I know this is off-topic but I feel compelled to reply…
• Red LEDs are the cheapest to manufacture. • Most optical mouse CCD array sensors have peak sensitivity in the near-infrared to red wavelength range. • Red LEDs will operate on the lowest voltage of any visible light producing LED. • Red LEDs consume less power than any other colour LEDs.
I’ve seen optical mice that use blue LEDs instead of the normal red, and laser mice usually use infrared lasers so you can’t see the beam at all. Pink LEDs do exist, so although they wouldn’t be as efficient you could definitely have a pink LED optical mouse. You could even make your own by swapping the LED out of a normal optical mouse for a pink one.
You would have to update the You would have to update the software to act differently for different levels of light that the sensor is reading. It isnt just as simple as changing a LED.
Actually many optical mouse chips can calibrate themselves automatically to different light conditions, although you normally wouldn’t be able to change the mouse’s behaviour via software anyway. In the case of a UV LED, the light coming from the LED is waaay down towards the insensitive end of the sensor’s detection range, so it would be very hard for the optical chip to produce an image.
This graph is taken from the datasheet for a moderately modern optical mouse sensor chip which I already had. UV LEDs operate at roughly 380-405nm wavelengths, and as you can see from the graph this sensor is about 3 times less sensitive to that than it is to a perfectly chosen LED.
If you have an optical mouse with a good, auto-adjusting chip, it actually is just as simple as changing the LED. If you use an LED that the sensor is less sensitive to you might need a brighter LED to compensate. Also, depending on the original circuit, you might need to make some slight wiring changes to accomodate the different LED forward voltage.
