Hacking touchpads

I'm going to make project that involves touchpad. I had broken netbook laying around, so I decided to use it's touchpad. It was Asus eee 1000H, touchpad was made by Elantech. It had some testpoints, so I figured out which is which. TD and TC are respectively data nad clock. Vcc and GND (TP1 and TP2) was easy to find. GND it was connectd to ground plane, Vcc was bold track comming from connector, and had cap mounted beetwen it and GND. I connected it to arduino, but unfortunetly something was broken, because I always get movement values equal 0 and only time I get any values (zeros) was when I connected it properly.


For Arduino code I used example PS/2 mouse library (you have to replace "WProgram.h" with "Arduino.h" in ps2.h).
I didn't give up and I went to local laptop service. They gave me four Synaptics touchpads two of them with T1006 chips (only one on photo). I found it's pinout on Sparktronics blog:
Pin 02 : DATA
Pin 03 : CLOCK
Pin 06 : SCRL2 (LEFT)
Pin 07 : RIGHT
Pin 08 : LEFT
Pin 09 : SCRL4 (DOWN)
Pin 10 : SCRL1 (UP)
Pin 11 : SCRL3 (RIGHT)
Pins 14-28 : COLUMNS 0..14
Pin 29 : GND
Pin 31 : EXT. CAP
Pins 32-37 & 41-43 : ROWS 0..8
Pin 44 : VCC (+5V)
Pin 45 : GND

For simple PS/2 you'll need only Vcc, GND data and clock. Other pins can be used for other purposes.

Despite T1006 touchpad I get two with "blob" ICs: Synaptics 920-000702-04 (biggest with frame) and 920-001809-01 (one without wires). Same way that with Elantech I figured out where power pins were. In all four of them T22 was Vcc, and GND was pretty obvious: TP on ground plane and pad for not populated capacitor connected to ground plane. Data and clock was conntcted to ribbon cable. I had to figure out which ones were them with trial and error method. Fortunetely one touchpad had only 4 wires in connector , and second had six, but I found Vcc and GND, other 4 wires was arranged it two couples.  

Here's pinouts for touchpads I have:
920-000489-01 (with T1006) from HP Compaq nx8220 part no.: 6070A0097701
Vcc - T22
GND - T30
data - T11
clock - T10

920-000702-04 from HP Pavilion entertainment PC probably: DV9000 17.1"
Vcc - T22
GND - C6 pad / big ground pad
data - T11
clock - T10


920-001809-01 from Acer Aspire 5750G
Vcc - T22
GND - T23
data - T12/13
clock - T13/12
I forgot which was data/clock, I can't check it now, because I broke this touchpad. I bent it too much when I tried to remove it from palmrest.

I think that almost all Synaptics touchpads are PS/2 compatible. Additional wires in ribbon cable can be connected to buttons' switches or controller's scroll signals, so it should be safe to use trial and error method to define data and clock signals. 




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