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Suspected noise on push buttons

Posted: Tue Dec 14, 2021 7:58 pm
by WingNut
Can anyone help with suspected noise on push buttons. I'm using 3 buttons for a menu but one of them and occasionally a second don't respond as expected. When I put my hand near the wires of one of the buttons the lcd flickers and the menu reacts as if i have exited the menu. Almost as if a button has been pressed. I'm using active high and a 1k and 10k resistor as per a diagram from older flowcode forums. Should I use a cap from each of the pins of the pic to ground and what value would it be? Its difficult to tell if the code is working properly as it appears like a reset from the particular menu item

Re: Suspected noise on push buttons

Posted: Tue Dec 14, 2021 8:16 pm
by medelec35
It sounds like you could have a poor joint between the microcontroller input, 10K resistor and GND.
You could try removing the power and measuring the resistance between the VSS of the Microcontroller and the input pin.
Make sure it's 10K.
If it is then check that the input pin matches the corresponding input pin of your flowchart.
You could just have the correct pin floating by mistake?
If it matches then try reducing the 10K to 5K6 or even 4K7.

Re: Suspected noise on push buttons

Posted: Wed Dec 15, 2021 6:12 am
by WingNut
Thanks martin. I'll go over it all today

Re: Suspected noise on push buttons

Posted: Wed Dec 15, 2021 6:26 am
by WingNut
Solved. Even more fundamental mistake. I'd soldered 2 of 3 resistors to the same pin :shock:
Eyesight is not what it used to be. Thanks again Martin

Re: Suspected noise on push buttons

Posted: Wed Dec 15, 2021 7:56 am
by medelec35
You're welcome.
That's brilliant you have found the issue, well done.
Hardware mistakes are easily done by anyone.
Thanks for updating us.