Tweet
and thats the layout i have used
has anyone ever succes with one of the pi projects from itmd???
has anyone ever succes with one of the pi projects from itmd???
-
-
This may have nothing to do with your problems, but it looks like you are running the PIC121840 with 6.24V across the supply pins. According to the data sheet the Operating Voltage Range is 2.3V to 5.5V. The paragraph at the bottom of page 181 mentions the need to keep the supply voltage within limits.Comment
-
No Gwil. From the book, voltage should be fine, as using half the supply. -VB to central voltage earth.
Can't be too far out, if PIC is controlling the pulsing OK and modulating the speaker tone.
(I'm still playing with PI-1, having got it working on breadboard. So can't help further)
RayComment
-
I may be experiencing Brain Failure, but the voltage across the PIC supply pins (pins 1 and 8 ) still doesn't look right to me. My copy of the data sheet says the maximum supply voltage is 5.5V. The measured voltage between them was given in post #30 as 6.24V, which makes sense of course as this is derived from half the supply voltage - in this case 12.5V (post #30 again). I'm not saying that a 6.24V supply will kill the chip, or necessarily cause a malfunction, only that it isn't a good idea.
To quote the paragraph I mentioned: "Keep in mind that power to the PIC is derived from half the battery voltage and should not exceed 5V, therefore the battery voltage should not exceed 10V. If you want to run a higher battery voltage then you should add a voltage regulator (such as a 78L05) for the PIC." This battery voltage issue is also mentioned on page 166.
GwilComment
-
The schematic says a supply voltage of 9volts, that would put about 4.5 volts across the picCan anybody tell me what i should hear if i start the unit. i powered it with 18650 pack with 12,5 voltsComment
-
i tested also before wih 9v block, but that doesnt work so i take my Standard pack of three 18650 cells for test
i should at least hear something like a Startup Sound from the pic Audio out when i connect the battery, or not?
i have to read the book again and againComment
-
Sorry Gwil, you are quite right. I went from the book 9V. I had been playing with 12V (PI-1) and failed to take in the voltage readings as significant.
There is a warning in the book about not exceeding 10V to preserve the PIC. This is in the PI-2 notes, and there is also an earlier note somewhere advising that only PI-1, (without the PIC) is suitable for more voltage. (And the PI-1 case is suspect, as a chip is already beyond its rating).
RayComment
-
Any in-depth questions will need to go to Carl, as he wrote Chapter 12 (except for PI-5).
However, the datasheet states that the supply voltage range for the PIC12F1820 is between 2.5V and 5.5V. In that case, a split supply created from a 9V battery should be ok.Comment
-
Thats a good question as I have not had a chance to test my new 1840 chip since I programmed it a couple of weeks agoi should at least hear something like a Startup Sound from the pic Audio out when i connect the battery, or not?
if I cannot get any audio from it I am giving up on the project. Hoping to test the chip next week.Comment
-
If you want to run PI4 above 9V, then I suggest replacing R28 with a 5V (or slightly less) zener.Comment
-
thanks
i will buy some zeners
maybe i will add a voltage Regulator in future Projects
but can you say me what i should hear if the detector starts correct
a short beep or does it start to click ?Comment
-
It should have a low threshold buzz.Comment
-
i got it
have to re-program the pic controller and then used a 9v block
for more infos read the video comment please - i have no advertising on my videos
Comment
-
Well done, Bernte.
---------------------------------------------------------------------------------------------------
Jealousy is toxic poison to your soul.Comment
-
Congratulations Bernte_one can you please tell us the software program that you used to program the pic, thanks.
also would it be possible to share the pcb layout file ? thanks.Comment
Comment