Copyright © Parallax Inc.
Parallax Continuous Rotation Servo (#900-00008)
v2.2 10/24/2011 Page 6 of 8
Voltage and RPM:
Maximum RPM will vary with input voltage; 50 RP M @ 5 V is typical. Using
regulated Vdd as the sup ply source will reduce fluctuations in RPM for a given pulse width that might
otherwise occur with unregulated battery supplies.
BASIC Stamp
®
Programming Examples
PBASIC has a PULSO UT command that sets the I/O
Pin to an output and sends a pulse of the specified
Duration. Since the servo needs this pulse refreshed every 20 ms for continuous operation, the PULSOUT
command is put in a coun ted FOR…NEXT loop to su stain continuous operation for the speci fied number
of cycles.
PULSOUT
Pin, Duration
Different BASIC Stamp m odules use different units for the P ULSOUT command's
Duration argument.
When adapting BS2 code to another BASIC Stamp model, you may need to make adjustments. The table
below lists the PULSOUT ranges for each BASIC Stamp microcontroller. See the BASIC Stamp Manual or
BASIC Stamp Editor Help for more information.
BASIC Stamp Model
1.3 ms
(Full speed clockwise)
1.5 ms
(Center, no rotation)
1.7 ms
(Full speed counterclockwise)
BS1
130 150
170
BS2, BS2e, BS2pe
650 750
850
BS2sx, BS2p, BS2px
1625 1875
2125
The example shown below for a BASIC Stamp 2 causes a servo connected to BASIC Stamp 1/0 pin 12 to
first rotate full-speed counterclockwise for about 3 seconds, hold still f or about 3 seconds, and then
rotate counterclockwise for about 3 seconds.
' RotateParallaxCrServo.bs2
' {$STAMP BS2}
' {$PBASIC 2.5}
counter VAR Word
servoPin PIN 12 ' change I/O pin for servo signal here
FOR counter = 1 TO 100 ' Rotate counterclockwise for ~3 seconds
PULSOUT servoPin, 850
PAUSE 20
NEXT