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

[geoscash1]

pin 10 PIC voltage is wrong - it should be more than 0V - this is the reference voltage for the internal comparator. This is generated as PWM from pin 2 and filtered with R19 / R20 / C13 and then fed into pin 10.
Check this voltage with the scope during the initial calibration cycle.
The other pin of the comparator is pin 8/9. Measure there with the scope, this should be a negative going flyback pulse from 5V down to 2V.
The pulse to the IRF740 gate should be 100 microseconds wide.

The low tone after the calibration cycle is the COIL ERROR sound: no flyback is detected at pin 8/9 inputs of the PIC.
At first sight, I don't see anything obviously wrong on your PCB.

I assume you used the hex file as is, and not rolled your own ?

- Bernard

Hi Bernard,

yep, I used the hex as downloaded from your site.

I rechecked the voltage at pin 10 with my scope and still get no response or 0v. I tried the headphone test and can clearly hear a tone which is saying the coil is being pulsed, at least that's my understanding from other builds.

I measured pin 8/9 with scope and it definitely goes from 5 to 2v but is positive going, not negative. I used the tp on board for this test.
checking the coil with my scope leads across the coil connections gives a good signal (as shown in previous pics).

Let me try to reload the hex, recompile and write to the chip, I'll double check all the settings (mclr etc) and then go from there..

thanks for the quick replies guys, much appreciated...

[WM6]

Hi Bernard

Did you think about low consumption version of PICKINI in pin-pointer design, powered by ordinary 9V battery?

Do you have such pin-pointer PICKINI solution?

[morganton]

Geo, your PIC's pin 4 should have around 5 volts. You can check the project settings for the PIC to see if you might have "MCLR Pin Function Select" enabled (it should be disabled) and also to match F117's other recommended settings. Also, I had the "Oscillator Selection" incorrect which caused the PIC to run too slow. It should be "INTOSC oscillator: I/O function on CLKIN Pin". These incorrect settings caused mine to not work. See posts 84 and 227 above.

[BC547]

pin 10 PIC voltage is wrong - it should be more than 0V - this is the reference voltage for the internal comparator. This is generated as PWM from pin 2 and filtered with R19 / R20 / C13 and then fed into pin 10.
Check this voltage with the scope during the initial calibration cycle.
The other pin of the comparator is pin 8/9. Measure there with the scope, this should be a negative going flyback pulse from 5V down to 2V.
The pulse to the IRF740 gate should be 100 microseconds wide.

The low tone after the calibration cycle is the COIL ERROR sound: no flyback is detected at pin 8/9 inputs of the PIC.
At first sight, I don't see anything obviously wrong on your PCB.

I assume you used the hex file as is, and not rolled your own ?

- Bernard

[geoscash1]

Finished but not quite right yet

Well finally finished up my pikini, seems to have loaded hex correctly as when firing up the board it gives the initial double beep, then goes into a slow tick for about 25 seconds but then goes to a constant low tone with no detection.

Everything is connected correctly but did see where the bs170 may have different pinouts, not exactly sure how to check that to make sure it is placed correctly but I did connect the scope and added some shots below.

It looks as though it has the pulse, the flyback and the pulse at the gate of the fet so not sure what to look for as what may be causing the issue other than the bs170.

Any ideas??

voltages below along with scope pics.

LM318
1 = 8.0v
2 = 2.09v
3 = 2.51v
4 = 0v
5 = 8.65v
6 = 9.48v
7 = 10.30v
8 = 0.71v

16F1824
1 = 5.01v
2 = 0.19v
3 = 0v
4 = 0v
5 = 4.78v
6 = 0v
7 = 0v
8 = 4.77v
9 = 4.76v
10 = 0v
11 = 2.45v
12 = 2.36v
13 = 3.17v
14 = 0v

(all voltages are +v or 0v unless otherwise marked)

pics

[ripsdevala]

Did you keep the coil away from everything - in the air - after switching on the detector ? That is when the calibration is started.
I never had this experience, but then again we don't have "iron"sand on the beach...

What did you do differenc compared to your previous beach test that did work?

