Julio Fajardo / Mbed 2 deprecated Nucleo_EMG_Galileo_Hand Featured

This is a simple EMG Controller for a bionic hand prosthesis

Dependencies:   mbed-dsp mbed NOKIA_5110

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Table of Contents

  1. Galileo Bionic Hand - ST Nucleo Example
  2. Galileo EMG Shield - 3 Channels for surface EMG
  3. Customizable Postures
  4. Serial Oscilloscope Feature
  5. Nolia 5110 LCD
  6. Information

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 implemented with the Galileo EMG Shield. 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

Galileo EMG Shield - 3 Channels for surface EMG

/media/uploads/julioefajardo/image1.jpg

Customizable Postures

You can customize the actions by modifying PWM values (microseconds) on FingerPosition function (values depends on the way that the hand was built it). The prosthesis has five fingers and a thumb rotation mechanism and five actuators in order to perform multiple types of grasping.

The servo motors have to be connected as shown below:

/media/uploads/julioefajardo/servos.png

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

Serial Oscilloscope Feature

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

Nolia 5110 LCD

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

Information

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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