Optical mouse with PIC

Gerhard · Joined: 30 Aug 2007 Posts: 144 Location: South Africa

Hi. I searched on the site to see if someone has done this before but i cant find anything. I want to use a normal optical mouse found in PC's and strip it to make that a distance moved sensor. Has anybody done this type of thing before using CCS and PIC? If posible can someone point me in the right direction such as type of protocal used and some reference sites to have a look at.
Thanks

RLScott · Joined: 10 Jul 2007 Posts: 465

Gerhard · Joined: 30 Aug 2007 Posts: 144 Location: South Africa

The idea is to use as much of the mouse as possible and if it is like the old wheel mice that had the bal just use the X and Y coordinates to detect if an object has moved and how far it has moved refered to the ground or some other object. Basicaly the same as a pc does it but just manipulate the data sent to my aplication. I would use it to measure how far a small remote controlled car has moved in the X and Y direction. If the mouse uses something like rs 232 or i2c i would like to find out what the packet is that is sent and how it would be possible in CCS to read and decode that data. I would preferably use a USB type of mouse but if that is not possible i would switch to PS2.

Thanks for the reply

RLScott · Joined: 10 Jul 2007 Posts: 465

I assume your remote control car is not going to go faster than the upper limit of the mouse decode speed. The mice have been designed for manual pointing use and do not have the capability to read speeds that are much faster than that.

The logic of the mouse is all encapsulated in the chip inside it. If you want to interace to it using USB, then you will have to make your PIC play the role of a USB host, which is 100 times harder than playing the role of a PS-2 host.
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Gerhard · Joined: 30 Aug 2007 Posts: 144 Location: South Africa

Thanks.
The project is just to see if something like this could be possible so even if the speed is the problem it is just to check if it can be done.

I found a website that explains how the ps-2 protocol works, but I see that the clock gets generated by the mice so the pic will need to look at the clock generated then use that for the coms. Sounds almost like I2C. Where would be a good starting point on the project or does anyone have some advice on how I would be able to do this.

Here is a link to that site.
http://www.computer-engineering.org/ps2protocol/

Thanks in advance

ckielstra · Joined: 18 Mar 2004 Posts: 3680 Location: The Netherlands

Did you have a look at the CCS provided example ex_mouse.c? This example is the other way around, it has the PIC simulate a mouse, but should give some useful pointers.

SherpaDoug · Joined: 07 Sep 2003 Posts: 1640 Location: Cape Cod Mass USA

I played with this a few years ago, mostly from the mechanical point of view and I never got the software to work. But I did find I could use lenses to increase the stand-off distance and top speed at the cost of resolution. It requires a lot of light but I had a video camera that needed strong light anyway.
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