Analog input already having a reading when nothing is connected to it

[skcareer]

Hi Tino,

Thanks for your great work!

I was trying to implement pyFirmata for the first time, but i was reading even when no voltage signal is connected to the assigned analogue input.

Please find my code below:

!/usr/bin/python

from pyfirmata import Arduino, util import time

board = Arduino('/dev/ttyACM3') it = util.Iterator(board) it.start() analog_pin = board.get_pin('a:2:i') analog_pin.enable_reporting() led = board.get_pin('d:13:o') while 1:

   reading =  analog_pin.read()
   if reading != None:
             voltage = reading * 5 
             print("Reading = %f\tVoltage = %f" %(reading, voltage))
             led.write(1)
             time.sleep(1)
             led.write(0)
             time.sleep(2)

Looking forward to receiving your possible support

Thanks in advance.

[tino]

Analog ports will have "noise" or "float". You will see the same when you run this directly on the board.

You can "silence" it by connecting the port to ground.