Discriminator probe pointer

[keith777]

Bought the pointer on the 23 May delivered today to the UK from Bulgaria all safe and sound. Thought it was kit i had to build but built already which is great. Great bit of kit, works great, now to put a casing around it to. I was wondering if the casing of an old garrett type pinpointer, may be a Chinese cheap knock off would be suitable, anyone know the internal sizes. The board diameter of the new hobby pin pointer is 27mm wide and 64mm long plus the battery to fit behind.

Hi Topfmine.
i got my Discriminator Pinpointer PCB in the post today. can i ask you. does yours allow you to switch yours off.? the one i received. if you press the button it makes the beep/bloop noise but it does not mater how many times you press it, it is still switched on. if you leave it to stand for a few minutes it gives you a beeping warning that it is left on and not in use. also sometimes the blue light just stays on plus bleeping for no reason till you press the button to stop it. i am pretty sure it is not meant to be doing this. just thought i would ask you about this with you buying the same thing.

thanks in advance...........

[Topfmine]

Yes mine does that must be some way to switch off, maybe press the switch twice, not sure, may have to look at the video. It may pay to add a switch on the wire leading to the battery. i am going to make a casing for it out of a solid lump of plastic on the lathe rather than rob an old pin pointer.

[keith777]

Yes mine does that must be some way to switch off, maybe press the switch twice, not sure, may have to look at the video. It may pay to add a switch on the wire leading to the battery. i am going to make a casing for it out of a solid lump of plastic on the lathe rather than rob an old pin pointer.

Topfmine thanks for the reply.
what about the random flashing and bleeping. does yours do that as well. just making sure in-case mine is faulty in that way.

[Topfmine]

I found this but if you are in an area surrounded by metal draws and cabinets or near large metal objects it is erratic but away on its own its ok. i found when i was testing it on my bed it reacted to the springs in the matteress.

[keith777]

as soon as i plug the battery in to mine, it just starts beeping like mad with the blue light flash as well, until you press the button. well that was a waste of $29.00

[Andi68]

I think a pin pointer with discriminator is superfluous.


I will try the Teemo circuit - small with few components

[Skippy]

"I think a pinpointer with discriminator is superfluous"
I tend to agree, if you are just using it as a pinpointer. However, if you were intending to use it as a stand-alone detector, the discrimination is time-saving.

I am ( slowly ) experimenting with this simple Polish discriminating detector circuit:
https://www.geotech1.com/forums/show...387-PINPOINTER
I'm working on the search coil at the moment.

[waltr]

I think a pin pointer with discriminator is superfluous.


I will try the Teemo circuit - small with few components

If you use a PI detector then disc in the pin pointer is nice since the PI has no disc.

My pin pointer is based on Teemo's design and works well.
When it gets the wobbly sound for non-ferrous I get excited.

[Andi68]

Ok Waltr, I agree with you.
I have considered whether the principle of Teemo also works with a conventional PI circuit?

[waltr]

Ok Waltr, I agree with you.
I have considered whether the principle of Teemo also works with a conventional PI circuit?

I have started experiments to use those principles with a PIC32MX processor and a PI front end, MOSFET switch & pre-amp plus a MOSFET to switch in a resonant cap. Got off on other projects before getting this to work.
In theory this could be a way to get ferrous/non-ferrous disc from a PI.

Teemo's circuit is interesting and worth prototyping to play with. The key is the LC resonance and how the frequency and decay changes with different targets.

[Andi68]

I do an experiment on occasion, connect a capacitor in parallel to the coil and see what happens

[keith777]

i sent a message to the sell about the problem with the pinpoint. i got a reply back today.....

[dbanner]

[Topfmine]

I sent New hobby a email and said i had the same problem as Keith777. They replied and said they will send out a 60mm round coil which works much better. Today i received the coil with in a week from Bulgaria all the way to the UK. in my opinion a good service no problems, fully recommended for anyone dealing with New Hobby, will buy again good little device, now to build a casing for it.

[WM6]

Past year I use this "pinpointer" board, with 60mm coil, as "not conspicuous" small beach/surf detector.

Works well. Buy another one. Good job from New Hobby.