Arduino Uno user here

I am building a project with 4 analog inputs A0 dose not work. A1 A2 and A3 work perfectly fine! But for last input when I connect to A4 or A5, then they do not go to zero. They are stuck between 400 to 900. Even when connected to arduino ground it gives 400 instead of 0.

Am I missing something here cause the circuit for A4 connected to A3 gives perfect input value. They both work fine as output. Same situation with A5.

Is there another way to get one more Analog Input without multiplex?

Thank you!

  • Circuit is simple... Just 4 potentiometer and 4 pwn leds. – Abhishrant Majhi Mar 15 '15 at 18:02
  • I mean the circuit on the Arduino board. – The Photon Mar 15 '15 at 18:53
  • A 0 is a normal pin. A 4 & 5 are also the i2c data and clock, but that only depends on if a shield is connected – Passerby Mar 15 '15 at 19:04
  • What do A4 and A5 report when you connect it directly to GND? What sensors are you using? – AMADANON Inc. Mar 15 '15 at 19:29
  • A1 to 3 gives zero... A4 and A5 give 440 approx... All input connect to diff RC pass filters.. – Abhishrant Majhi Mar 15 '15 at 19:37

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