Project Title & GitHub Link

EMG Powered Gripper

Technologies

Microcontrollers, C

Project

For this project, my group and I created a mechanical gripper powered by muscle signals to mirror the opening and closing of a user's hand.

Creating the Gripper

Our device was built around the micro:bit board which uses a NRF52833 microcontroller. It takes two analog inputs: an EMG signal from the user’s arm, which determines whether the person is flexing, and a force sensitive resistor (FSR) on the inside pad of the gripper, which signals when the grippers are holding an object. It controls a servo motor driver through I2C, which in turn controls the servo motor attached to the gripper via PWM signals.

Device Logic

When the user flexes and the signal from the EMG goes high, a signal is sent to the servo to close the grippers. If the FSR ever goes high during this action, this overpowers the EMG signal and tells the grippers to stop closing. Finally, if there is no EMG signal, the grippers will open. When put all together, this creates a smooth opening and closing motion that mimics the user’s hand.

Description

Sensors and actuators for the gripper

Using the Gripper as an End Effector

We collaborated with another team of students to merge our final projects. This group created a 2DOF arm that is powered by an IMU. The IMU is worn on the wrist, and when the user tilts their arm, the mechanical arm will mimic the motion. We attached our gripper as an end effector to their arm. Then, the user can wear both the IMU band and the muscle sensor for even more control, even being able to complete simple pick-and-place tasks with the arm.