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I salvaged this touchpad from an old laptop and I would like some ideas for using it, I thought about using it as a light dimmer for two sets of lights. Does anyone know how it works? I'm sort of a newbie but I'm willing to learn.

Where can I find its data sheet? Here's the print on the back

ALPS 94v-0
JCI-S1S H
56AAA1865C

(in case the images aren't clear)

There is a small IC under the tape : 1CA017A 0B/U234

enter image description here enter image description here

The touchpad came from an old Acer laptop, I don't remember the specific model anymore -- very old, AMD Athlon and 1 GB RAM and a floppy drive old.

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If the laptop worked you might want to plug it in and plug a logic analyzer or an oscilloscope to the pins of it to snoop what sort of information it's sending.

Even if you can't plug it back in the laptop, if you can figure out the power supply voltage and pins it might start sending data even without an external clock signal.

Here's a link that might be of some use, seems to go into detail - http://www.synaptics.com/sites/default/files/511-000275-01_RevB.pdf

And perhaps this can be applied somehow as well, although seems like the connector has more pins. http://pinoutsguide.com/Inputs/alps_touchpad_pinout.shtml

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Trackpads generally come in two flavors. PS/2 and USB. A few can come in direct/analog mode, but those are very hard to find.

From the age of it, it's probably PS/2. 5v VCC, Gnd, A Data and a Clock pin. VCC and Ground should be easy to find. The other two are slightly harder. Basically you will have to use a multimeter to narrow it down, then guess.

See http://runawaybrainz.blogspot.com/2013/04/hacks-reuse-laptop-trackpad.html for an example of a old PS/2 Synaptics touchpad being used with an Arduino. Or you could wire to a computer.

Update: This site (Google Translate) has the same thing planned as you. Same board, maybe different minor revision. They have done a pinout of the 1CA017A ic, and wired a ps/2 connector. enter image description here

(Also, you didn't mention which laptop it came from).

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  • \$\begingroup\$ actually i wanted both yours and linards' answers but i have to give the best answer to linards because he gave a detailed electronic specifications and even an interfacing guide and you gave a great project implementation thank you both \$\endgroup\$ – workoverflow Aug 31 '13 at 10:42

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