Hi,

I am attempting to interface a joystick that has two pins for each axis (like a normal resistor, except variable) to my μC's (ATmega32) ADC. My problem is that, I cannot figure out the proper way to connect it. I have tried connecting one pin to 5v and the other to my μC, but that yields no results.

Any help would be appreciated!

 

A simple way would be a voltage divider.
Basically connect one of the 2 pins to ground and the other pin to the ADC channel and also to 5V through a fixed resistor. Pick a resistor that is maybe about half the maximum of the variable resistor and experiment from there.

 

Okay, I have a voltage divider up and running, but the voltage on the ADC isn't changing enough(changes about one volt) to get a precise reading. Using the internal amp on the AVR results in a value of 255 no matter where I move the joystick.

Thanks!

 

Are you sure that joystick has an analog output? You should be able to feed it 5 volts and ground, and the outputs of both axes should be a voltage that varies from 5 volts and ground.

With two pins, yours sounds like it might just have switches.

 

Yes, I am sure it is an analog joystick. This is the joystick I am using: http://www.sparkfun.com/commerce/product_info.php?products_id=9426

Seems like it has a small variance in resistance (2k - 5kΩ). So, is there any way to increase the "variance" of the joystick?

 

According to the link, you put power to pins 2 and 4 (that would be ground and +5), and the other pins are the X and Y axis signals. You should be able to read the voltage outputs with a meter to see if it works properly - checking for resistance is not telling the whole story.

 

Thanks - I did not understand what they meant by "supply power"; it is now working great!