FT90R Digital Micro Continuous Rotation Servo
The FT90R is a micro-sized digital servo that has been built by FEETECH specifically for continuous rotation. At 6 V, it has a maximum rotation speed of around 170 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 (FS90R-W) 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 is set precisely to 1.5 ms with a deadband width of ±20 µs. 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.
Note that, as with most hobby servos, stalling or back-driving this servo can damage it.
If you want to use this servo as an actuator for your miniature robot, you will need a wheel to go with it. Fortunately, we carry a 60×8 mm wheel (FS90R) specifically designed for use with this servo:
The wheel size is well matched to the servo’s speed and torque, allowing for a top speed of around 40 cm/s (1.3 ft/s) at 6 V.