FEETECH Standard Servo FS5106B-FB with Position Feedback

This version of the FS5106B standard servo from FEETECH is specially modified to provide access to the feedback potentiometer through a fourth (green) wire, allowing you to directly measure the position of the output. This extra information enables more complex robotics applications, such as determining when the servo has reached its target, detecting when the output is blocked, or implementing your own higher-level closed-loop position control.

Key specs at 6 V: 0.16 sec/60°, 83 oz-in (6 kg-cm), 42 g.

Overview

The FS5106B-FB is a specially modified version of FEETECH’s FS5106B 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 FS5106B, the FS5106B-FB works with standard RC servo pulses, providing a running angle of approximately 180° over a servo pulse range of 700 µs to 2300 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 our 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 FS5016B datasheet (133k pdf) (please note that this is the datasheet for the standard FS5106B, so it does not include any information about the special feedback modification).

FEETECH Standard Servo FS5106B with included hardware (actual hardware might vary).

Bracket compatibility warning: This servo is currently not compatible with our Mounting Bracket for Standard-Size Servos. It is possible to permanently modify the bracket to work by cutting a notch out of it with a rotary tool or a pair of diagonal cutters, but do so at your own risk as it could damage the bracket.

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

FS5106B-FB vs FS5106R

Two versions of this servo are available. This product is the FS5106B-FB, which offers closed-loop position control over a limited range (approximately 180°). Alternatively, the FS5106R was designed specifically for open-loop speed control over an unlimited range. The FS5106B-FB and FS5106R have identical dimensions and use the same motor and gear reduction, but the FS5106R does not have the extra feedback wire since it does not have any feedback system.

Comparison to the Power HD 6001HB servo

The FS5106B is a lower-cost alternative to the 6001HB 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 FS5106B and the 6001HB side by side: