FEETECH FT90R Digital Micro Continuous Rotation Servo

The FT90R is a micro-sized digital servo that has been built by FEETECH (formerly known as Fitec) specifically for continuous rotation. At 6 V, it has a maximum rotation speed of around 135 RPM (no-load) and can produce up to 21 oz-in (1.5 kg-cm) of torque. 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 miniature actuator for beginner robotics projects; just throw on a pair of wheels and your robot is ready to roll!

The FT90R continuous rotation servo converts standard RC servo position pulses into continuous rotation speed. The rest point (sometimes called neutral position) is set to 1.5 ms. 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 a 10" (250 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, which is a digital version of the FEETECH FS90 continuous rotation servo, is compatible with Pololu's servo controllers. 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 FS90, which has identical dimensions, or the Power HD micro servo HD-1900A, which has almost the same weight, speed, and torque as the FS90.

You can find more information about this servo in its datasheet (110k pdf).

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

Wheels

If you want to use this servo as an actuator for your miniature robot, you will need a wheel to go with it. Fortunately, Pololu carry compatible servo wheels for micro servos (21T, 4.8 mm spline):

54	71	43	46	41	41.3 × 20.7 × 40.2	CCW?CW
140	35	–	–	41	40.0 × 20.0 × 37.2	CW?CCW
130	21	100	18	9	22.5 × 12.1 × 23.4	CW?CCW

People often buy this product together with:

Micro Maestro 6-Channel USB Servo Controller (Assembled)

FEETECH FS90R Micro Continuous Rotation Servo

Parallax Feedback 360° High-Speed Servo

Dimensions

General specifications

Notes:

1

Stalling should generally be avoided as it can damage the motor and gears.

File downloads

• Datasheet for the FEETECH FT90R Digital Micro Continuous Rotation Servo (110k pdf)

  Note: the speeds listed in this datasheet are not correct; the actual max speed at 6V is approximately 135 RPM. Also, this datasheet incorrectly specifies that the output spline is 20T when it really is 21T.