Lesson 11 has been updated to be about standard servos instead of continuous rotation servos.
When the lessons for this website were first written we used continuous rotation servos to power a rolling robot. This robot is the integrating activity for the first semester of the class we teach.
So, naturally Lesson 11, Servos and Helper Methods was written to teach how continuous rotation servos work, and how to control them through an Arduino sketch.
Later, to improve the performance of the robot and to expand the class content these servos were replaced by brushed motors. With this came the opportunity to add content about the H-bridge and the management of electro-magnetic noise.
This year in our class we have added aircraft in the form of a simple airplane based on the design favored by Brookyn Standard ServoAerodrome. and the quadcopter. The airplane is controlled by a pair of standard servos, each connected to an aileron. Moved together they control the craft's pitch while independent movement controls roll.
The problem is, the programming of standard servos is similar to that of continuous rotation servos, but not identical. For this reason we have re-written Lesson 11. In it we have kept the content about helper methods but changed just about everything else.
The old Lesson 11 will reappear soon as "retired".