900-00005

Web Site: www.parallax.com Forums: forums.parallax.com Sales: sales@parallax.com Technical: support@parallax.com Office: (916) 624-8333 Fax: (916) 624-8003 Sales: (888) 512-1024 Tech Support: (888) 997-8267 Parallax Standard Servo (#900-00005) The Parallax Standard Servo provides 180° range of motion and position control to your project. Great for animatronics and robotics applications. Features        Holds any position between 0 and 180 degrees 38 oz-in torque at 6 VDC Accepts four mounting screws Easy to interface with any Parallax microcontroller or PWM-capable device Simple to control with the PULSOUT command in PBASIC High-precision gear made of POM (polyacetal) resin makes for smooth operation with no backlash Weighs only 1.55 oz (44 g) Key Specifications     Power requirements: 4 to 6 VDC*; Maximum current draw is 140 +/- 50 mA at 6 VDC when operating in no load conditions, 15 mA when in static state Communication: Pulse-width modulation, 0.75–2.25 ms high pulse, 20 ms intervals Dimensions approx 2.2 x 0.8 x 1.6 in (5.58 x 1.9 x 40.6 cm) excluding servo horn Operating temperature range: 14 to 122 °F (-10 to +50 °C) *Power Requirement Notes The manufacturer specifies 4-6 VDC for this servo. However, we find that this servo is tolerant of a 9 V battery for very brief periods of time when there is no load, as used in some activities in the Stamps in Class series of tutorials. (Slight jittering may be observed when batteries are fresh; this does not cause damage). Do not use this servo with an unregulated wall-mount supply, or a regulated wall mount supply exceeding 6 VDC. Servo current draw can spike while under load. Be sure that your application's power supply and voltage regulator is prepared to supply adequate current for all servos used. Do not try to power this servo directly from a BASIC Stamp module's or any microcontroller’s Vdd or Vin pins; do not connect the servo's Vss line directly to the BASIC Stamp module's or any microcontroller’s Vss pin. Copyright © Parallax Inc. Parallax Standard Servo (#900-00005) v2.2 10/24/2011 Page 1 of 5 Quick-Start Circuit Vµ Vservo Vµ = microcontroller voltage supply Vdd Vservo = 4 to 6 VDC, regulated or battery White I/O I/O = PWM TTL or CMOS output signal from microcontroller: 3.3 to 5 V, not to exceed Vservo + 0.2 V Red Black Vss Microcontroller Standard Servo GND Specifications Pin Name Description Minimum Typical Maximum Units 1 (White) 2 (Red) 3 (Black) Signal Vservo Vss Input; TTL or CMOS Power Supply Ground 3.3 4.0 5.0 5.0 0 Vservo + 0.2 6.0 V V V Power Precautions     Do not use this servo with an unregulated wall-mount supply. Such power supplies may deliver variable voltage far above the stated voltage. Do not power this servo through the BASIC Stamp Module's Vdd pin. 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. Some Stamps in Class tutorials, such as What's a Microcontroller? instruct the user to briefly power these servos with a 9 V battery when using a HomeWork Board and no load; this does not cause damage. Board of Education Jumper Connection When connecting the servo to the Board of Education Rev C’s servo header, be sure the jumper is set to 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. 15 14 Vdd 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! Follow these directions to build two servo ports 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 standard servos (#900-00005) (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 Standard Servo (#900-00005) v2.2 10/24/2011 Page 2 of 5 √ √ √ √ √ Disconnect the 9 V battery from the board, and do not put the AA batteries in their holder yet. Build the servo ports shown by the schematic and wiring diagram below. Double-check to make sure the black wire with the white stripe is connected to Vbp, the solid black wire is connected to Vss, and that all the connections for P13, Vbp, Vss, Vbp (another one), and P12 all exactly match the wiring diagram. Connect the servo plugs to the male headers on the right side of the wiring diagram. Connect the 9 V battery, and insert the AA batteries into their holder. Vbp Vbp stands for Voltage battery