Optical Mice are an interesting beast. They have a small CCD video camera in them, and take many photos of the mousing surface, and do correlation analysis between shots to determine how the mouse has moved. The correlation function determines the most likely movement of the mouse – with some limit below which it assumes that the mouse has moved to somewhere with totally different image elements. Surprisingly the CCD sensor is usually only about 18×18 pixels. Given that video cameras are about 720 x 480 pixels, 18×18 is fairly course. Then again, of that is all that is needed why over engineer the device.

A student in The Netherlands has decided that this might be an interesting device to look at. He determined that he could read the image sensor using the serial port and take a lot of photos joining them together. Right now the mouse requires a hardware mod, and it appears that this means that the mouse is no longer workng. It remains to be seen if the USB mice can have new firmware uploaded to take photos whilst the mouse moves. Just think about things, how many times have documents been placed under a mouse. Imagine if a piece of spyware could scan the paper and send it to a non-trusted person over the net.

I have an interesting meeting this morning – an initial meeting for a new project. I might have to outsource part of this one, but it is still a fun one. It is over at Warringah Mall which is a pain to get to. Still, work is work.