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by Drop_C
Mon Dec 02, 2019 9:29 am
Forum: Other projects
Topic: Detect negative voltage on GPIO?
Replies: 6
Views: 795

Re: Detect negative voltage on GPIO?

That's interesting. I'll try that. Thank you very much!
by Drop_C
Mon Dec 02, 2019 8:46 am
Forum: Other projects
Topic: Detect negative voltage on GPIO?
Replies: 6
Views: 795

Re: Detect negative voltage on GPIO?

Thanks. Luckily I haven't tried yet to feed the negative voltage to a gpio :-) I should have mentioned, I have a whole row of these touch sensors, and I only need to detect the change in any one of them. In order to save some gpio pins, I thought I could electronically change there constant on/off s...
by Drop_C
Sun Dec 01, 2019 9:50 pm
Forum: Other projects
Topic: Detect negative voltage on GPIO?
Replies: 6
Views: 795

Detect negative voltage on GPIO?

Hi, the question is probably pretty dumb, but I just can't get my head around it: I need to detect change of a touch sensor (TTP223 IC), which gives a constant signal when it's touched and drops to ground when it's not touched. I tried a simple RC circuit which gives me a signal when it's touched, w...
by Drop_C
Sat Nov 22, 2014 4:08 pm
Forum: Automation, sensing and robotics
Topic: AM2302 sensor not working
Replies: 4
Views: 4817

Re: AM2302 sensor not working

I can't believe it, it's working, with http://www.raspberrypi.org/forums/viewt ... 75#p515575 !
Thank you so much!

Cheers,
Dominik
by Drop_C
Sat Nov 22, 2014 12:00 pm
Forum: Automation, sensing and robotics
Topic: AM2302 sensor not working
Replies: 4
Views: 4817

Re: AM2302 sensor not working

Thanks! Ok, 3V without pull-up is a variant I've not tried, yet. I'll give it a go. Just to make sure (and exclude some further test combinations), could someone confirm (or dismiss) my assumptions so far: DHT22 is the same as AM2302 No pull-up resistor needed for 3V operation No capacitor needed as...
by Drop_C
Sat Nov 22, 2014 11:17 am
Forum: Automation, sensing and robotics
Topic: AM2302 sensor not working
Replies: 4
Views: 4817

AM2302 sensor not working

Hi, has anyone this sensor running and can tell me, how he got it running? I tried everything I could find without success. The most promising so far was https://learn.adafruit.com/dht-humidity-sensing-on-raspberry-pi-with-gdocs-logging/software-install-updated , with these steps I got it working fo...

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