This is a simple EMG Controller for a bionic hand prosthesis

Dependencies:   mbed-dsp mbed NOKIA_5110

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Galileo Bionic Hand - ST Nucleo Example

/media/uploads/julioefajardo/galileohand.png Low Cost and 3D printed: Galileo Bionic Hand

This is an example of a simple hybrid sEMG(surface Electromyography) activated controller for the Galileo Bionic Hand Prosthesis. The user has to select the desired posture by sending a special character through serial port (115200 baud rate) and then perform it through sEMG activation by detecting contraction on flexor muscles of the forearm. Contractions on forearm extensor muscles releases the posture and allows the return to the default or rest posture.

Special characters:

  • '1', for "Power Grip" selection
  • '2', for "Point" selection
  • '3', for "Pinch Grip" selection
  • '4', for "Lateral Grip" selection
  • '5' for "Tripod Grip" selection

/media/uploads/julioefajardo/serialinterface.png

Customazable Postures

You can customize the actions by modifying PWM values (microseconds) on finger position function (values depends on the way that the hand was built it).

Function Declaration and Usage Examples

include the mbed library with this snippet

void FingerPosition(float32_t thumb_us, float32_t index_us, float32_t middle_us, float32_t pinky_us, float32_t thumbrot_us);

FingerPosition(2400, 600, 600,2400,2400);   //Close
FingerPosition(2400,2400, 600,2400,2400);   //Point
FingerPosition(2400, 600,2400, 600,2400);   //Pinch
FingerPosition(2400, 600, 600,2400, 600);   //Lateral
FingerPosition(2400, 600, 600, 600,2400);   //Tripod
FingerPosition(1000,2400,2400, 600, 600);   //Open

Also, you can easily watch the data using a serial oscilloscope

  • Serial_Osciloscope(TRUE,RAW) to watch raw signals, FALSE deactivate this feature
  • Serial_Osciloscope(TRUE,RECTIFIED) to watch rectified signals, FALSE deactivate this feature
  • Serial_Osciloscope(TRUE,SMOOTH) to watch smooth signals, FALSE deactivate this feature

/media/uploads/julioefajardo/smooth_signal.png

Nokia 5110 display implementation for visual feedback will be add later, we have to modify libraries and fonts in order to improve the functionality. The main idea is to change of action by pressing a push button and change thresholds using a potentiometer.

/media/uploads/julioefajardo/lcd.png

Proper placement of disposable electrodes for two channels of surface EMG

/media/uploads/julioefajardo/electrodes.png

Galileo EMG Shield - 3 Channels for surface EMG

/media/uploads/julioefajardo/image1.jpg

Videos, bill of materials and tutorials to build the Galileo EMG Shield and the Galileo Bionic Hand will be posted soon, more information on:


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