PS/2 Mouse Optical Sensor

I’m working with older PS/2 mice for X Y tracking distance/ displacement for a small robot I’ve built. The PS/2 code is working tracking mouse movement well. For my purposes the drift over time ought to be okay. Time will tell.

I wanted to ask if anyone has run across or knows about successful approaches to lift the sensor off the surface to roughly 1/2 inch and preferably as much as 1 inch (1.25 - 2.5 cm).

Searching on the internet shows using a mouse has been attempted many times going way back to before 2008. The ones that seem to work place the mouse on the surface. Not what I want to do. This is an indoor smooth floor project initially. I did find an academic paper on the subject using a replacement lens between the sensor and floor. Not sure it was actually followed through on. Could not find any results for that project.

I’m looking for a place to purchase a small diameter lens with a given focal length, yet to be calculated. Or a technique that has accomplished the desired goal based on a mouse type sensor.

The attachments were borrowed from the web.

lens mounting.PNG

After researching the typical optical mouse sensor and the lens in particular the answer seems to be in the negative.

The depth of field is very small, ± 0.5 mm (± 0.019 inch). Anything much beyond this would not work. Aperture size would have to decrease to a small pin hole to increase the field of view into something that might work.

Mounting the sensor under a robot is impractical. Adjustment would be difficult and the robot will vibrate and move well outside the field of view.

If you think this conclusion is not correct please indicate why.

Depth of field is very small because there is a lens. You can change lens.
There are also some modules that use mice sensors, for example ADNS3080 modules, that are veri similar to Arduino cam boards. They have a different lens that you can focus retrieving the image instead of the directions.
They are named Optical Flow Sensor.

http://ardupilot.org/copter/docs/common-optical-flow-sensors-landingpage.html