Cheap touchpads...

**mushin** · 09-09-2004, 06:34 PM

Some assembly required

http://cgi.ebay.com/ws/eBayISAPI.dll...e=STRK:MEWA:IT

Seriously, these are dirt cheap PS/2 pads for those who can do the little (both size and quantity) soldering required to attach it to a PS/2 connector. I've figured out the pinouts, so you don't need to.
(Disclaimer: I have nothing to do with the the seller, besides vouch that my order came through good.)

By the way, hello all! I've been lurking on and off for some time now, and have picked up some useful links from the community, and thought I'd finally contribute.

**pimpJ** · 09-09-2004, 06:36 PM

nice find

**purple_car** · 09-17-2004, 08:06 PM

Sweet find! Can you give us the pinout diagram? And how do you figure that stuff out anyway, I've always wanted to know?

**kickercivic1** · 09-17-2004, 09:05 PM

meeeeeee to need pins outs.

**toadster123** · 09-17-2004, 09:15 PM

nice find .. very inexpensive... any pictures of your setup??? diagrams?? the actual connector on the touchpad looks very small (like a thin ribbon cable was attached to it).. were u able to solder a cable or leads to it?

**Dominik** · 09-17-2004, 09:16 PM

D'oh, i did buyitnow (because it was so damn cheap!!), and forgot to check shipping to Australia... Here's to hoping its not too much more!!!

Mushin, could you email me the pinouts as well? dbloemhard at yahoo. com

Thanks!

**migel628** · 09-17-2004, 09:52 PM

I just grabbed 1 too, just in case I can find a use or pinout

**mushin** · 09-17-2004, 11:51 PM

Wow, you put up a link, there's like 1 reply for two weeks, and then all of a sudden everyone jump in

Like I said, I have figured out the pinouts, and you too can have them... for a price! MUAHAHAHAHA...

*ahem*

Looking at the bottom with the connector towards you and the chip away from you, the pinout looks like this:

vcc gnd n/a n/a data clock

(data & clock might be switched - I'm going from memory here, as I left my diagram at work - I'll double check it monday and notify you all if I'm wrong)
Edit: They are not switched, and are as presented above

The connector is a 12 pin connector, but as it turns out they're connected in pairs, so there's really only 6 connections. It makes soldering on to the backside (which is what I did, I have no idea what the connector type actually is) alot easier. Just tin a fine gauge wire, lay it between the shorted pins, and tap it with the iron.

I'll leave finding the corresponding pinout of the PS/2 port an exercise to the reader.

I can post a picture of it connected to a PS/2 plug if you like, but it's not very exciting. It's not incorporated into anything yet.

**mushin** · 09-18-2004, 12:02 AM

Originally Posted by purple_car

Sweet find! Can you give us the pinout diagram? And how do you figure that stuff out anyway, I've always wanted to know?

Magic

Actually, nothing fancy happened here. I figured out power and ground by looking at the traces on the PCB - a pile of stuff goes to ground so it's easy to identify, and power is a pretty easy guess since it goes to several locations unlike the other pins that go straight to a pin on the chip. Finding the data and clock was just a matter of trial and error, since I was pretty confident I couldn't damage anything by mixing them up (and if I did, I had 19 more sitting in a box

) I put plugs on all the wires so I can quickly try different combinations, and as it turned out, I got it on my third try.

I suppose it might have been easier to do it with a scope (the clock line should stick out like a sore thumb) but that just occured to me right now