Web Site: www.parallax.com Office: (916) 624-8333 Forums: forums.parallax.com Fax: (916) 624-8003 Sales: sales parallax.com Sales: (888) 512-1024 Technical: support parallax.com Tech Support: (888) 997-8267 Parallax Continuous Rotation Servo ( 900-00008) The Parallax Standard Servo is ideal for adding bidirectional continuous rotation to your robotics projects. Features Bidirectional continuous rotation 0 to 50 RPM, with a linear response to PWM for easy ramping Accepts four mounting screws Easy to interface with any Parallax microcontroller or PWM-capable device Very easy to control with the PULSOUT command in PBASIC or SX/B Weighs only 1.50 oz (42.5 g) 38 oz-in torque 6 V Key Specifications Power requirements: 4 to 6 VDC Maximum current draw 140 +/- 50 mA at 6 VDC when operating in no load conditions, 15 mA when in static state Communication: pulse-width modulation Dimensions: approx 2.2 x 0.8 x 1.6 in (5.58x 1.9 x 4.06 cm) excluding servo horn Operating temperature range: 14 to 122 F (-10 to +50 C) Quick-Start Circuit V Vservo Vdd White I/O Red Black Vss Microcontroller Continuous Rotation Servo GND V = microcontroller voltage supply Vservo = 4 to 6 VDC, regulated or battery I/O = PWM TTL or CMOS output signal, 3.3 to 5 V < Vservo + 0.2 V Copyright Parallax Inc. Parallax Continuous Rotation Servo ( 900-00008) v2.2 10/24/2011 Page 1 of 8 Device Information The Parallax continuous rotation servo relies on pulse width modulation to control the rotation speed and direction of the servo shaft. Before using the servo ina project, it is important to c alibrate the center position of the servo in order to define the pulse width value at which the servo holds still (see the section Calibration Cente the Servo on page 4). Specifications Pin Name Description Minimum Typical Maximum Units 1 (White) Signal Input TTL or CMOS 3.3 5.0 Vservo + 0.2 V 2 (Red) Vservo Power Supply 4.0 5.0 6.0* V 3 (Black) Vss Ground 0 V *See Board of Education Servo Header Connection Diagram. Power Precautions Do not use this servo with an unregulated wall-mount supply. Such powe supplies may deliver variable voltage far above the stated voltage. Do not power this servo through the BASIC Stamp Module s Vin pin, this can deliver voltages above the stated voltage. See the Board of Education Connection Diagram below for jumper settings. Servo current draw can spike while under peak load be sure your application s regulator is prepared to supply adequate current for all servos used in combination. Board of Education Servo Header Connection Diagram When connecting the servo to the Board of Education servo header, be sure the jumper is set t o Vdd (regulated 5 VDC for this board) as shown in the figure below. Failure to place the jumper at this setting can cause damage your servo (Note: see the Board of Education product documentation for instructions regarding earlier board revisions that do not have a servo header with a jumper.) 15 14 Vd d 13 12 Red Black X4 X5 Vin Using a Separate Power Supply on a HomeWork Board The BASIC Stamp HomeWork Board uses a 9 V battery for a power supply. A servo can drain a fresh 9 V battery in under 20 minutes Foll ow these directions to build two servo p orts on the breadboard, and power them with a separate battery pack. Hardware Required (1) BASIC Stamp HomeWork Board (serial 555-28158 or USB 555-28188) (1) Battery pack with tinned leads (Parallax 753-00001) (2) Parallax continuous rotation servos (2) 3-pin male-male headers (Parallax 451-00303) (4) Jumper wires (10-pack: Parallax 800-00016 (4) 1.5 V AA batteries Copyright Parallax Inc. Parallax Continuous Rotation Servo ( 900-00008) v2.2 10/24/2011 Page 2 of 8