Servo Modification for Continuous Rotation
The Trekker uses modified servos to drive the wheels. There are many benefits to modified servos, they are:
- Low Cost
- Have built in gear box and yield high torque
- Have built in speed controller
- Can easily be controlled with several OOPic Objects
A typical servo only has ~180 degrees of rotation. They need to be modified to allow continuous rotation, or you robots travel will be fairly limited. Detailed instructions are given in the Trekker manual, which you will receive electronic access to upon ordering any Trekker Product, or you can order a printed version of the manual. With all the Trekker Kits, you can order the servos pre- modified.
There are two ways to modify servos, (1) electronically, or (2) mechanically. When you order modified servos, we modify them mechanically. The basic steps are:
- Take the servo apart
- Remove the gears
- Center the potentiometer so a 150mSec pulse results in zero movement. We supply OOPic programs to do this from our Trekker downloads page, which you will gain access to when you purchase any Trekker Product.
- Remove the stop on the main gear that mechanically limits the servo to 180 degrees
- Reassemble the servo
- Test the servo
- Your servo is now set for continuous rotation!
Once the servo is modified, if you send a pulse a little off center (150mS) the servo will move slowly to reach its goal, but will never realize it since the potentiometer is decoupled. The result is the servo will continuously rotate slowly. Send a signal to move the servo far from the center, and the servo will rotate continuously fast.