Project: Optical tank mouse

[mrknight]

My tank mouse is quite unreliable. I've cleaned the rollers and the ball but sometimes the cursor still get stuck. It's quite annoying. I changed to another mouse which works better but still not perfect.

The other day I got an idea; Why not change the ball to an optical sensor? That way I can still use the original tank mouse but with the reliability of an optical mouse. I haven't done much research yet but it seems that if I am to buy a sensor I also need a matching LED and a lens. A better idea might be to buy a cheap mouse and use that sensor.

What are your opinions about this project? Have you done something similar? Is it going to be easy or too complicated? I'd like to hear your opinions.

[mrknight]

Nice to see your advice/ideas/concerns.

First, I never planned to  find a sensor that output Amiga compatible signals. I can program Atmel  AVR's so that's not a problem. I just have to learn how to read the  data from the sensor and then convert it to Amiga format. If fact, I  have a couple of spare ATtiny2313 with should be useable in a prototype. I probably could find a smaller one that is more production friendly.

I  bought a cheap mouse online and I will gut it and see if I can use the  sensor, lens and LED. What worries me a bit is the space inside the  mouse case. But with the ball out of the way there will hopefully be  enough space to mount the sensor/lens without having to damage the mouse  case.

A new PCB has to be designed. I guess I can use a protype  board to begin with. I haven't designed a PCB for many years but I  guess it's like riding a bike...

Yes, I could get a proper  optical mouse and a signal converter if I wanted, but I like the  challenge. I became and engineer because I like to build and develop  stuff. The end use is secondary.

[mrknight]

Not a bad idea.

The tank mouse also had inexpensive contacts for the mouse buttons.  After mine wore out, I tried to replace them with clicky micro switches.  It seems straightforward, but matching the heights and location of the actuating nub was difficult.  My repaired mouse never had a good 'feel'.

Did you change to another kind of switches? Then I can understand if you had problems. I changed both switches in my mouse and I changed it to the very same kind of switch and I never had any problems with the mouse since then.

[mrknight]

No, I didn't, couldn't find them.  You see the point, though.  The mechanical relationships for the buttons are surprisingly precise.

If I remember correctly, these are the switches I bought:
http://www.altronics.com.au/index.asp?area=item&id=S1120

It's in Australia so I guess you can't buy them but at least you can see the specs and name and all that.

Edit:
Found these on eBay. Could be the right one!
http://www.ebay.com.au/itm/261274322241

[mrknight]

An update: I got a $2 optical mouse from eBay and I had a look inside. The sensor is a MX8733 and it has a USB/PS/2 interface. Now I need to read up on the PS/2 and create some kind of MCU based testbed to evaluate it.