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

[morganton]

Hi Bernard,

First, thanks for upgrading the firmware. I appreciate your continuing efforts to improve the detector.

I tried out your revision with a new PIC. I did not attach an LED to pin 7 since I'm already using an LED as a power indicator and don't really need a detection indicator.

It seems that with my build, the detector is not as stable with the new firmware. It randomly and often beeps after the initialization, although the detection depth is about the same as with the original firmware. I reinstalled my original PIC with your first version and there is no instability at all.

I'm wondering (to use the new firmware) if I should do something with pin 7 of the PIC now that it is synced to the detection, although unconnected on my board?

Also, would it be possible to upload the original firmware (and maybe keep all of your firmware revisions on your website)? I have the original burned on a separate PIC, but I'd like to have a copy of the source code.

Best,

Dan

[chevesne]

Nice upgrade!
I'm glad to know that the tempo of 1hertz is random after the initialization, I thought that my circuit had a problem.

[BC547]

A video to illustrate the faster startup + static detection output ( LED )

I added a video on youtube to illustrate the faster startup by reusing the last calibration value stored in EEPROM + the static detection indicator LED.
The video was made on the dining table and is the quality is not so good due to bad lighting / camera / unexperienced operator ...



Scenario:
1. Overview of the test setup: PICKINI V4 PCB connected to sensitivity potmeter, small loudspeaker at the headphone connection, 12V power supply and basic 8" / 20 cm test coil.
2. I switch on the power supply - followed by welcome sound and 1 Hz tick
3. Calibration complete after 10 seconds ( compared to 20 s without the EEPROM storage )
4. Detection of a screwdriver to demonstrate the functionality of the LED connected to pin 7 of the controller ( with 1K in series ). Here I used a hi-bright white LED. You may connect a vibrator / piezo beeper / ...

Disclaimer: this video is not intended to show the detection capabilities ( depth / sensitivity / .. ) of the detector. It was made in the worst possible conditions: inside the house with a lot of EMI around. I had to turn down the sensitivity to almost minimum. The right way to do this is to go outside the house and switch it on there. On the beach I can crank up the sensitivity to almost maximum.

PS: having all the parts at hand, it took me a little over 1 hour to stuff the board.

Enjoy,
- Bernard

[BC547]

SOFTWARE UPDATE

I just updated the HEX file and the C source here:

http://users.telenet.be/willaert/MD/pickini/pickini_en/V4/software.html

2 new functionalities - backwards compatible:

• When the detector starts, an internal calibration is done to determine the slicing level for the flyback pulse. This may take between 10-20 seconds. The value is now stored into the internal EEPROM of the controller. Starting from this final value of the previous calibration, the startup time is reduced to less than 10 seconds. However, when the battery voltage has dropped significantly between 2 startups, the calibration time may still be longer.
• Pin 7 of the controller was free. It is now a digital detection indication: HIGH = detection. It may be connected to the anode of an LED via a 1K resistor - or to a beeper or vibrator ( via a series resistor or extra transistor ). There is no extra pad on the PCB for this pin, so you need to solder it directly to the controller pin.

CAUTION when attaching devices to the controller pins ( audio pin11 and detection pin7): DO NOT LOWER THE SERIES RESISTOR BELOW 1K. When drawing too much current from the pin directly, this may lead to oscillating / unstable detection behaviour.

Enjoy,
- Bernard

[ripsdevala]

My opinion is that underwater, you should find more valuable objects (rings, watches, etc..)
Cause you loose much more easily objects when swiming than when sleeping on the beach. That's why a simple design would be usefull
underwater. That's my opinion

Hi,
Are your wireless charger work repto? For underwater, please share the technique

[BC547]

I finally managed to upload a video from my website to youtube

https://youtu.be/2i46AAajaIM

[reptooyep]

My opinion is that underwater, you should find more valuable objects (rings, watches, etc..)
Cause you loose much more easily objects when swiming than when sleeping on the beach. That's why a simple design would be usefull
underwater. That's my opinion

[morganton]

I think every PI user would want some discrimination indication...
Unfortunately it is not possible with this simple design. On the beach, I just dig everything, of which about 1 out of 10 (optimistic estimation) is something worth keeping (unless you collect pull tabs...).
On farmland, this is even worse. I find a lot of unidentified iron blobs, which sometimes turn out to be something historical after cleaning them via electrolysis.

The positive side of this is: you get some exercise and the hunt is never boring

Yes, absolutely. I've never found anything really valuable, except for the exercise and the excitement of the hunt.

Thanks for replying.

[BC547]

do you think there is any way to modify your source code to give an indication of probable detection of coins

I think every PI user would want some discrimination indication...
Unfortunately it is not possible with this simple design. On the beach, I just dig everything, of which about 1 out of 10 (optimistic estimation) is something worth keeping (unless you collect pull tabs...).
On farmland, this is even worse. I find a lot of unidentified iron blobs, which sometimes turn out to be something historical after cleaning them via electrolysis.

The positive side of this is: you get some exercise and the hunt is never boring

[morganton]

Thank you for the kind comments.

Bernard, I hope that this doesn't seem like a silly question (I'm not an engineer), but do you think there is any way to modify your source code to give an indication of probable detection of coins? Say, for example a ding-ding as opposed to a normal ding? I'm not advocating discriminating iron, etc., just maybe a better guess as to coins.

[BC547]

@ morganton:
Thanks for the pictures !
A very nice and professional looking build

[WM6]

Good work morganton.

[morganton]

Pics of my completed Pickini

Here are some pics of my completed Pickini 4.











Pics were posted a little smaller than I anticipated. You can use Ctrl - + to enlarge them.

I think I construct my detectors similar to the way most folks do it, but here are some construction details if anyone is interested:

1. All body construction is from PVC plumbing fittings. The lower shaft is stiffened with a dowel that I sand to fit inside the 1/2" PVC shaft. All fasteners are nylon, except for the brass screws that connect the battery case.
2. The coil housing is made of two (2) 10" styrene ceiling fan medallions glued together. I like the center cut-out that makes marking a find very easy.
3. The coil bracket is made from 1/8" acrylic strips laminated together.
4. The arm support and bottom support is a 4" PVC coupler cut in half and shaped.
5. The coil cable is a 3 conductor computer power cable.
6. The hand grip is tennis racket handle wrap.
7. The detector housing is spray painted with Rust-Oleum Ultra Cover for plastic.
8. The arm support material is from a mouse pad.

As soon as it stops raining here in Norcal, i'll do a video of the detector in action.

Thanks again to Bernard and all of the contributors.

[BC547]

Or a little more obfuscated:
BEEP=(pulsediff==64) ? 1:0;

[BC547]

Typo correction:

if (pulsediff==64){
BEEP=1; //output 11=1
} else {
BEEP=0; //output 11=0
}