pack. White Red Black P13 It refers to the 6 VDC supplied by the four 1.5 V batteries. This is brought directly to the breadboard to power the servos. BASIC Stamp is still powered by the 9 V battery. Vss Vbp White Red Black P12 Vss Battery pack solid black wire = ground Battery pack black wire with white stripe = Vbp (916) 624-8333 www.parallaxinc.com www.stampsinclass.com Vdd Vin (916) 624-8333 www.parallaxinc.com www.stampsinclass.com Rev B Vdd Vss Port connections Vss X3 X3 P15 P14 P13 P12 P11 P10 P9 P8 Vin Rev B      P13 Vbp Vss Vbp P12 P15 P14 P13 P12 P11 P10 P9 P8      White Red Black Red White Servo connections by wire color HomeWork Board with servo ports built on the breadboard, with a separate battery pack power supply for the servos. Copyright © Parallax Inc. Parallax Standard Servo (#900-00005) v2.2 10/24/2011 Page 3 of 5 Communication Protocol The Parallax Standard Servo is controlled through pulse width modulation, where the position of the servo shaft is dependent on the duration of the pulse. In order to hold its position, the servo needs to receive a pulse every 20 ms. Below is a sample timing diagram for the center position of the Parallax Standard Servo. BASIC Stamp 2 Programming Example PBASIC has a PULSOUT command that sets the I/O pin to an output and sends a pulse of a specified duration. PULSOUT Pin, Duration The example shown below for a BASIC Stamp 2 causes a servo connected to BASIC Stamp I/0 pin 12 to turn to and hold its center position for approximately 5 seconds. ' CenterStdServo.bs2 ' {$STAMP BS2} ' {$PBASIC 2.5} counter VAR Word FOR counter = 1 TO 220 PULSOUT 12, 750 PAUSE 20 NEXT Servo I/O pin Number of 44ths of a second to hold the position, for the BS2 FOR counter = 1 TO 220 PULSOUT 12, 750 PAUSE 20 NEXT Position to hold, in 2 µs units for the BS2 Required 20 ms between each pulse Copyright © Parallax Inc. Parallax Standard Servo (#900-00005) v2.2 10/24/2011 Page 4 of 5 For detailed explanations using the BASIC Stamp 2, see What's a Microcontroller? Chapter 4, available for free download from www.parallax.com/go/WAM. Different BASIC Stamp modules use different units for the PULSOUT command's Duration argument. When adapting BS2 code to another BASIC Stamp model, you may need to make adjustments. See the article “Adapt BS2 Code to Other Models” in the PBASIC Language section of the BASIC Stamp Editor Help. The table below lists the PULSOUT ranges for each BASIC Stamp model. BASIC Stamp Module 0.75 ms 1.5 ms (center) 2.25 ms BS1 75 150 225 BS2, BS2e, BS2pe 375 750 1125 BS2sx, BS2px, BS2p24/40 938 1875 2813 Propeller P8X32A Programming Example Servo control with the Propeller chip is simplified by using a cog’s counter modules. The code below causes a servo connected to I/O pin P0 to turn to and hold the 90° position. For more information about counter modules and PWM with the Propeller, see Chapter 7 in the Propeller Education Kit Labs: Fundamentals text, which is included as a PDF in the Propeller Tool IDE Help. {{ CenterParallaxServo.spin For centering Parallax Continuous Rotation Servo or holding Parallax Standard Servo at 90° position. Sends a 1.5 ms pulse approx every 20 ms }} CON _clkmode = xtal1 + pll16x _xinfreq = 5_000_000 servoPin = 0 ' System clock → 80 MHz ' Using 5 MHz external crystal oscillator ' Servo signal to this I/O pin-change if needed PUB CenterServo | tInc, tc, tHa, t ctra[30..26] := %00100 ctra[8..0] := servoPin ' Configure Counter A to NCO frqa := 1 dira[servoPin]~~ ' Set up cycle and high times tInc := clkfreq/1_000_000 tC := tInc * 21_500 tHa := tInc * 1500 t := cnt ' Mark counter time repeat phsa := -tHa t += tC waitcnt(t) ' ' ' ' Repeat PWM signal Set up the pulse Calculate next cycle repeat Wait for next cycle Revision History Version 2.1: corrected specifications for torque. Updated PULSOUT range table. Added Using a Separate Power Supply on a HomeWork Board section beginning on page 2. Copyright © Parallax Inc. Parallax Standard Servo (#900-00005) v2.2 10/24/2011 Page 5 of 5 Mouser Electronics Authorized Distributor Click to View Pricing, Inventory, Delivery & Lifecycle Information: Parallax: 900-00005-RT 900-00005