Yes, i use all the procedures, last time its okay, doesn't get emi with almost at max sens, there is no black iron sand, crowded beach many garbage on small beach.
On latest beach, much washed iron sand bellow beach sand surface, navy base near there, long...long beach, few tourist, isolated beach
Or maybe I use 11v 8xAAA battery

I saw a photo on (I think) this forum of a guy who cut off the handle end of a cordless drill and attached it to the end of his MD by the arm rest and then used the drill battery to power the detector. There are several choices for voltage including 12.2V and 14.4V. You can easily detach the battery and put it in the charger at the end of the day. I've thought about building one like this, but have never got around to it.

That was good idea, but what about battery protection, if the battery discharge bellow recommendation its will broken, that's what I know. Or should use it with the battery housing from cordless drill pack, I think there should be PCB protection there, never open mine.

[morganton]

Let me try to find that module at local ol shop, or charge battery externaly for the last option.
Pikini is very picky with voltage i think, i will try 14v to make it last longer.

I saw a photo on (I think) this forum of a guy who cut off the handle end of a cordless drill and attached it to the end of his MD by the arm rest and then used the drill battery to power the detector. There are several choices for voltage including 12.2V and 14.4V. You can easily detach the battery and put it in the charger at the end of the day. I've thought about building one like this, but have never got around to it.

[BC547]

Did you keep the coil away from everything - in the air - after switching on the detector ? That is when the calibration is started.
I never had this experience, but then again we don't have "iron"sand on the beach...

What did you do differenc compared to your previous beach test that did work?

[ripsdevala]

Good day Bernard sir

I was on the beach yesterday for 3 hours, this detector cant withstand iron sand, the only way is to decrease the sens so it will reject iron sand, when i try to 2.5cm brass coin it detect at 15 cm with low sens, not a half of 10k resistor, when use more sens, it will beeping continuously, on the beach the detector behave almost like at home, its somekind get emi interference there, its a shame I don't have the video, I lost part of my shaft on the way there.
And I can't find anything, even a nail.... Idk

[BC547]

Nice video, morganton
Now for a complete detector and a video from the beach !

Best regards,
- Bernard

[morganton]

Good vid morganton. A bit of narrative would've been good- a bit hard to judge the distances. Bernards baby is a worthwhile project.

Yeah, I stumble through youtube videos so much that I just thought I would leave off. But here are the approximate depths:

Quarter about 20 cm.
Dime about 15 cm
Nickel about 18 cm
Penny about 16 cm
.304 gram gold about 3 - 5 cm

It will detect my pocket knife about 35 cm (forgot to show that in the video).

This is in my dining room with, I'm sure, lots of electrical interference around.

[Tim]

Good vid morganton. A bit of narrative would've been good- a bit hard to judge the distances. Bernards baby is a worthwhile project.

[morganton]

Video of Pickini 4

I have uploaded a youtube video of my partially constructed Pickini 4 showing the start-up sequence and air detection of a U.S. quarter, dime, penny and nickel as well as a .304 gram flake of gold.

Depending on your hearing, you will probably need to turn your PC speakers volume up to hear the startup and detection tones. I apologize for the quality of the video (hard to hold the camera and operate the detector at the same time), but hopefully it will give you some idea of the detector's capabilities.

https://youtu.be/a0LL7zn0drU

I still need to put the coil in its housing and finish building the stem assembly, etc.

The coil is 21 cm diameter, 23 turns of 26 AWG enameled wire, 310 uH, 2.1 ohms. I used mylar for the shielding.

I want to thank F117 and the other contributors for a great project and the help I needed to get it running.

[ripsdevala]

Let me try to find that module at local ol shop, or charge battery externaly for the last option.
Pikini is very picky with voltage i think, i will try 14v to make it last longer.
Btw i already try many coils from 310uh 1.3R, 340uh, 360uh, 430uh, more industance have a lower emi effect and low sens, lower industance more sensitive with stronger emi effwct.Cmiiw

[Tim]

I see, any idea how to charge 3 series LiLon with auto discharge and battery protection?

Here's a couple of options ripdevala. I use the one off Ebay. Bat+Bat2Bat3 Neg(miss Bat4). P+andP- go to charger. I use a 1.5w 12v solar panel mounted on stem, or you can charge from any un-regulated 12v supply. No fancy expensive chargers needed.
4amp, so you can also hook P+/P- to circuit. (The reg in green tape was omitted once I changed 7660 for 1054).