PlayStation 2 Analog Buttons

[Duane Degn]

I read, a while back, on Wikipedia, the buttons on a PlayStation 2 controller are pressure sensitive.

None of the PlayStation 2 Objects I've seen use the pressure information. Since I hadn't seen any projects or objects that treated the buttons as analog inputs, I figured Wikipedia was wrong about the PS2 controller.

In attempts to modify one of the PS2 objects for a recent project, I learned that the PS2 controller does indeed have pressure sensitive buttons. With the help of the internet, I've got the Prop to read these (12) analog button values.

I personally think it is pretty cool to have this additional level of control from the PS2 controller. I have no idea how I'll use these analog buttons in any of my current projects, but I like knowing they're there.

I thought some of you might be interested in this information.

Are there any objects for the Propeller that read the analog button values? If not, I'll make sure and post the modified object.

Edit: Now in OBEX.

[Mark_T]

Good source documentation for PS2 controllers are here, if anyone's interested: http://www.geocities.co.jp/Playtown/2004/psx/ps_eng.txt and
https://docs.google.com/View?docid=ddbmmwds_5cw4pk3

[Duane Degn]

Mark,

Thanks for the links. The first link included a space character at the end that kept my browser from finding the correct page.

This link should take people to the correct page.

The second link took me to a Google Docs login page.

I'm just about finished with my demo showing off the analog nature of the PlayStation 2 buttons. I'll be uploading it soon.

[Duane Degn]

Attached is the modified PlayStation 2 object and demo.

Here's the output from the demo with the analog buttons turned on and with the square, circle and right arrow buttons pressed.

 Press "d" to enter digital mode.
 Digital mode will turn off the analog buttons.
 Press "a" to enter analog mode.
 Press "b" to change to analog button mode.
 If not all ready in analog mode this option will change
 the controller to analog mode.
   Mode: Analog                    Joysticks and analog buttons in use.
                  Left             Right
               x:108 y:138      x:133 y:131
   Buttons:  Sq   X    O    Tri  R1   L1   R2   L2
   Digital:   1    0    1    0    0    0    0    0
   Analog:  126    0   66    0    0    0    0    0

   Buttons:  <    v    >    ^    St   JR   JL   Sel
   Digital:   0    0    1    0    0    0    0    0
   Analog:    0    0   57    0
   Raw: $5FDF5A79,$8A6C8385,$00000038,$7E004200,$00000000
   All Buttons: 01111111011111
   Last debug message: Turned on analog buttons.
   Last action:
   programName = dwdPs2Demo120424g

There aren't any methods to convert the raw data to joystick values. These conversions are done in PASM with the results written to hub RAM.

The parent object needs seven longs and 34 bytes to hold the controller information.

VAR
  
  ' Keep below in order and together.
  long psData[5], allDigitalButtons, debugLong
 ' Keep above in order and together.
  
  ' Keep below in order and together.
  byte rightX, rightY, leftX, leftY
 byte digitalButton[Ps2#_NumberOfControllerButtons]
 byte analogButton[Ps2#_NumberOfAnalogButtons], mode, dataSize
 ' Keep above in order and together.

Once the PS2 object has been started, it doesn't need to be called again except to change modes. The controller is continuously polled with the new data continuously written to hub RAM.

The demo will start out in digital mode (boring); you'll need to press "b" on the keyboard to turn on the analog buttons.

I tried to add comments to explain how to use the object. One thing to keep in mind is that there are three different sets of button data being written to the hub.

Here's a quote from the comments.

  The bits representing the button states are ordered
  differently than the bytes measuring the pressure of
  the analog buttons.  The program uses the same button
  order for both the digital buttons and the analog
  readings from those buttons.
  This reordering of the pressure data should make it
  easier to use with the digital button data.
  The button states are reported three different ways.
  The state of all 16 buttons are written to a long with
  each button being represented by one bit.  A low value
  in the button's bit position indicates a button press.
  The second set of button data is an array of 16 bytes.
  The normal state of these bytes is zero.  A button
  press with cause a one to be written to the corresponding
  byte.
  The third set of button data is held in a 12 byte array.
  The bytes in this array contain the pressure reading
  for each button.  These reading vary from zero (for
  no pressure) to 255 (full pressure).

I personally think it's pretty cool these buttons will output analog values and I look forward to using these buttons to control aspects of a robot.

Hopefully some of you will find it useful.

Let me know if any of you have questions or suggestions for improvement.

I do play to add control to the Dual Shock motors. I will also likely add a way of locking the controller in the various modes.

[Duane Degn]

I realize I never posted a link to the site that helped me the most with this driver.

The Curious Inventor has a lot of information about the PlayStation 2 controller.

I've read conflicting information about the controller. Is it a 5V device or a 3.3V device?

I'm currently powering it with 3.3V.

I know I've mentioned my dislike of generic controllers, but I thought I'd mention it again in this thread. The first controller I purchased was from SparkFun. I was disappointed to find the joysticks only had 5-bit resolution instead of the 8-bit resolution provided by the Sony controller.

I'd strongly recommend getting a Sony controller over a generic controller. The Sony controller only costs $5 more than the $10 generic. I just tried to find the $15 Sony controller I had seen on Amazon and I couldn't find it. This was the only normal black Sony PlayStation 2 controller I could find on Amazon and it costs $20.

I wish the reviews of the generic controller would mention how many bits of precision the used.

To be honest, I'm not sure how the 5-bits vs 8-bits would effect my use of the controller. It just bugs me on principle that the generic controller has less resolution the original Sony controller.

[Duane Degn]

I just added this to the OBEX.

http://obex.parallax.com/objects/861/

If any of you use PlayStation 2 controllers, I hope you give it a try.