Linear Sensor has different behaviour at certain analogue ports

Other Hardware Sensors
1

Hi there,

I'm using an linear slide sensor. Using it at analogue port 0 to 3 everything is fine and the incoming data is linear.
Using port 4 or 5, the data is not longer linear but seems to be logarithmic!
Is this a hardwareproblem - I was tinkerin quite a while with this one - with external reference too - did I shoot my board??

Greetings,
Stefan

2

All the analogue pins go to the same A/D converter - what else is attached to the pins?

3

in my project there is an accelerometer and a gyro attached - but i also tried it all alone with nothing else attached to it - same result :frowning:

4

Pins 4 and 5 on an ATmega328P are also the I2C pins. Perhaps try disabling the pullups on these lines? (I believe the Arduino startup code automatically enables them).

digitalWrite(D18, LOW);
digitalWrite(D19, LOW);

--
The Ruggeduino: compatible with Arduino UNO, 24V operation, all I/O's fused and protected