PICKINI V4 - an easy to build, self adjusting PI detector

[BC547]

Are you saying that the pulse width will influence detection of small gold ?
Or do you ,mean the voltage sample delay that is adjustable in a classic voltage sampling PI.
The Pickini detector is a so called temporal sampling detector, it measures the pulse width of the flyback pulse.
Did you try it already on small gold?
I think the most important thing in that case is to have a really fast coil ( low capacitance)

[Joo]

Thanks F117,
I am asking this because I want to be able to detect gold that is smaller than the standard capabilities of this tool. Is it possible to make changes to the program for that?
Although we know that later detection distance will definitely decrease.

[BC547]

During the time that the Irf740 is conducting, the current through the coil is increasing. If you decrease the pulse width, the max current reached will be less than at the end of a wider pulse. The overall battery supply current will also decrease. So will your detection depth.

[Joo]

Hi Bernard...
What happened if Pulse Width changed from 100 uS to 50 uS ?

[6666]

Which is the easiest way to program the pic chip? I have Mplab but not sure how to use it.

Its very easy to do if you bought a ICSP for your chip if you didnt then you will have to use something else like solder-less breadboard, only needs 5 wires

I put all the instructions on a thread here somewhere long time ago, but this is roughly the process
I use MPLAB 8.76, its old but does all the chips I play with
plug in chip to ICSP,
open program
select chip
(sometimes the program will talk to pickit to update drivers if you change chips)
select programer
open programmer options and click power chip from pickit
File, import hex
You may get a bunch of warnings about make sure you have the right chip for 5 volts programming during the process
burn chip

[MartyJ1963]

Thanks Waltr,,,appreciate it,,,,I found a few tutorials to be going on with,,,great to learn new stuff,,lol. Thanks. Marty

[waltr]

Which is the easiest way to program the pic chip? I have Mplab but not sure how to use it. Thanks. Marty

Either MPLAB or the PICKit utility.

With both you load the hex file and go to programming mode.

Lots of instructions and tutorials on the web to do this.

[MartyJ1963]

Thanks Bernte one,,,,,much appreciated. Which is the easiest way to program the pic chip? I have Mplab but not sure how to use it. Thanks. Marty

[bernte_one]

Hi Marty,

sure you can use it for Inland treasure hunting.

[MartyJ1963]

Hi all,,,,I've been after making the Pickini for quite awhile now and I've finally put the board together,,just waiting on my Pickit 3 to arrive to program the chip. It's probably a silly question but can the Pickini be used for 'Inland ' detecting as well as beach hunting? I live quite away from any beach and don't drive,,,Thanks in advance. Marty

[6666]

I was too incapacitated from surgery earlier this year to respond to your question, so apologies for the delay.

I'm finally starting to think about metal detecting again.

The coil housing is made from two ceiling fan medallions that can be purchased from Home Depot or Lowes (in the U.S.)

I used some styrene adhesive to glue the two halves together. I have used this method for many coils and it works great, plus you can center the housing over the find and then mark it through the center hole.

Best,

Dan

Ok thanks, hope you get better, its horrible when your crook

[morganton]

Hi just wondering what you made your coil housing from ?

I was too incapacitated from surgery earlier this year to respond to your question, so apologies for the delay.

I'm finally starting to think about metal detecting again.

The coil housing is made from two ceiling fan medallions that can be purchased from Home Depot or Lowes (in the U.S.)

I used some styrene adhesive to glue the two halves together. I have used this method for many coils and it works great, plus you can center the housing over the find and then mark it through the center hole.

Best,

Dan

[BC547]

Some people asked me by email if it is possible to manually set the comparator slicing level that determines the flyback pulse width measurement.
This hack overrules the automated slicing level set up by a 10bit PWM output.
Normally, the automated adjustment will first set up the DC level of the flyback pulse and then set the slicing level to 0.5 V below the DC level after the flyback pulse.
This results in a very sensitive setting that works fine in places without any EMI distortion.
When you really want to degrade the performance of this detector because some EMI noise source is nearby - especially in-house ( but the use case for in-house appliance of this detector was never considered in the design phase), you can do so, by overruling the automated PWM generated DC level to the comparator pin.
This use case is one of the reasons why the DC level was brought outside the PIC.


The DC level for the comparator slicing level is generated by PWM output pin 2.
Then it is fed into the comparator input via R19 - R20 and C13.
The RC filter R20/C13 can remain, but R19 is just a bridge resistor: cut/remove R19 = 10 ohms and connect R20/C13 to the wiper of a 4K7 potmeter between 5V and Gnd.


When the DC level is turned outside the 1.5 - 4 V range of the analog flyback pulse, the coil error sound will be heard.
A limited realistic range would be 2 to 4.5 V.


But again: this detector was intended for the beach, not inside an EMI infested house.




Have fun,
- Bernard

[6666]

I went to the park today with my Pickini 4 and spent a short time detecting and digging. My wife made a video of my first find:

https://youtu.be/OvFEMMV0HE4

Here is a photo of the loot I located in about 30 minutes:

[ATTACH]39053[/ATTACH]

Nothing very exciting in my finds but I'm very happy with how the detector works and the pinpoint feature is especially helpful.

I'm hoping to make it to a more exciting location in the near future.

Hi just wondering what you made your coil housing from ?

[Arionas]

http://users.telenet.be/willaert/MD/...ini_16F616.hex

Right click -> save as "Pickini_16F616.hex"

Remember that this is the very first version of Pickini.
You may want to change to the Pickini v4 with 16F1824 PIC ( embedded oscillator, no need for a crystal + higher resolution: 32 MHz instead of 20 MHz)