27404 Parallax Inc, 27404 Datasheet - Page 20

• Manufacturer Part Number: 27404
• Description: COMPETITION RING FOR SUMOBOT
• Manufacturer: Parallax Inc

Specifications of 27404

• Accessory Type: Hobby and Education
• Product: Microcontroller Accessories
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• For Use With/related Products: SumoBot®
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Contains lead / RoHS non-compliant

ACTIVITY #2: PREVENTING SERVO SLOWDOWN
A SumoBot that executes certain maneuvers more quickly will have an edge over a
slower opponent. One of the things that can slow your SumoBot down is trying to read
too many sensors between servo pulses. This activity examines how much time your
SumoBot can actually take between servo pulses before it starts to slow down. Later
activities will introduce ways to reduce the time it takes to read certain sensors.
Parts Required
(2) Parallax SumoBot robots
(8) New 1.5 volt AA batteries - same brand and type
Top Speed vs. Low Time
The high time of both pulse trains in Figure 1-6 control servo speed and direction.
Because both pulse trains have high times of 1.7 ms, either pulse train will make a servo
turn full speed counterclockwise. The problem is that full speed for a servo with 40 ms
between pulses isn't quite as fast as the full speed for a servo with 20 ms between pulses.
For example, the servo might turn 53 RPM with 20 ms pauses between pulses, but only
47 RPM with 40 ms.
A notebook for your observations - keep notes on the various results you observe for
developing wrestling strategies.
Maximizing speed and strength
In robotics clubs, competitors often rely on new servo gear sets or DC motors along with
hobby RC batteries to optimize their competition robot for speed and brute force.