27404 Parallax Inc, 27404 Datasheet - Page 149

• 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

Figure 4-2 The Servo Control Loop
The
will run. Every time through the loop takes about 24.6 ms, so 41 times through the 24.6
ms loop takes about 41 × 0.0246 ≈ 1 second.
EndValue
Half a second of servo rotation would be an
The graph in Figure 4-3 shows how you can use the
argument to control the servo's speed and direction. Recall that the
argument has units of 2 µs. A pulse width of 1300 µs, equal to a
650, is full speed clockwise.
counterclockwise. A
FOR...NEXT
Sensors will change the effective PAUSE time. When the effective PAUSE time has
changed, it will take some experimenting to re-tune the FOR...NEXT loop EndValues to
get the servo rotation times you want.
The servos have to turn opposite directions to make the SumoBot roll forward. If this
seems counterintuitive, look at the SumoBot's right side. That wheel has to turn clockwise
to make the SumoBot roll forward. Now look at the SumoBot's left side. That wheel has to
turn counterclockwise to make the SumoBot roll forward.
Applying the same train of though for rolling backward, the right servo has to turn
counterclockwise, and the left servo has to turn clockwise. By rotating both servos the same
direction, you can either make the SumoBot rotate right or left. To make the SumoBot rotate
left, both wheels must turn clockwise. To make the SumoBot rotate right, both wheels must
turn counterclockwise.
argument to 82 would make the servos run for twice the time, about 2 seconds.
loop's
Duration
EndValue
of 750 (1500 µs) yields no rotation.
is the number of 1/41 second increments the servo
A
Duration
EndValue
of 850 (1700 µs) is full speed
Increasing the
of 20, and so on.
PULSOUT
PULSOUT Duration
command's
FOR...NEXT
PULSOUT Duration
Duration
loop's
of