions.
You will need to use an induction meter.
If you can not build the same as in my example then I can unfortunately not give you support. Sorry!