PICKINI - an easy to build PI detector

[bernte_one]

i just hear the startup tone and no ticking sound
get 8v on the pin3 lm318

were should i start to search the failure?

[F117]

When You look here:
http://www.geotech1.com/forums/showt...detector/page3 -- post #60
All DC voltages are mentioned.
It looks like there is something wrong with the input -- the microcontroller does not get a flyback pulse after sending the first switch-on pulse.
The coil - input opamp - clamping diodes --- check the polarity of C9 = coupling capacitor to opamp input.
Hope this helps,
- Bernard

[bernte_one]

hello
i have used hispalbas layout - that was not good
missing connection
from coil (upper coil marking) to +rail from cap C6
not funny

and i still have two 1k resitors parallel to coil
because i had jumped the post where it was written to replace them bei 470r (i think a least 1W) dampening resitor
typical file salad
and i lost the overview
will start it with a new board i think

and after finishing i will write an how to send the hexcode to the pic manual (had waste some yours with experimenting and it was so easy when you would know where to set the marking in the new mplab 1.9)



thanks bernard for fast reply and help

[F117]

This is my original layout that works:



On Your layout, there is no connection between the +12V rail and the coil.
You can add a simple wire bridge to solve this.

You can use 2x1K in parallel ( normal resistors) as dampening resistor - instead of the single 470 ohms resistor.

Best regards,
- Bernard

[bernte_one]

some pictures of my crap board

[baum7154]

How do we determine the time constant of our target in question? I try to read everything you and Eric write. In those post's I see TC alot,but I dont completely understand the principle.

If you have not already done so you should read the Target Time Constants thread in this Tech Forum. It addresses some typical T/Cs and also gives some info on repeatable Time Constant Standards made from aluminum can and heavy duty aluminum foil. These standards are valuable in testing the capabilities of a detector especially if you are trying to detect small gold targets.

Good Luck

Dan

[6666]

Bernard
in post #199 your pcb has large earth planes on it, but when I view the pcb from your site they are missing, did you remove them ?

[F117]

When You open the PCB file in Eagle and You right click on the ground trace and select "ratsnets", the ground plane [ the dotted outline filled ] should appear.
I never succeeded in saving the layout in Eagle with the plane visible

- Bernard

[6666]

Bernard
Thanks that information works.
Now with grid off, rats nest on, layers 16,17,18,19,20 all on
I now get this

[bernte_one]

hello
can i replace the pic 16f1824 with the 16f1825 ?
easier and cheaper to find

regards

[johnandles]

hello
can i replace the pic 16f1824 with the 16f1825 ?
easier and cheaper to find

regards

I received 2 samples from microchip...free
regards
john

[F117]

can i replace the pic 16f1824 with the 16f1825 ?
easier and cheaper to find

Not sure why you would want to do this:

With Farnell (Germany): 16F1824 = 1.44€
http://de.farnell.com/microchip/pic1...dip/dp/1814944

16F1825 = 2.08 €
http://de.farnell.com/microchip/pic1...dip/dp/2045294

[surprised] ??? [/surprised]

Regards,
- Bernard

[nick holas]

16f630

hi all
F117 i think i could replace your 16f616 by 16f630 because when reading their datasheet they are very cross (same pinout),so have you got an idea of what i have to change in your hex (16f616) to burn in my pic (16f630) ?
thanks

[F117]

Nick,
I don't think you can change the hex file like this.
Starting from the sources you could recompile for another controller.
But again, the 16F616 is commonly available.
here eg:
http://fr.farnell.com/microchip/pic1...?ref=lookahead

[Dixix]

I know this only from the AVRs. For example, you can get a ATmega88 instead of inserting an Atmega8. But then you have to change something in the software. For example, hardware and software stack. You also have to tell the program the other chip. This changes also (though only slightly) the HEX.ffile after the compile.
In PICs it will be safe like that ...
Dixix