Muscle Sensor MYO v1.5:
connection to Arduino

In this article, we will show the process of connecting the MYO v1.5 sensor to Arduino.
It is a briefly overview regarding the connection MYO v1.5 to Arduino. The more details about the sensor you can find in the datasheet here and we strongly recommend you to read it.

In that particular overview we show an example of connection EMG sensor MYO v1.5 to Arduino Uno. When connecting MYO v1.5 to another microcontroller of the Arduino family, the location of the SPI pins may differ - please, check pinout of your board carefully.

The sensor has 6 outputs:

GND — ground;
VCC — positive power contact;
OUT – output;
SCK — SPI data line for transmitting a clock signal for slaves;
MOSI — SPI data line, used to transmit data from the master to the slave;
CS — SPI data line, chip selection, slave selection;

What you will need for connection:

• EMG sensor MYO v1.5 with cable
• Arduino Uno (or another Arduino) with cable
• Fixing tape
• Your PC or laptop

Optionally:

• USB Isolator
• 9V battery

The proper placing of the sensor relative to the target muscle can affect the amplitude and shape of the EMG signal. The most effective way to get an EMG signal is to place sensor along the muscle fibers direction, near the middle area of the target muscle (in the middle between tendors of the muscle).

The sensor can be fixed on skin in two ways:

• with a bandage (any band which can tightly hold the sensor on place with proper contact);
• with a medical tape (a fabric-based or non-fabric one), or sport tape;

NOTE: check the sensor has tight contact with the surface of the skin and does not displaced when muscles contract.

The connection diagram of MYO v1.5 to Arduino is shown in the figure below. To correctly identify the contacts, hold the sensor in your hands with top side up as shown in the next figure below (the patterned wire is always Gnd).

It is the best to connect Arduino to a computer through USB Isolator, or disconnect the computer (and any ather divise connected to computer) from the household power supply. It will protect signal from 50/60 Hz power grid noise and safeguard against electrical shock in the event of the computer power supply system fails or from static charge on computer.

The connection method through the USB Isolator is in the figure below:

1. To program the Arduino UNO controller, use the free Arduino IDE https://www.arduino.cc/en/main/software

2. Download the library from the official Elemyo GitHub page at:
https://github.com/ELEMYO/Elemyo-library. To download, click on the "Code" menu (green) and select "Download ZIP".

3. Launch the Arduino IDE program and install the library. To do this, go to the menu "Sketch -> Include Library -> Add .ZIP Library" and select the downloaded archive. Wait for the library to be installed and restart the Arduino IDE.

4. Connect the Arduino UNO controller to the PC.

5. In the "Tools -> Port" section, select the port to which the Arduino controller is connected.

6. Select the type of microcontroller you are using under "Tools -> Board -> Arduino AVR Boards" (for example, if using Arduino UNO, then Arduino UNO)

7. Open the example distributed with the library "File -> Examples -> Elemyo-library -> EMG_Simple_Read".

8. Upload the example to the board "Sketch -> Upload".

9. After a successful upload, you can visualize the signal using the built-in Arduino IDE Plotter. Go to "Tools -> Serial Plotter" and set the speed to 115200 baud. The plotter will draw two graphs: blue is the original signal, red is the signal envelope.

NOTE: The Arduino IDE 2.x.x plotter have only 50 mkc plotting window, it's too low for observing EMG signal in real time. Please, use plotter from Arduino IDE 1.x.x or ELEMYO_GUI program