Parallax Inc Propeller ActivityBot Wheel Encoder Kit

A pair of reflective opto-sensors designed to work with shaft-mounted slotted-discs providing rotational speed information. They can be used to provide basic odometry for a mobile robot.

Sharp GPA2025 modulated infrared sensors reduce interference from ambient light
Communication: Active-high (Vcc = reflection detected)
Power supply: +5Vdc @ 60mA
Operating temperature range: -10 to +60°C
Recommended disc/wheel: Parallax Small Robot Wheel & Tyre, RS 843-0897

The Propeller ActivityBot kit (RS 790-5227) contains this encoder kit and encoder wheels as standard.

2 x cables, 2 x 20kΩ resistors, 2 x mounting brackets, 2 x #4-40 machine screws

The Propeller™ 1 microprocessor chip makes it easy to rapidly develop embedded applications. Its eight 32-bit processors (COGs) can operate simultaneously, either independently or cooperatively, sharing common resources through a central hub. The developer has full control over how and when each cog is employed; there is no compiler-driven or operating system-driven splitting of tasks among multiple cogs. A shared system clock keeps each cog on the same time reference, allowing for true deterministic timing and synchronization. Two programming languages are available: the easy-to-learn high-level Spin, and Propeller Assembly which can execute at up to 160 MIPS (20 MIPS per COG).