I'm currently working on a project that makes use of existing components on a wireless Xbox 360 controller. I've disassembled the controller and located several connections including LS, RS, LT, RT, LB, RB which I need to use for my project. My problem is, which I'm sure is a simple solution, I don't know how the 2-axis potentiometer works on the controller. I've attached a picture of one of the two axis of the potentiometer, the second picture is where the leads connect to the PCB on the other side of the board where I've made connections to test.
What do each of the pins on the potentiometer do?
Did you cut the traces on the circuit board that are associated with the joy stick? If not, you are also connected to the existing components of the x-box controller. Beyond that, your Ohmmeter will tell you how the device operates.
Paul
No I kept them in tact. I am powering the board with a power supply and figured power would run through the board to the potentiometer and I could sort of piggy back off of it and read the signal. When I connect it to an Arduino and graph I get values between a certain range but there is so much noise and it doesn't react when I move the potentiometer so I mist have wired it wrong.
So I ripped one of the triggers off and tested it. I found that VCC and ground are interchangeable on the left and right pins, while the center pin is for signal to the analog inputs on the Arduino. My question now is why is there so much noise and inconsistency when the potentiometer is connected to the controller motherboard? Obviously the controller is reading the data and processing it, I'm just confused about what is causing this problem. Let me know if you have any insight, thanks.
michaelberge:
So I ripped one of the triggers off and tested it. I found that VCC and ground are interchangeable on the left and right pins, while the center pin is for signal to the analog inputs on the Arduino. My question now is why is there so much noise and inconsistency when the potentiometer is connected to the controller motherboard? Obviously the controller is reading the data and processing it, I'm just confused about what is causing this problem. Let me know if you have any insight, thanks.
Now you are just being silly! Without a schematic of the controller, how can anyone give you any advice other that to completely remove the pots and then play with them.
Paul
Now you are just being silly! Without a schematic of the controller, how can anyone give you any advice other that to completely remove the pots and then play with them.
Paul
Please don't say that's silly I don't think you understand what I'm looking for. I'm sure there are people who have have worked with Xbox controller circuitry. I'm not an electronics engineer, I'm a software engineer so I have little knowledge on how complex circuitry works. I don't need to know what exactly is the root of the issue, but that something attached to the potentiometer somewhere else is affecting the values, that's all I need to know. If this is happening to me I'm sure someone somewhere else has had the same problem, it doesn't require a diagram it requires experience.
I looked up the circuitry of the old IBM PC game controller. They used the joystick pots to change the frequency of two separate digital oscillators. The pot positions were read by chips that measured the pulse length of each oscillator and determined the pot position from that. You would only know that by reading the documentation that includes the schematic.
Same applies to your controller. Here you are using an Arduino to measure a DC voltage when in fact the POT may or may not have a DC voltage. They may be controlling the discharge time for a capacitor, hence not a DC voltage.
Paul
