Reading from an RC remote stick's potentiometer

Other Hardware Sensors
1

Hi!

I've encountered some problems involving my attempt to read from the potentiometers of one of the sticks on an RC remote.
The pot has 3 pins (Red, Yellow, Black). I've connected red to 5v on the arduino, yellow to an analog pin and black to ground. The yellow one is also connected to ground via a 10k Ohm resistor.

Ideally I would want a the voltage to increase and decrease linearly. However, the readings I get are at 4.2V idle, 4.1V min and 4.33V max. I'm probably solving this by software somehow, but I'm not sure how I would map it, since all I can really tell is what the voltage is at min, idle and max.

The second problem is i find the precision could be higher. My first thought of a solution is to have the voltage offset and amplified to better map to the analog inputs. But how would I go about and do this?
i.e. bring the current range of 4.2-4.33V to say perhaps: 0.5-4.5V?

2

Can you post a drawing of the schema??

3

Kniben:
The yellow one is also connected to ground via a 10k Ohm resistor.

Here is your issue: you are altering the voltage bridge effect of the potentiometer.

I would recommending comparing your circuit to the following example: http://arduino.cc/en/Tutorial/AnalogReadSerial. It covers the correct way to connect a potentiometer circuit and show how to read it.