IDX-PRO+VDI

[scrungy_doolittle]

are you going to make the source available? Surely would be nice.

I'd like to port it to a different chip than the PIC16 family, as well as add a realtime counter. When going out during your lunch hour at work, I'd like to be able to set a time into the counter so when it counts down to 0, you know it is time to pack it in.....
.....

[holyuser]

Аs a result is excellent. What detector is connected?

Selfmade IDX-PRO.

[Toros]

Аs a result is excellent. What detector is connected?

[holyuser]

The next version of my VDI project:

[roderico]

firmware files

To adjust the VDI do the following:

1. Adjust the contrast trimpot to see the characters in the LCD
2. Find the "ADC offset" or virtual ground for your PCB (e.g. mine is 2.49V):
   1. Select "ADC offset" from "Display options"
   2. Wait until the readings stabilize having the coil away from any metal and RF
   3. Press ENTER/NEXT button an enter this value in the "ADC offset" menu
   4. Save the changes
   
   
3. Find the lowest trigger level: the lower the higher sensitivity
4. Adjust the RT2 to have similar VDI numbers: wave a small foil above the coil and adjust the trimmer until it reads ~0 (within +-2 degrees)
5. Optionally adjust the battery voltmeter displayed at the top right of the LCD: with a multimeter measure your battery voltage and increase/decrease the voltage in the config menu until they match. This is necessary to take into account R1 and R2 values, similarly with the different components for the ADC offset.

Here there are some pictures and the firmware files for the PIC16F88 and PIC16F690:

[roderico]

new VDI firmware

I would like to add a contribution to the idx-pro with a new VDI firmware. This is not for replacing holyuser's firmware which works very well but to have an alternative firmware for testing. I programmed it myself from scratch in C and it works with the fisrt PCB layout using the MPC602 op-amp (the TL072 probably won't work well).

It does the following: first it waits for a trigger signal: x and/or y above a given threshold (trigger level). Once there is a trigger, e.g. the search coil is near to a metal it takes measurements of (x,y) for ~400ms and selects the maximum x with its corresponding y value (thus x is always greater than zero and similar for the same target), transforms (x,y) to polar coordinates (rho,phi) and displays the result until there is a new trigger.

With this simple approach, I was able to go above 70% using a Don Bowers' coil and with small power consumption (~2.6 mA without back-light). This is similar or better than the reports for the arduino, but without the need of an extra battery pack which makes the arduino not a very good option for this.

You can choose to display the rho coordinate (I called it STR from strength), the VDI name and/or the (x,y) coordinates e.g. for debugging. I also add an option to exclude the 3rd quadrant in the VDI (i.e. x and y both negative) to avoid a sign inversion that occurs when selecting the maximum x value (-90,180). But you can use the default, i.e. from -180 to 180.

The strength of the signal (STR) is related to the depth/size of the target, i.e. small and deep targets have small STR values, and big and shallow targets have large STR values. Although the VDI values depend on the alloy, size and thickness of the target I found these intervals with a Bowers' coil:

ferrous metal VDI < -2
foil -2 <= VDI < 3 (calibration)
nickel 9 <= VDI < 20
cooper 46 <= VDI < 58
aluminum 60 <= VDI < 80
silver 80 <= VDI < 110

Maybe someone would like to test it with different metals, coils and find a more generic ranges and/or a correlation with the strength to improve the identification...

[holyuser]

VDI calculates as Arctangent (Y/X), where X,Y are voltage levels measured in corresponding channels.

[jeoo888]

How to calculate the number of VDIs.

How to calculate the number of VDIs.
How to Calculate VDI.

[holyuser]

pickit2 can program this pic?

of course, quite easily

[aroma]

Hi, i have pic16f88 i/p i couldn't programmed by allpicprog and this JDM

https://www.youtube.com/watch?v=8qznzP6M2ys

it detect my pic sometimes but i cant burn it, any solution..

pickit2 can program this pic?

[lamoiz]

Good evening, I ask for your help.
On a pcb silverdog, which I just realized.
Has the power on, it emits a long and continuous sound ... coil plugged or not .... I do not know how to find the breakdown ... thank you for your help ..

[CDI]

OK I understand, but I do not think you can have 8-9V~ on TX.
Measuring with coil and you'll have a surprise.
Regards

Ofcourse with coil should be about 5 volt's.
I'm just measured on this way for pcb testing. If i dont get 8 volt's without coil, something is wrong, right?
I don't see any problem by testing pcb on this method.
Regards

[gaby_sult]

Easy, my voltage regulator is lm7809 which provide 9v.
I measured 9v on tx without coil.
Regards

OK I understand, but I do not think you can have 8-9V~ on TX.
Measuring with coil and you'll have a surprise.
Regards

[der_fisherman]

Data sheet LM3808 regulator chip....

You may find this nteresting reading:-

https://www.fairchildsemi.com/products/power-management/voltage-regulators/positive-voltage-linear-regulators/LM7808.html

Regards
Andy

[CDI]

With respect ...
Can you help me please with an explanation?
I use LM7808 and TX voltage is 5V~, how can get 8-9V~ in TX?
Regards

Easy, my voltage regulator is lm7809 which provide 9v.
I measured 9v on tx without coil.
Regards