SparkFun Forums

[etchin_uk]

I am currently undergoing a project to:

1. source a laptop touchpad (with buttons)
2. wire up to the ps/2 connection port
3. convert ps/2 connection into a wireless signal

i have just completed step 2 earlier on today, touchpad works on my desktop fine and now i am looking into converting the now ps/2 touchpad into a wireless unit. could i just source a wireless mouse and use the inards in conjuction with the ps/2 connection? anyone got any ideas on what kind of wireless i should use, RF, infrared, bluetooth??? is it actually possible for me to do this or am i wastin time?

any help would be appreciated

thanks

[etchin_uk]

anyone?

[SOI_Sentinel]

Patience, not everyone can answer directly

It's not a project I have tried to tackle. Most wireless mice these days are rather tightly integrated in a non-PS2 compatible manner for the RF/IR bridge, so you'd either have to program a microcontroller to translate to their protocol or translate your own protocol to PS2, I see it as a wash.

If you're comfortable with a microcontroller, building your own bridge would be ideal. You'll have to understand the PS2 protocol and see if it need any conversion to be easily transmitted. Bluetooth serial is rock solid and you would probably be able to make a PC recognize it as a serial mouse (check electrical specs first!) and also tend to have the longest working range. Nordic RF would also work fine, but you'll have a lot more work to get it working as you'd need your own RF stack. I believe the V200 mini RF optical mouse from Logitech used Nordic 2.4GHz chips. This MIGHT be hackable, but no one's tried to decode their protocol stack.

Possibly the simplest and most trouble free (but not cheapest!) would be touchpad->microcontroller->Bluetooth bridge->microcontroller->ps2 port. Sometimes having a fixed function serial port can have its advantages.

[silic0re]

i'm quite interested in how you found the pinouts for your touchpad module -- i've been wanting to interface touchpad's to a project of mine for some time, and have a number of old touchpads from laptops, but have had no success in finding any datasheets or anything to that effect that would describe the pinouts, or protocol (if they differ from ps2).


though i've never made a wired-PS/2 something into a wireless version, i just did some quick research that may help you out (from http://en.wikipedia.org/wiki/PS/2_connector ). It looks as though the PS/2 interface only uses one data pin, a clock, plus Vcc/ground. It looks as though the data rate is only 10-16 khz, which translates to a max of 16000 bits/sec = ~2000 bytes/sec.

If you wanted to be simple (simple is good! ), you could find a set of RF modules that are capable of doing approximately 2k/sec, whose pinouts contain simply a data in (or out) pin and a clock pin. You could try to just directly connect the lines of the touchpad to the transmitter module, and the receiver to the PS/2 port (of course, with proper buffering, voltage protection, testing, and all that jazz, to make sure you don't fry your motherboard or touchpad). Might be worth a try? You may even want to have an old machine like an IBM 386 or even an early pentium machine with PS/2 connectors on it, to make sure you don't fry anything important if something unexpected happens...

[SOI_Sentinel]

Like this?

http://instruct1.cit.cornell.edu/course ... chpad.html

for

http://www.goldmine-elec-products.com/p ... mber=G1283

[silic0re]

thanks!!!