RH6D

Child-size proportions set the RH6D from Seed Robotics in Lisbon apart: it is built for humanoids up to 1.2 m tall and for smaller robot arms. Six smart actuators, each with a 32-bit ARM Cortex-M core and a co-processor, drive fifteen degrees of freedom through under-actuation; the fingers have three segments and the thumb is opposable.

The hand weighs just 305 g and holds 750 g in a vertical pull or 450 g freely in space. Every actuator reports position, speed, current and temperature, a time-of-flight distance sensor sits in the palm, and capacitive pads or FTS tactile sensors can be added as options.

It accepts 9 to 24 V and talks RS-485 or TTL with the Dynamixel protocol in versions 1.0 and 2.0, plus USB and optional Bluetooth; ROS and PyPot are supported. Pricing from distributor Knox Labs is on request, and the maker does not state the hand's length.

The adult-size RH8D is the larger sibling with eight actuators, while a small humanoid like ROBOTIS OP3 represents the scale this hand is made for.