Reply to Touchpad Foolery

Thought I'd post some information on my work with touchpads this last week as others may find some of this information useful. My friend gave me a non-working HP Pavilion. I wanted a touchpad in an Arduino project I have in mind. You can easily wire most touchpads to a PS/2 or Serial (9-pin), and even old school AT!

Removal can be a bitch. On the HP, it was secured by screws under the bezel and glue. I shot it with a hair dryer for 10 minutes to heat the glue and managed to pry it off with out harming anything. (You could also purchase one off ebay)

After I got it out I Googled every number on the back and discovered I was the proud owner of a Synaptics TM41PUZ307. Synaptics has a great resource for helping you determine the pinouts of many of their models HERE My Synaptics TM41PUZ307 wasn't on the list, but an internet search turned up this:

• pin5/6 = GND
• pin7/8 = CLK
• pin9/10 = DATA
• pin11/12 = +5V

I chose to wire to a PS/2 cable I salvaged from a broken keyboard to test if this was even gonna work. I used a razor blade to separate the flat cable into it's different connections and soldered to the cable. TIP: Use warm solder, if it's too hot you'll just melt the flat cable. I plugged it in the PS/2 port on my desktop quickly and the standard windows mouse driver worked just fine. Without installing any drivers, I was able to navigate the mouse, left click, and use the mouse scroll wheel. I mounted it on my keyboard for now. I tried installing the touchpad driver from HP's site, and the generic driver off Synaptics website, but neither found a device. I was hoping to be able to run Touchpad2Midi at least. I'll post here if I have any success.

Applications:

• There are a host of applications that will convert a PC mouse to a Midi device. You can find a list HERE
• To use with USB you'd need to buy (or make?) a 'USB to PS/2 Keyboard and Mouse Converter'. You could also solder into a wireless mouse.
• I plan on eventually using it in an Arduino project. Details on interfacing a trackpad to an Arduino can be found HERE See a project HERE

Use a multimeter to confirm what the pinout of the PS/2 cable is.
Your wire colors may differ, mine where as follows:

• pin1 = DATA = Red
• pin3 = GND = Grey
• pin4 = +5V = Brown
• pin5 = CLK = Yellow

Or, you can wire to a 9-pin Serial port old school mouse style. This is also nice idea to use on a desktop as a secondary mouse.

• pin4 = DATA
• pin5 = GND
• pin7 = CLK
• pin8 = +5V

*You could even wire to an AT keyboard.

I'd like to learn if there are other ways of decoding the mouse data to control X/Y coordinates. Can you convert the data to control two potentiometers at once an easier way then using an Arduino?