Getting Started with the MyoWare® 2.0 Muscle Sensor Ecosystem

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Contributors: QCPete, bboyho
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Hardware Hookup

Advancer Technologies has provided a Quick Start and Advanced Guide for the MyoWare 2.0 Muscle Sensor. Feel free to check them out with this guide.

Selecting a Muscle Group

Select a muscle group to place the MyoWare 2.0 Muscle Sensor. Placement of the sensor is critical when measuring the muscle activity. You will need to connect the MID electrode to the middle of the muscle body with the END electrode lined up in the direction of the muscle length. The REF electrode will be adjacent to the muscle body.

Muscle Sensor Placement on Muscle

Image Courtesy of Advancer Technologies taken from the MyoWare 2.0 Advanced Guide

We'll be using the forearm as an example. You can connect the sensor to any muscle group as long as orient the sensor's electrodes with respect to the target muscle as explained above. Note that the muscle group shown in the image below are not to scale.

Muscle Groups

Image Courtesy of Advancer Technologies taken from the MyoWare 2.0 Quick Start Guide

For more other muscle groups, check out the MyoWare 2.0 Advanced Guide. Make sure to zoom in on the image for a closer look at the muscle group. The positions shown in the image are approximate.

Muscle Group Sensor Placement

Image Courtesy of Advancer Technologies taken from the MyoWare 2.0 Advanced Guide

Preparing the Skin

Grab an alcohol swab to clean the skin where the MyoWare 2.0 Muscle Sensor will be placed. Cleaning the skin with soap can leave a residue on the skin and should be avoided.

Alcohol Swab

Clean the skin where the EMG pads will stick using an alcohol swab. A cotton ball soaked in isopropyl alcohol is also sufficient to remove any oils or surface contaminants on the skin. Allow the isopropyl alcohol to evaporate before sticking the EMG pads on the skin

Clean Skin where Sensor Pad will Stick

Stacking Shields

Since the shields are keyed, there's only one way to stack the boards together! Just look for the snap connector labeled as GND or REF. Align the snap connectors. Make sure the power switch is flipped to the OFF position for shields.

Stack Shields Together while Aligning the GND or REF Snap Connectors

Push down on the snap connectors using your thumb and index finger. Make sure to avoid pressing down on the built-in LiPo battery.

Pushing snap pins together on Power Shield Pushing snap pins together on LED Shield

Connecting to a Muscle Group

Snap the EMG pads to the bottom of the MyoWare 2.0 Muscle Sensor. For users using the MyoWare 2.0 Cable Shield, you'll be snapping it to the sensor cable's snap connectors.

Attach EMG Pads

Peel and carefully remove the backs of the electrodes to expose the adhesive.

Remove Adhesive

Attach the pads to the target muscle. In this case, we are using our right forearm.

Attaching to a Target Muscle

Ensure that power is disconnected when stacking shields on the top side of the MyoWare 2.0 Muscle Sensor. Once everything is connected, flip the power switch to the ON position on the Power Shield or LED Shield. For users connecting the sensor to an Arduino and computer, check to make sure that your computer is not connected to the wall outlet. Then flip the power switch to the ON position on the Link Shield.

Connecting Shields to Arduino

For users using a 3.3V Arduino, we recommend adjusting the PWR jumper by cutting the default trace and adding a solder jumper between the center pad and the 3.3V side. For users using a 5V Arduino, you can leave the jumper connected to the 5V side. For more information on modifying the jumpers, check out our tutorial on working with jumper pads and PCB traces.

Cut trace and solder on the 3.3V Side

Stack the Arduino Shield on your chosen development board with the Arduino Uno R3 footprint.

Stacking the Arduino Shield on the Arduino Development Board with Arduino Uno R3 Footprint

Insert the TRS cable between the MyoWare 2.0 Link Shield and Arduino Shield's TRS connector. In this case, we will be using the connector labeled as A0. Make sure to adjust the code when using the other channels.

TRS Cable Between the Link Shield and Arduino

For remote applications, we recommend using a battery pack. In this case, we used AA batteries (NiMH) and a 4xAA battery pack to power the system.

Battery Pack Connected to the System

Make sure to remove the power supply from your computer before connecting your Arduino with the MyoWare 2.0 Muscle Sensor to your USB port. This is to prevent noise and safeguard against electrical shock when connected to the power grid. This includes any computer docks and external monitors.

Remove Power from a Laptop that was Connected to the Main Outlet

Removing power from a laptop before connecting the MyoWare.

When ready, insert the USB cable between your Arduino and computer's USB port.

Connecting USB

For users transmitting sensor data via Bluetooth, attach a battery pack to the RedBoard Artemis acting as the Bluetooth peripheral device. This is assuming that it has the Bluetooth peripheral example code uploaded. Connect the RedBoard Artemis acting as the Bluetooth central device to your computer's USB port. Since the Bluetooth peripheral device is disconnected, you could connect your laptop to a power supply since the MyoWare 2.0 Muscle Sensor is not connected to the main outlet. You just need to make sure to unplug the power supply every time you need to reprogram the RedBoard Artemis acting as the peripheral device.

Bluetooth Example

External Cable

For muscles that require you to mount the sensor pads away from the sensor, snap the MyoWare 2.0 Cable Shield on the bottom of the MyoWare 2.0 Muscle Sensor. Then insert the sensor cable into the 3.5mm TRS connector.

Sensor Cable and Cable Shield

Attach the EMG pads to the snap connectors. After cleaning the skin and selecting the muscle, peel and remove the backs of the electrodes to expose the adhesive. Then attach the pads to the target muscle group based on the MID, END, and REF.

Snap Connector TRS Pin Electrode Pin
[CAB-12970]
Reference [REF] Sleeve Black
End [END] Ring Blue
Middle [MID] Tip Red

Reference Cable

With a hobby knife, slice the reference jumper pad closest to the GND pin. There are traces near the jumper so you will need to make sure to avoid cutting traces that are adjacent to jumper pad. For more information on modifying the jumpers, check out our tutorial on working with jumper pads and PCB traces.

Cutting Reference Jumper Pad with Hobby Knife

Then insert the reference cable into the MyoWare 2.0 Muscle Sensor, slide the pin into the housing with the tab facing away from the board.

Reference Cable Pin Inserting into Jumper Pad

When stacking a shield on top of the MyoWare 2.0 Muscle Sensor, make sure carefully pull the cable away from the shield's snap pin.

Pull Away Reference Cable Wire While Stacking Shields on Top

To remove the reference cable, push the tab into the housing with the end of a flathead screwdriver and gently pull the pin out of the housing.

Push Down Tab and Pull Reference Cable Out of Socket Pull Pin Out of Socket

To close the jumper pad, add a small amount of solder on the jumper pad.

Close Reference JUmper

Disconnecting the MyoWare Shield

When prototyping, you will want to test out different shields or you may need to adjust the trim pot. To remove the boards, you will need a flathead screwdriver. With power off, insert the flathead between the snap connectors and ensure that there are no components in the way of the flathead. Gently slide the flathead between the snap connectors.

Flathead Between Snap Connectors

Angle the flathead against the connectors until the boards disconnect.

Flathead Prying the Shield Off

With one side disconnected, pull the boards away from each other so that the other two snap connectors disconnect.

Remove Shield from Muscle Sensor