FEETECH Ultra-High-Torque, High-Voltage Digital Giant Servo FT5335M-FB with Position Feedback
This version of the 1/4-scale FT5335M ultra-high-torque, high-voltage digital giant 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 7.4 V: 0.18 sec/60°, 550 oz-in (40 kg-cm), 180 g.
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The FT5335M-FB is a specially modified version of FEETECH’s FT5335M ultra-high-torque, high-voltage digital giant 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.
The FT5335M-FB is a giant-scale (also called 1/4-scale or mega-scale) digital servo from FEETECH that can deliver more than twice the torque of our strongest standard-size servo, offering up to 550 oz-in at 7.4V or 480 oz-in at 6 V (if you need even more torque than this, check out the much larger Torxis monster servos, and if you need a lot of torque in a smaller size or with more speed, consider the FT5121M and FT5313M high-torque digital servos). The picture on the right shows how the giant-size FT5335M compares to a standard-size servo.
Like the FT5335M, the FT5335M-FB works with standard RC servo pulses, providing a running angle of approximately 120° over a servo pulse range of 900 µs to 2100 µs. The feedback voltage varies linearly over this range by a couple of volts. Many hobby servos can be operated beyond their standard ranges by using a wider pulse range, but please note that in our tests, we were not able to expand the range of the FT5335M significantly beyond 120° (the servo did not respond to pulses below around 900 µs or above around 2100 µs).
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. Unlike typical hobby servos, the FT5335M has an operating voltage range of 6 V to 7.4 V.
Note: This servo can draw bursts of current in excess of 9 A at 7.4 V, so please make sure you have an appropriate power supply. For comparison, a typical standard-size servo might draw around an amp when straining.
The included servo horns are plastic, but we also carry a compatible metal horn (sold separately) that can be used as a more robust lever arm in ultra-high-torque applications:
The picture below shows the all-metal gear train that helps the servo deliver such high torque:
For more information about this servo, see the FT5335M datasheet (111k pdf) (please note that this is the datasheet for the standard FT5335M, so it does not include any information about the special feedback modification).
Note that, as with most hobby servos, stalling or back-driving this servo can damage it.
Comparison to the Power HD 1235MG servo
This servo is a lower-cost alternative to the 1235MG 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 FT5335M and the 1235MG side by side:
The servo output splines have the same number of teeth, but the diameter of the one on the FT5335M is approximately 0.2 mm bigger. This means that the servo horns included with the FT5335M can be used with the 1235MG, but not the other way around.