Pololu Optical Encoder Pair Kit for Micro Metal Gearmotors, 5VPololu
Add quadrature encoders to your micro metal gearmotors (extended back shaft version required) with this kit consisting of two sensor boards, two 3-tooth encoder wheels, and two 5-tooth encoder wheels. The installed system does not exceed the 12 mm × 10 mm cross section of the motors and extends only 5 mm beyond the plastic motor end cap. The 3-tooth wheel provides 12 counts per revolution; using the 5-tooth wheel yields 20 counts per revolution. This version is intended for use at 5 V.
Note:This sensor system is intended for relatively advanced users comfortable with the physical encoder installation and with using the resulting signals. It only works with micro metal gearmotors that have extended back shafts.