28125 Parallax Inc, 28125 Datasheet - Page 127

• Manufacturer Part Number: 28125
• Description: TEXT ROBOTICS
• Manufacturer: Parallax Inc

Specifications of 28125

• Title: Robotics with the Boe-Bot
• Product: Microcontroller Accessories
• Lead Free Status / RoHS Status: Not applicable / Not applicable

When the servo is done turning, you will be prompted to enter another value.
Try measuring the wheel's rotational speed in RPM (revolutions per minute) for a range
of pulse widths between 650 and 850. Here's how:
' Robotics with the Boe-Bot - TestServoSpeed.bs2
' Enter pulse width, then count revolutions of the wheel.
' The wheel will run for 6 seconds
' Multiply by 10 to get revolutions per minute (RPM).
'{$STAMP BS2}
'{$PBASIC 2.5}
counter
pulseWidth
pulseWidthComp VAR
FREQOUT 4, 2000, 3000
DO
DEBUG "Enter pulse width: "
DEBUGIN DEC pulseWidth
pulseWidthComp = 1500 - pulseWidth
√
√
√
√
√
√
Type 850 and then press the Enter key.
Verify that the servo turns full speed counterclockwise.
Place a mark on the wheel so that you can see how far it turns in 6 seconds.
Use the Debug Terminal to test how far the wheel turns for each of these pulse
widths: 650, 660, 670, 680, 690, 700, 700, 710, 720, 730, 740, 750, 760, 770,
780, 790, 800, 810, 820, 830, 840, 850
For each pulse width, multiply the number of turns by 10 to get the RPM. For
example, if the wheel makes 3.65 full turns, it was rotating at 36.5 RPM.
Explain in your own words how you can use pulse width to control Continuous
Rotation servo speed.
VAR
VAR
Word
Word
Word
' Signal program start/reset.