Arduino based VDI!

[Waikiki_Sweep]

Different sounds for different targets.. Please!!!!!!!

Thank you for the great !!!! OPEN SOURCE !!!! project.

Sound, sound, sound!!! How about to convert VDI numbers into some sound sequences and listen to the music instead of STOPPING and STARING on LCD 1000 times in shiny summer day like other Whites users.
After years of using Garret ACE 250 I can say that I am looking on LCD only to change settings because it makes different sounds for different targets. So I never stop for trash target that saving 50% of my time.

[golfnut]

Launchpad MSP430

Keep a look out for the Texas Instruments Launchpad dev board.

You get a pcb, headers, 2 micros, USB lead for sub $4

ics are generally 10bit atod. some 12bit


Download the IAR dev suite for free (code limited)


I have one and I have done the flash a led program - need to get AtoDs going, and LCD display. Im going to use a nokia phone lcd as 3V to go with the micro.

Maybe never get it all going but fun trying.

S

[dfbowers]

I have not gone down this path yet
but found a good starter page, the info on software setup is near the bottom of the page.

http://www.hacktronics.com/Tutorials/arduino-flashing-led.html

Don is this the same as yours?, for $20 I will get one , onlooking around the net they seem to be changing the PCB and the chip, looks like R3 is latest.

http://www.ebay.com.au/itm/Arduino-2011-UNO-Mega328-ATMEGA328P-Free-USB-Cable-00906-/270980160244?pt=LH_DefaultDomain_15&hash=item3f17ad1af4

"The latest board continues to be based on the ATMega328, with the major change being the replacement of the FTDI chip in favor of an ATmega8U2."

That looks like the one I bought - the ATMega328 UNO from Radio Shack.

Don

[patentas]

arduino

hello can you tell me please which of these is like yours?

http://www.ebay.com/itm/EKitsZone-UNO-ATMEGA328-ATMEGA8U2-Compatible-with-Arduino-UNO-/290656044777?pt=LH_DefaultDomain_0&hash=item43ac7346e9

http://www.ebay.com/itm/New-UNO-ATMEGA-328-ATmega-8U2-For-ARDUINOs-IDE-/261050075448?pt=LH_DefaultDomain_0&hash=item3cc7cc0938

http://www.ebay.com/sch/i.html?_nkw=Arduino+2011+UNO+Mega328+ATMEGA328P+&_sacat=0&_odkw=Arduino+2011+UNO+Mega328+ATMEGA328P+Free+USB+Cable+00906&_osacat=0

[golfnut]

Quality.


I must commend your spirit taking this on.. I wrote C commercially for a year and now it all looks like jibberish - its alarming how I forget stuff.



However - there is a an entry in the first line of the code which says..

#include <LiquidCrystal.h>

This is a separate file used around the build/compile time - it must be available to your build system or it would not compile! This is the file that is referenced in your build but I cant see its content, thats all. It probably helps the lcd to run.

Comment it out and see if the build and the product works without out it and we can all remove it too!

That would be mega helpful.


With hardware platforms a cheap one is the Ti Launchpad. UK price £4 USA $3.85

you get a small board, 2 msp 430 DIL Ics, a USB lead, and there is an IDE fron IAR free.


Steve

[6666]

I have not gone down this path yet
but found a good starter page, the info on software setup is near the bottom of the page.

http://www.hacktronics.com/Tutorials/arduino-flashing-led.html

Don is this the same as yours?, for $20 I will get one , onlooking around the net they seem to be changing the PCB and the chip, looks like R3 is latest.

http://www.ebay.com.au/itm/Arduino-2011-UNO-Mega328-ATMEGA328P-Free-USB-Cable-00906-/270980160244?pt=LH_DefaultDomain_15&hash=item3f17ad1af4

"The latest board continues to be based on the ATMega328, with the major change being the replacement of the FTDI chip in favor of an ATmega8U2."

[dfbowers]

pic

Exactly!

