2009:Mouse details

USB Ball Mouse -

power from PC to mouse is +5vdc.

Pulse Rate = 5 micro second (top two lines)

Long Pulse--->Long Pulse = 200 micro seconds (bottom length)

Image:Pulse lengths

1/200uS = 5000cycles/sec - - - this is the maximum detectable rate

sensor wheel = 60 counts per revolution (CPR)

Calculate maximum detectable ground speed:

     5000cps/60CPR = 83.3 max revolutions per second (rps)

     diameter of mouse ball = 0.875"

     circumference of mouse ball  = Pi * d = 2.7489" circumference

                 measured counts per foot on current mouse on robot - 1210, or ~100 counts per inch

     83.3rps X 0.875" = 72.9 inches per second (ips)

     72.9ips/12 = 6.07 feet per second (fps) = maximum detectable linear ground speed

     6.07fps = 4.1 miles per hour (just in case you were curious)

It appears the phototransistor may be an "EverLight" Device...  Check out something "similar".

PS/2 Ball Mouse -

USB Optical Mouse -