Raspberry Pi Forums

Posted: **Fri Mar 03, 2017 7:42 pm**

Hi,

i am using a RPI3 with a rain gauge.
If there is enough water in it, it will go from High to Low.
If i test it by tipping the rain gauge it works perfectly, but sometimes it calls the interrupt routine by mistake.

Code: Select all

GPIO.setmode(GPIO.BCM)
GPIO.setup(8, GPIO.IN, pull_up_down=GPIO.PUD_UP)
GPIO.add_event_detect(8, GPIO.FALLING, callback=InterruptRoutine, bouncetime=200)

We already use a 95kOhm resistor at the 3,3V.
Any idea?

Posted: **Fri Mar 03, 2017 7:58 pm**

Hello,
shorts between cables, bad solder junctions.
Long wires will collect all sort of radio or magnetic influence. Use twisted wires, perhaps shielding; RC low pass filter, protection schottky to VCC, GND.
If "tipping the rain gauge" results in signals, perhaps there is a bug crawling around ? Storm, or a pecker or racoon ?

Regards,
Gerhard

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Interrupt routine calling randomly

Interrupt routine calling randomly

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