[Coco] A way to use a serial mouse? (was: Mouse (Bill))

[Andrew]

I read this message, and no, there isn't a way to simply "re-wire" a 
serial mouse to hook up to the coco, short of via an RS-232 pak and some 
OS-9 drivers (and even then, IIRC there were issues?)...

But...

What about this (and maybe I should try it out, although I don't have 
the time, I have all the hardware - hmm): Connect a serial/ps-2 mouse up 
to an Arduino (or any other favorite microcontroller that has the right 
ports, etc), then hook the Arduino up to the joystick port. The Arduino 
would then have code to read the serial data then convert it using its 
internal commands into the voltage level outputs on other pins which 
feed into the CoCo.

It would be real simple then to do some other funky things, such as 
"mouse macros", as well as create a form of hi-res interface (if you 
connected to the cassette port). I could also see this thing interfaced 
to the bit-banger serial port...

This should be VERY simple to build - the difficult part would be the 
code (maybe). On an Arduino, you could even (in theory) interface to a 
USB mouse. It has enough commands for the serial input (though you might 
need a level shifter?). Hmm - I am also seeing code on the site to read 
a PS/2 keyboard (maybe a way to hook a PS/2 keyboard to the CoCo?):

http://arduino.cc/en/Reference/Libraries

But for PS/2 or RS-232 mouse - you might be on your own writing code, 
but I bet somebody else has already done it. I could see even 
interfacing something like a Playstation joypad to the CoCo with 
something like this (although it would probably be single player only - 
you would need to use both joystick ports likely unless you did some 
form of multiplexing).

Hmm - here's some PS/2 mouse stuff:

http://www.arduino.cc/playground/ComponentLib/Ps2mouse

Ok - for the voltage output you just use PWM commands (and you might 
need a cap for smoothing - not sure how the coco would react):

http://principialabs.com/arduino-pulse-width-modulation/

Hmm - actually, this project is now looking pretty simple...I wish I had 
fewer projects, more time, and a host of other things...

-- Andrew L. Ayers, Glendale, Arizona