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Problem: GPIO debounce not working
(06-29-2019, 09:12 AM)Jewa_TWN Wrote:
(06-25-2019, 08:19 AM)Jewa_TWN Wrote:
(06-24-2019, 01:20 PM)Tim Curtis Wrote: I don't disagree however I'm not the dev responsible for the GPIO class library used in moOde's GPIO Buttons module. You would need to contact the maintainer of RPi.GPIO

The script used in moOde is located in the directory below


Send the request / feedback to the maintainer of the RPI.GPIO
Once I got feedback, I will post it here.

For the meantime to "solve" my issue, i will invert the signal:
I will use a N-FET to have the GPIO at 0V (solid!!) when the supply is ok.
(The FET will five me a few milli-ohm connection, iso a 2K pull up)

This should reduce the EMI influence. Its not good, but should work.
Most likely after the weekend.


Update after the above:

NO reply from the GPIO maintainer yet :Cry a pity..  

Hardware changes:
Added a extra FET, to invert the signal:
The solid N-FET  + 330nF cap between Drain & 0V (0V when supply OK, 3V3 when about to shutdown) helps, but sensitivity is still there for touching the enclosure.
(Due to ESD discharge, as im walking on slippers indoor :-))

Next option is to solder a cap directly on the PI, not really preferred..

Keep you posted.

Slightly modified the PI...

Added a 1uF (0603 size) capacitor & 1K resistor between GND & the GPIO pin, directly on the board.
The 0603 nicely fits between the pins, & utilizes the GND pin/plane beside it. Cant get any shorter on the board Big Grin 
Next, a 680-Ohm (trough hole!!) resistor to connect to the "UPS mode" signal.
A SMD resistor will not hold with a wire.

Reason to use 1K & 680 Ohm network, is that in this way I can use 5V signals. (gives 3V on GPIO, when 5V is applied)
Second, it has a pretty low impedance.

Pictures attached, for those who want to try as well.

Will try this modification for a while, then post if it works.



Messages In This Thread
GPIO debounce not working - by Jewa_TWN - 06-23-2019, 07:16 AM
RE: GPIO debounce not working - by Tim Curtis - 06-23-2019, 12:55 PM
RE: GPIO debounce not working - by Jewa_TWN - 06-24-2019, 07:12 AM
RE: GPIO debounce not working - by Tim Curtis - 06-24-2019, 01:20 PM
RE: GPIO debounce not working - by Jewa_TWN - 06-25-2019, 08:19 AM
RE: GPIO debounce not working - by Jewa_TWN - 06-29-2019, 09:12 AM
RE: GPIO debounce not working - by Jewa_TWN - 07-20-2019, 09:39 AM

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