Feetech STS3215 Servo 7.4V

The Feetech STS3215 is a 7.4V smart serial bus servo with a 12-bit magnetic encoder, metal gears and a dual-axis plastic case. Instead of a PWM signal, it is driven over a half-duplex TTL serial bus: every servo has its own ID, so many servos can be daisy-chained on one cable and each one reports its position, speed, load, voltage, current and temperature back to the controller.

Choose your gear ratio

All three versions run at 7.4V and share the same body, connector and bus protocol, so they can be mixed on one bus. Pick the ratio when you order.

Gear ratio	Stall torque	Rated torque	No-load speed	Stall current
1:345 (C001)	19.5 kg·cm	5 kg·cm	0.192 s/60° (52 RPM)	2.5 A
1:191 (C044)	27.4 kg·cm	9 kg·cm	0.116 s/60° (86 RPM)	3.8 A
1:147 (C046)	14.4 kg·cm	4.8 kg·cm	0.094 s/60° (106 RPM)	3.3 A

• 1:345 (C001) has the highest reduction, so it is slower and steadier, with strong holding torque. It is the standard choice for the joints of the SO-ARM100 / SO-ARM101 follower arm.
• 1:191 (C044) is the strongest of the three, with a good balance of torque and speed. Used on the heavier-loaded joints of the SO-ARM101 leader arm.
• 1:147 (C046) is the fastest, with the lowest reduction. Suited to joints that need quick movement more than torque, such as the wrist and gripper of the SO-ARM101 leader arm.

Specifications (all ratios)

Input voltage	7.4V nominal
Rotation	360° — 4096 steps (≈0.088° per step)
Encoder	12-bit magnetic
Gears	Metal
Communication	Half-duplex TTL serial bus, 38,400 bps – 1 Mbps
Servo IDs	0 – 253
Feedback	Position, speed, load, voltage, current, temperature
Size	45.2 × 24.7 × 35 mm
Weight	55 g
Operating temperature	−20 to 60 °C

In the box

• 1 × STS3215 servo in your chosen gear ratio
• Servo horns and mounting screws
• 3-pin connection cable