Android Phone Based Metal Detector - FCMD

[moodz]

Hi Paul,

your final ENOB of 21 bits on a fast 16-bit ADC is quite good. It is even better than most slow 24-bit ADC's can arrive.
Well, I don't get the same level of performance on my 192 kHz/24 bit sound card. I'm limitted to relative low frequency responses, which limits the total detector sensitivity.

I'm really impressed of your KISS and cheap project. Well done!

Thanks Aziz ...

You dont have to be limited .. these boards are very cheap and all tools are free / open source.

[Marchel]

I developed a metal detector development board for these STM32 boards. Here are the latest documents, I have the latest board made at home but I haven't had time to test it yet so I don't know if there are any bugs on the board.

[ivconic]

Here is an engineering presentation on a new detector to management.

https://www.youtube.com/shorts/L2-krroaLqQ

I am developing a new business strategy that will work in the spirit: WeDontAct-WeStayPut!

[Aziz]

Here is an engineering presentation on a new detector to management.

https://www.youtube.com/shorts/L2-krroaLqQ

This is great magic.

[moodz]

I developed a metal detector development board for these STM32 boards. Here are the latest documents, I have the latest board made at home but I haven't had time to test it yet so I don't know if there are any bugs on the board.

Good work...what is your transmit scheme.

[Marchel]

Good work...what is your transmit scheme.

The RX part is based on Minelab coils and the TX circuit is based on the XP Deus 2.

[moodz]

The good news .. the ground balance test in the field worked better than expected.
Easily balanced a range of goldfield grounds except beach ( to do ).

The bad news ... trying to video one phone (running the detector app) with another phone and holding the detector on a hot day with severe shading and reflections just did not work.

...So I have changed the app so it can do all the video work.

It records the detector app screen in real time and overlays the front or back cam on the screen.
1 tap toggles the video to full size vs PIP ( picture in picture ).
2 taps toggles the video back / front cam.
The PIP may be dragged to any position on the screen.
The detector app controls are fully functional and will be captured if you are recording.
You can stop or start recording obviously and sound may be captured or muted.
Video is captured as MP4
The default is PIP ( recording off ).

Below is a screen shot from a short video shot just now in the lab ... .... might add timestamp and GPS coordinates ( or not ).

This should make detector videos in the field really easy ... I hope.

[Marchel]

I see that you are using the HC-05 Bluetooth module to transfer data to your phone. I think it would be worth trying to use the nrf24l01 for data transfer because it should also be able to communicate with the phone via BLE and its power consumption is lower, I think.

https://www.youtube.com/watch?v=2ZlZVE3XjOw

[moodz]

I see that you are using the HC-05 Bluetooth module to transfer data to your phone. I think it would be worth trying to use the nrf24l01 for data transfer because it should also be able to communicate with the phone via BLE and its power consumption is lower, I think.

https://www.youtube.com/watch?v=2ZlZVE3XjOw

That is a possibility...but also looking at simultaneous audio and data over BT using BT401 or similar.

[JoyJo]

But in the very idea of using Bluetooth, aren't you confused by the delay in sound transmission? At the moment I know only 1 fairly good chip with support for fast codecs and at a reasonable price: csr8670. By the way, it is installed on equinox. However, there is another chtp CC8530 on the equinox. They work on one antenna and switch with a high-frequency radio switch. But that's not the point. And the essence is the delay of sound transmission that Bluetooth has. Nrf24l01 has a very low delay even in comparison with csr8670.

[moodz]

The HC05 is just a stop gap measure to send some data to the app for testing ... the software is the priority. Wired headphones are fine for now.

[moodz]

Here is the FCMD app video .... the video was made by the app itself ( no editing ).
This makes detector videos super easy ..

[syavash]

Here is the FCMD app video .... the video was made by the app itself ( no editing ).
This makes detector videos super easy ..

hi mr moodz.
thank you for your nice & exciting work.
congulation.
i'd like to make it, but unfortunately i cant find your app.
would you please out it here ???????
please help me.
so so thanks.
best regards

[moodz]

hi mr moodz.
thank you for your nice & exciting work.
congulation.
i'd like to make it, but unfortunately i cant find your app.
would you please out it here ???????
please help me.
so so thanks.
best regards

... thankyou for your comments .. this is still a work in progress.
I am just reporting where I am up to in the project.
It is not ready for release yet.

moodz

[Aziz]

Hi Paul,

maybe I should buy a few STM32H743VIT6 boards to be able to use your ultimate detector soon.
The STM32 boards are really quite interesting.
Cheers