Simplest PI detector possible?

[tittus]

[]24323[/ATTACH]

[tittus]

here are some pics
will later by more
thank you all

[WM6]

Interesting solution.
Did you try to put water in your plastic-container-coil and detect something underwater?

[tittus]

No, the container only has the needed measures to make the coil. It was the easiest I found.

[Davor]

So did I

[Watanabe]

Titus
I'm very confused with your coil... :/ ...
you use 4 wires: black. green, yellow and orange?? How is this???
You have a youtube channel???
Can you show details of coil??


Thanks.

[tittus]

good night
are only 4 wires that I joined to make long
4 wire 12 meters, with diametro.3mm
the two together, of which: two wires 24 meters
By the end of 1 24 meters with wire .6 mm Excuse the bad English


thank you

[6666]

While looking for something else I found this, it may have been posted already but here it is again
its a video of the pirate, and looks to be a good build, and works well for a simple circuit.
I think it says he replaced the irf740 with a irf630 and got an improvement in detection distance

http://www.youtube.com/watch?v=SYR_ZlQ29Gc

[Davor]

It makes sense. IRF630 has almost half capacitances.

[migusch]

Surf

Hi, folks!
I've got a similar problem like brucester when he opened this thread: I'm looking for a very simple PI that my 10 year old nephew can build with the necessary guidance from me. I already built hammerhead and some non-PI-detectors so I think to have he skills to help my nephew to succeed this project.

We want to build a surfPI because it promises to be very simple and therefore reliable, but I recently read somewhere here on geotech that surfPI is intended for beachhunting and not very useful for inland metal detecting. Is that right? Unfortunately we don't live on the coast. The main purpose of his future metal detector will be to serve as an advanced toy to get familiar with basic metal detecting. He maybe will do some coinshooting on playgrounds or try to find some long-forgotten matchbox-cars in public sandboxes. In the beginning he will be pleased to find rusty nails in the garden and the like...
Will SurfPI do the job? What is the functional downside of surfPI compared to other PI-detectors?

Next question:
There seem to be several versions of surfPI (and some may be the same):
- surfPI
- surfPI pro
- surfmasterPI
- the "clicker"-version
- ...?

How many different official versions do exist and what is the main difference between them? Which one is most suitable for a 10yr old boy to play with?

Thank you for sharing your expertise,
migusch

[woodbob123]

My grandsons both were built surf pi's they very soon got fed up of iron nails and silver paper. Now have to build something with discrimation for them (granddaughters are happy with small spade and pin pointer) I would suggest you buy inside the metal detector and build one from there. It has the added advantage that as they ask questions I can hand them the book and say read it for yourself, (then explain to me).

[migusch]

Thank you for your reply, woodbob123!
I already own the book "inside the metal detector" and almost know it by heart. Discrimination will be one of the next steps for sure, but we don't want to skip the very first step because building metal detectors is an end in itself for people interested in electronics. And a mono-coil for a PI is way simpler to build than a well balanced IB coil. The boy recently did some initial "metal detecting" with a big magnet which he pulled through the garden on a cord, so a stable working PI-machine will be a huge step forward for him...

[WM6]

The boy recently did some initial "metal detecting" with a big magnet which he pulled through the garden on a cord, so a stable working PI-machine will be a huge step forward for him...

And you say, you need discrimination as next step? This what your boys alredy have is the best Fe discrimination possible.

[woodbob123]

Oldest at 8 years old now needs things that challenge him so the ITMD bfo has a very simple coil is a easy build and more importantly easy to understand and explain thanks to the book, If they get used to solder fumes lol early in life they will have an advantage in years to come, bfo also has advantage of shallow depth so targets are easy to dig. We also have used a large magnet near a boat lock on the Thames had great fun pulling spanners and some steel cored coins out of the water after 30 mins had a small crowd watching and helping. Great fun I never want to grow up.

[migusch]

You are right, woodbob123, the BFO and its coil are relatively easy to build but I was a little disappointed by the low depth and stability. (I thought you relate on VLF-IB when you mentioned discrimination) I built the ITMD-BFO for use as a pinpointer-probe but it didn't work as it was supposed to. Maybe I should give it a second try but we don't have to discuss that in this thread...
For now we need no discrimination at all besides what WM6 denoted: a shovel and maybe a magnet...
Thank you for your replies.

I still like to get some opinions in question of whether surfPI is capable of "inland metal detecting" and of the main differences between the different versions...