Chapter 3: Assemble and Test Your Boe-Bot
· Page 113
When the servo is done turning, you will be prompted to enter another value.
√
Type 850 and then press the
Enter
key.
√
Verify that the servo turns full speed counterclockwise.
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:
√
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.
' 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 VAR Word
pulseWidth VAR Word
pulseWidthComp VAR Word
FREQOUT 4, 2000, 3000 ' Signal program start/reset.
DO
DEBUG "Enter pulse width: "
DEBUGIN DEC pulseWidth
pulseWidthComp = 1500 - pulseWidth
