Arduino metal detector shield?

[msysta]

How about sending the delta value compared to previous sample? Then difference data should fit into smaller (1 byte or half byte size?) datatype.

Also it could be usable to do FFT on Arduino...
http://www.arduino.cc/cgi-bin/yabb2/...m=1286718155/2

[dingbatca]

"delta value compared to previous sample"

The RX-Arduino will be running two samplers, one off the TX line, and one the RX line. The delta value will compare to the current RX to TX samples. I will then pass that value up to the phone, and let it do all the cool math, graphing, and generation of the audio tone.

FFT's... Heck ya! But there is a catch. The Arduino can do it, but I am out of clock cycles! I need more power(MHz)!!!!

[dingbatca]

Coil came in today.
http://www.amazon.com/Bounty-Hunter-.../dp/B0008DBP8U

Looks like shield and pin 1 are NC. Pins 2, 3 = 10 ohms, Pins 4, 5 = 15 ohms. The whole coil is epoxied together. That will make opening (If needed) a pain, but not impossible. :-)

Still waiting on the DAC/ADC chips. They will be here Monday.

My replacement oscilloscope should be here next week (I hope).
http://www.seeedstudio.com/depot/dso...?cPath=104_108

[msysta]

I should also buy ADC, maybe you could give me a hint where to purchase. Needed resolution is 18 bits and speed 3MSPS.

[dingbatca]

I picked up all my hardware through Digikey.com

Needed resolution is 18 bits

2^18=262114

Might I ask what is driving you to need that kind of resolution?

[msysta]

To measure delicate differencies of a pulse that decays very fast and goes over 200 volts on circuit

[BillBert]

Looking to build a simple VLF/IB metal detector. I plan to use an Arduino for all the signal comparison/processing. I would like to put all the hardware on an Arduino shield. Keep the whole project open and free, hardware/code.

I am good with code logic and algorithms, but suck at designing hardware.

I need help with two circuits (Not sure on the power, or the amperage):
1) Amp circuit to take the signal generated by the Arduino (5Hz~64kHz square wave) and pump it up to 200~1000ma, for the TX coil.
2) A opamp to take the signal from the RX coil from 0.001~50mv to 0.1~5V for the analog in on the Arduino.

Lets start simple. I would like to detect the difference between open air, and the metal hood of my car at 1in away

Is this a sound idea? Am I going about this correct?

So, I am curious as to where your project stands? It is of interest to me as I have been contemplating a similar idea.

[fromfrance]

i'm curious too ! i use arduino for over project ( aerial photography)....

[Farside]

I found a place that ships globally for free:
http://s.dealextreme.com/search/arduino

I bought some Arduino nanos for $17 and they're great.

We should definately pursue this project. Imagine having an Arduino (or Netduino) based "front end" which you could "plug in" to any detector "back end" and just load the appropriate software :-)

FWIW I also got one of these:
http://www.dealextreme.com/p/vap11g-...ge-blue-100432

So I can achieve wifi communication on my Arduino project without the need for a wireless shield which is way more expensive!

[fritsjan]

Hi All,

I also want to make a metaldetector with arduino. I want to make a vehicle loop to detect a small bicycle (iron). However, the ground on which the loop will be placed is full of aluminium tubes.. Which is also detectable by metaldetector.
However, I did some testing with a cheap VLF detector and could do some nice things with discrimination.

I placed 2 aluminium tubes on the detector coil, the VU meter shot to the right (non-ferro scale). Then, while the aluminium tubes were still in place, I moved a small piece of iron over the coil -> the VU meter moved to the left (towards the ferro scale). So it is possible to detect a change even when the detector detects aluminium constantly. And since the aluminium won't move this could be my neutral state.

In the end I need my arduino to switch a led on or off when something of iron moves over the coil. So I need to get the input of the VLF frequency in the arduino and could then be able to detect any changes compared to a neutral state (which it could also automaticly detect on startup).

Since this project is similar to the one in this tread, could someone help me select the right schematics for building the metal detector part?

To put it simple I need:
- output signal to send coil (this might be done by arduino but could also be generated seperately)
- input signal from receive coil to be converted to input in arduino
- maybe some help with building a 0.5x1.0m square coil(s) surface

Thanks in advance!

[fixstuff]

Hi all,

I know this is an older thread, but did anything ever come out of this? I'm looking at the FRDM-KL25Z from Freescale and I would like to couple this to an Arduino Metal Detecting Shield if there is one out there. I want to use this with the MBED platform online compiler, but wanted to see what was out there in terms of a schematic design for a MD shield. The nice thing about this board is the online compiler and price - $12.95. It would be very easy to share this design as well, since the online source code can be made accessible to any who are interested. Might be a real quick, easy way to get hobbyists up and running with a custom metal detector. I'd love to be able to buy a PI or VLF Metal detector shield from someone like Silverdog. Any advice?

Some links for it:

http://mbed.org/handbook/mbed-FRDM-KL25Z

[mickeu]

My shield

I build it when i try to play with menu and buttons/encoder for metal detector and i get too much with wires on breadboard:

http://mickeu.wordpress.com/

next shield that i work over now will be with pulse induction md TX and RX circuit

[bernte_one]

found another one
http://magelab.ru/index.php/retsepty/4-ippulsnyj-metallodetektor-na-arduino-izobretaem-velosiped

[scrungy_doolittle]

Hello dingbatca,

Advice from Qiaozhi is o.k. but you can also look here for the schematic from the Tesoro lobo or diablo , there is a nice transmitter and receive circuit in it
Go for 18-19 kHz, but 200-1000mA (1 AMP) is a to much

Regards

Ap

https://dl.dropboxusercontent.com/u/...l_detector.ino

A guy named Mr. Crocker did this one https://github.com/dc42/arduino