This sections gives some theoretical information on adding wheel encoders to your Ebot as well as some descriptions of implementations.
Using Encoders: This sections is a tutorial on using the information available from encoders
Adding Encoders: This shows different ways that you can add encoders to your Ebot
Hardware reader: Shows a hardware circuit that permits accurate encoder reading by Basic Stamp or equivalent processors with no interrupt capability.
Polling: Shows how a Basic Stamp or equivalent processor CAN read encoders without the hardware reader above (but with some loss of processing efficiency).