Analog values through analogRead()

Other Hardware Sensors
1

Hello dear Arduino community,

I have a question regarding analog values through analogRead(). I connected two copper wires, one to an Analog Pin 0 (A0) and one to GND Pin of an Arduino Uno, and started measuring on my fingertissue via analogRead(). As I opened the Serial Monitor, different values were displayed between 350-450. What do these values represent? Do they have a specific unit?

Thank you very much in advance for your help

Best regards

Kosta

2

Assuming you have a UNO, they represent the measured difference of potential (Voltage) between the 2 wires, on a 10 bit sampling scale (ie 0 means 0V and 1023 means 5V if your arduino is powered with a stable 5V)

Beyond your skin/body capacitance, the wires act as antenna as well so what you measure is just hard to qualify noise

3

Hello J-M-L,

thank you very much for the information. So I measure a potential in a millivoltage (mV) range?

Thank you very much and have a nice day

4

if you get on average 400 it means almost 2V (in the interval [5V x 400/1024, 5V x 400/1023[)

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