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

[F117]

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]

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.

[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

[F117]

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

https://youtu.be/2i46AAajaIM

[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

[F117]

SOFTWARE UPDATE

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

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

[F117]

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

[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.

[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

[F117]

The difference in calibration is that the starting point for the DC offset is now kept in EEPROM and started from there.
Previously, it was a successive approximation, starting from the middle value.
I didn't notice any difference with the prototypes I updated, but you have a point that there may be a difference of maybe 1 calibration step up/down.
I will check it as soon as I have time and upload both versions to the website.

Pin7 is just an unused output pin. No need to do anything special with it. If you haven't connected anything to it, that is fine.

Thanks for your feedback,
- Bernard

[F117]

I reverted the change to start the calibration from the EEPROM value.

The stable detection output at pin 7 is still in place.
Files updated here:


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

[ripsdevala]

Thanks for the update Bernard sir, will test it.
Btw, i have many salvaged irf630,640,840 can i use this for irf740?

[F117]

I think you can safely replace the IRF740 with IRF840:
IRF740 : VDS = 400V and IRF840 : VDS = 500V.
IRF640: VDS = 200V only, so I would not use these.

[ripsdevala]

irf840 is working ok, new firmware= fast auto tune

[ripsdevala]

REPORT
When i use coil 400uh and 350uh, thickness about 0.4 - 0.5mm insulated plastic wire I found lying in back of my house, it will totally eliminate emi interferences, now i can use it with full sensitivity in the house.