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Topic: Constant voltage on analog input pin (Read 217 times) previous topic - next topic

Mugga

Hello,

I've got an arduino micro and wanted to ask if I can apply a constant voltage around 1.2v to an analog input pin?

What I'm trying to achive is controlling a wireless power socket using the PS_ON pins on an Duet Wifi. The PS_ON pin, is connected to ground when it should be on. But when its off I get a voltage of around 1.2v.

And I just wanted to be sure that when my 3D printer is off for several days, I don't get into trouble when the arduino gets a constant voltage at the analog input.

MarkT

The Arduino will be powered up all the time?
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

Mugga

Yeah, arduino is constantly powered via usb

DVDdoug

If it's powered-up it's fine!

"Funny things" can happen if you put voltage on an unpowered chip.   You can put a resistor (1K - 10K) in series with the Arduino input to limit the current under "unusual" conditions.  (Normally, the inputs are around 100 meghoms and virtually no current flows.)

FredScuttle

Sounds like an open collector output, are you using the analog input pin as a digital input? If so you need to enable the internal pullup resistor in setup().
Code: [Select]
pinMode(A?,INPUT_PULLUP);
Awww! Who needs an instruction manual to use a simple chain sa......

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