As far as floating point numbers go, I'm not much of a whiz when it comes to programming. I hacked around until I figured out what worked and what did not. While reading about "C" programming and floating point numbers some people pointed out that you can get some really strange results when doing math functions with floating point numbers. I think I just used integers where possible before dividing, etc.

If you monitor your channels on a scope and plot on on the X axis and one on the Y axis, the vector created by the combination of the two will advance somewhere between 0 and 90 degrees, for non ferrous items. During that time, I found that I can generally sample the vector around 95 times (with the Arduino UNO) before I begin to get funky results, possibly because things settle down or swing slightly negative.
Up to about 85 samples, things become increasingly accurate.. to the point where U.S. coins will give a VDI reading with an accuracy of + or - 1!! I attempted to put as many comments as possible in the code to explain what is going on. Feel free to change anything you want.

Anyway, here is a later rev of the code I am running on the Arduino, if that is what you are using, you can cut and paste it right into the compiler. I'm not "including" any .h files.
Depending on what LCD display you might use, things may be wired differently, but I borrowed from this site for mine:

http://www.hacktronics.com/Tutorials/arduino-character-lcd-tutorial.html

Don

[golfnut]

add pic

pic

[golfnut]

Don I was curious how you got around the ...

" Problems I ran into were determining how long to sample each channel and inconsistent calculations using floating point numbers. "

thats all. Ive struggled with 2byte math on a picaxe before!


Is this in C code ?

Can you post the header file .h content please. !



You mention..
You CAN translate that into an angle using the ARCTAN function and I think that's what others are doing

Yes I also think Tan-1 is what is used.

I THINK most Rx have quadrature L.O. so the Rx outputs are in quadrature this gets the genuine phase angle x degrees = Tan-1 (b/a) to give the phase of target.

Targets like pure Silver have a response way over to RHS so you get a long a vector and a relatively short b vector


^ . ->
. b .
. . )
. . x degrees )
..........................................)....... ........>
a

You see here that alloys worth digging always have a shorter b vector to boost resolution/accuracy you may scale up the b vector (maybe not necassary)?

Steve

[dfbowers]

Hi Don. Neat work right there.

A question or two for you.



With the detector you hooked into -

1) what is the phase difference between the 2 Rx channels you used (GB and disc) - are they in Quadrature?

2)How did you get aroun the floating point mare?

Steve

Hi Steve,

I'm using the IDX Kit from Andy (Silverdog). I experimented a bit with the TGSL and the channels seem much too noisy.

There are multiple ways that you can tie the Arduino into the IDX circuit, but mine is connected to pins 3 and 5 of U4. The only drawback is that the VDI numbers will change when adjusting the DISC. I just set my DISC and leave it anyway..

You are not measuring any phase directly, but the DISC and GB channels will have amplitude and timing differences. By plotting them on a graph with X & Y components, you can create a phase relationship.. all to easy to see if you plot X against Y on your scope :

http://www.youtube.com/watch?v=m9DuMekVwic

Then, just set a trigger and measure the slope of the line that you see on the scope. You CAN translate that into an angle using the ARCTAN function and I think that's what others are doing. I'm still having trouble getting the ARCTAN to work with the Arduino. I think I might have to download another math library.

Can you ask your question again about floating point?

Don

[golfnut]

Hi Don. Neat work right there.

A question or two for you.



With the detector you hooked into -

1) what is the phase difference between the 2 Rx channels you used (GB and disc) - are they in Quadrature?

2)How did you get aroun the floating point mare?

Steve

[fixstuff]

I love this. Has anyone done a full metal detector with the Arduino?

[dfbowers]

Great work Don. Congratulations.

I cannot find nothing about power consumption?

Probably depends on how many pins you are driving.

Looks like recommended power range is 7 - 12V from an external souce. I'll have to check mine out before thinking about hooking it directly to a detectors regulator.

[WM6]

Great work Don. Congratulations.

I cannot find nothing about power consumption?

[hdphilip]

nice job Don,

your code even compiles on Mpide 0023 for my Chipkit uno 32 !!!

Philip