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SpringRC SM-S4303R Continuous Rotation Servo

Pololu item #: 1248 0 in stock
Brand: SpringRC

Price break Unit price (US$)
1 12.95
10 11.65
50 10.35


backorders allowed

The SM-S4303R is a standard-sized servo that has been built by SpringRC specifically for continuous rotation, making it an easy way to get your robot moving. It features two ball bearings on the output shaft for reduced friction, and it offers easy access to the rest-point adjustment potentiometer. This is the most popular continuous rotation servo we carry.

Key specs at 6 V: 54 RPM (no-load), 71 oz-in (5.1 kg-cm), 41 g

 Description Specs (9) Pictures (5) Resources (0) FAQs (1) On the blog (2) 

Overview

The SM-S4303R is a standard-sized servo that has been built by SpringRC specifically for continuous rotation. At 6 V, it has a maximum rotation speed of 54 RPM (no-load) and can produce up to 71 oz-in (5.1 kg-cm) of torque. It features two ball bearings on the output shaft for reduced friction, and it offers easy access to the rest-point adjustment potentiometer. The servo can be controlled using a direct connection to a single microcontroller I/O line without any additional electronics, which makes it a great actuator for beginner robotics projects.

The SM-S4303R continuous rotation servo converts standard RC servo position pulses into continuous rotation speed. The default rest point is 1.5 ms, but this can be adjusted by using a small screwdriver to turn the middle-point positioner. Pulse widths above the rest point result in counterclockwise rotation, with speed increasing as the pulse width increases; pulse widths below the rest point result in clockwise rotation, with speed increasing as the pulse width decreases.

The servo has an 11″ (270 mm) lead that is terminated with a JR-style connector and includes additional servo horns and mounting hardware. The following picture shows an example of the hardware that might be included (actual hardware could vary):

This robotics servo is compatible with our servo controllers and has a Futaba-compatible output shaft, which means it works with our servo wheels for standard servos (25T, 5.8 mm spline). This servo is also compatible with our Mounting Bracket for Standard-Size Servos:

If you are looking for a similar servo that is capable of limited-range position control as opposed to continuous rotation speed control, consider the Power HD standard servo 6001HB, which has comparable size, weight, speed, and torque.

Note: The spline on this servo is slightly bigger than on our other continuous rotation servos, so some servo horns and wheels might have a tight fit. If you find it difficult to push a compatible servo horn or wheel on by hand, please try the installation method shown in the video below. Similarly, the servo’s mounting tabs are a tight fit with our mounting bracket, so you might consider filing them or the mounting bracket down a little if you want to use them together.

Note that, as with most hobby servos, stalling or back-driving this servo can damage it.

Continuous rotation servo comparison

Continuous rotation servo size comparison. From left to right: SpringRC SM-S4303R, Power HD AR-3606HB, FEETECH FS5106R, Parallax Feedback 360°, Parallax (Futaba S148), and FEETECH FS90R.

6 V 4.8 V Weight (g) Size (mm) Digital? Feed­back? Price
Max speed
(RPM)
Stall torque
(oz·in)
Max speed
(RPM)
Stall torque
(oz·in)
SpringRC SM-S4303R 54 71 43 46 41  41.3 × 20.7 × 40.2  $12.95
PowerHD AR-3606HB 71 93 62 83 40  40.5 × 20.0 × 38.0  $14.95
FEETECH FS5106R 95 83 78 70 39  40.8 × 20.1 × 38.0  $13.95
Parallax Feedback 360° 140 35 41  40.0 × 20.0 × 37.2  yes yes $27.99
FEETECH FT90R 135 21 108 18 9  22.9 × 12.1 × 26.5  yes $7.95
FEETECH FS90R 130 21 100 18 9  23.2 × 12.5 × 22.0  $4.95

People often buy this product together with:

Micro Maestro 6-Channel USB Servo Controller (Assembled) Micro Maestro 6-Channel USB Servo Controller (Assembled)
0.100" (2.54 mm) Breakaway Male Header: 1×40-Pin, Straight, Double-Sided 0.100" (2.54 mm) Breakaway Male Header: 1×40-Pin, Straight, Double-Sided
4-AA Battery Holder 4-AA Battery Holder

Related Products

Pololu Wheel for Standard Servo Splines (25T, 5.8mm) - 70×8mm, Black, 2-Pack
Pololu Wheel for Standard Servo Splines (25T, 5.8mm) - 90×10mm, Black, 2-Pack
Mounting Bracket for Standard-Size Servos
Power HD SR8 Aluminum 25T Servo Horn

Related Categories

Continuous Rotation Servos
Pololu Wheels for Servos
RC Servo Controllers
Servo Cables
6.0 V NiMH Battery Packs
Voltage Regulators
Motors and Gearboxes
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