FEETECH Standard Servo FS5103B-FB with Position Feedback

The FS5103B-FB is a specially modified version of FEETECH’s FS5103B standard-size analog servo that provides access to the feedback potentiometer through a fourth (green) wire, which makes it possible to directly measure the output angle. With this extra information, you can determine when the servo has reached its target position (or detect if something is interfering with its ability to get there). This feedback also enables more complex closed-loop control of the servo from your main controller.

Like the FS5103B, the FS5103B-FB works with standard RC servo pulses, providing a running angle of approximately 180° over a servo pulse range of 600 µs to 2400 µs. The feedback voltage varies linearly over this range by a couple of volts.

The servo signal, power, and ground are provided through a 3-wire servo cable that is terminated with a standard JR-style connector, which is Futaba-compatible. The feedback is accessible through a separate green wire that is terminated like Pololu's female premium jumper wires and works with standard 0.1" male header pins. These cables are approximately 12" (30 cm) long.

Servo and feedback connectors on the FEETECH servos with position feedback.

For more information about this servo, see the FS5013B datasheet (133k pdf) (please note that this is the datasheet for the standard FS5103B, so it does not include any information about the special feedback modification).

FEETECH Standard Servo FS5103B with included hardware (actual hardware might vary).

This servo is also compatible with Pololu's Mounting Bracket for Standard-Size Servos:

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

Comparison to the Power HD 3001HB servo

The FS5103B is a lower-cost alternative to the 3001HB from Power HD, which has nearly identical dimensions and similar performance. The two servos should be generally interchangeable for most applications. The picture below shows both the FS5103B and the 3001HB side by side:

People often buy this product together with:

Micro Maestro 6-Channel USB Servo Controller (Assembled)

Mounting Bracket for Standard-Size Servos

FEETECH FS90-FB Micro Servo with Position Feedback

Dimensions

General specifications

File downloads

• Datasheet for the FEETECH Standard Servo FS5103B (133k pdf)

  Note: while this datasheet lists the 6 V stall torque as 3.2 kg*cm, Feetech has since revised this to 3.8 kg*cm based on more recent measurements (this is also more in line with their listed 4.8 V stall torque of 3.0 kg*cm).