Dextra - Open-source myoelectric hand prosthesis

Dextra is a printable human-sized robotic hand that is being developed as a part of a personal project aimed to develop an open-source and affordable robotic hand prosthesis. The key design points of Dextra are: adaptive grip, compact size, mechanical simplicity and ease of replication. The main element of Dextra is the finger module. The hand is modular: the four fingers are interchangeable, and the thumb is a variation of the finger module. The finger module comprises the printable mechanical finger, the actuator and an encoder. The compact actuator uses a DC micro gearmotor to rotate a spool that winds a fishing line, converting the rotational motion of the motor into a linear motion. The position of each finger module is controlled by a PID loop that uses the value provided by the magnetic encoder of the DC motor as the feedback signal. To be controlled by an amputee, Dextra uses a EMG interface that uses the user’s myoelectric signals as the high-level control input.”

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