Blog  /  EMG Sensors: How Do They Work?

EMG Sensors: How Do They Work?

Electromyography sensors, also known as EMG sensors, measure small electromyographic signals generated by your muscles as you move them. The muscle movement includes clenching your fist, lifting your arm, and even moving a finger. Since EMG sensors diagnose various degenerative nerve and muscle-related conditions, it is a valuable asset in the medical field. Our experts have put together this guide explaining all you need to know about EMG sensors. So let's take a closer look at the electromyography process.  

What is an EMG Sensor?

 
EMG Sensor placement on hands

EMG Sensor placement on hands

  EMG sensors record the movement of your muscles or muscle activity. These sensors are based on the scientific fact that when your muscles contract, they release a burst of electrical activity or an electrical impulse that circulates through adjoining bone and tissue. EMG sensors help rule out and diagnose several muscle disorders like muscular dystrophy or polymyositis. Additionally, this ripple effect is from neighboring skin areas. Therefore, this process helps determine nerve dysfunction, muscle fatigue, nerve-to-music signal transmission problems, and muscle dysfunctionality in real-time.  

EMG Muscular Signal Sensor Features

 
EMG Sensor medical examination

EMG Sensor medical examination

  The following list of EMG muscular signal sensor features measures the activity, expansion, and voluntary contraction of muscles in medical research:
  • Small Form Factor Feature
  • Specially Designed for Microcontrollers
  • Adjustable Gain feature using the onboard potentiometer
  • 5mm Connector
 

How Does an EMG Sensor Work?

 
Wireless body area network

Wireless body area network

  EMG sensors work by placing electrodes or senses close to your muscle groups. These sensors are much more effective on superficial muscles as they cannot bypass the action potentials of superficial muscle tissue. The power activates, and its length decreases during signal processing. Additionally, the muscle, skin, and electrodes move concerning each other. Essentially, EMG signals originate from the electrical activity or electric potential of muscle fibers active during a contraction.  

Types of EMG Sensors

  Two types of EMG sensors are available for application. The first is a surface EMG sensor and a non-invasive technology, and the next is an intramuscular EMG sensor. While both types of EMG differ in the sensor placement, they do share some similarities in the procedure. Let's take a closer look at both types of EMG sensors and how they work.  

Surface EMG sensor or EMG Signal Sensor

  • An essential part of the EMG sensor process is placing the sensor in the correct amount of the muscle or limb. Therefore, palace it in the innervation zone of both tendons to achieve better detection quality.
  • After that, the electrodes detect muscle or limb activation as your muscle tissue starts to move and contract.
  • The electrical activity of muscles detected is visible in waves on the monitor, also known as an oscilloscope.
  • The signal strength is dependent on active muscle or muscle activity intensity.
  • Signal recordings tend to be more effective in individuals with more compliant skin and lower body fat.
  • An essential step in this sEMG sensor process is to cancel the baseline signal fluctuation when recording, as it may degrade signal quality.
 

Intramuscular EMG sensor

 
Intramuscular EMG sensor testing

Intramuscular EMG sensor testing

 
  • The process starts by inserting a sterile needle into the relevant or targeted muscle.
  • Once again, the electrodes detect muscle activation as the muscles move and contract.
  • You may attach an audio amplifier for improved evaluation of appearance and sound.
  • After that, the monitor measures and displays the electrical activity from your working muscles.
 

EMG Sensor Applications

  EMG sensors play a significant role in various biomedical applications such as:
  • Disorders of motor control and Kinesiology
  • Myoelectric signals or control signals for prosthetic hand devices; lower limbs, and arms
  • Diagnosing muscle and nerve disorders in patients for early prevention and treatment
  • Video games
  • Robotic control systems
 

EMG Sensor Arduino Tutorial

 
Electromyogram nerve conduction study

Electromyogram nerve conduction study

  A common problem with EMG devices currently available is their exorbitant cost, significant response time, less amplitude sensitivity, and noise susceptibility. The following EMG sensor tutorial will allow you to connect Arduino with the MyoWare Muscle Sensor to create your electromyography device.  

Required materials

 
  1. Arduino board - Arduino Nano
  2. EMG sensor - MyoWare Muscle Sensor Kit
  3. OLED display - 0.96" 12C OLED Display
  4. Power supply unit- 5V DC Supply
  5. Connecting wires - Jumper Wires
  6. Breadboard
 

Step 1: Preparing the surface

  Start by using soap or a skin cleanser to gently clean and sanitize the area or contact skin you plan to place the MyoWare muscle sensor.  

Step 2: Snap electrodes in place

  Connect the electrodes to the sensor's snap connectors.  

Step 3: Expose the adhesive

  To expose the adhesive, you'll need to remove the film on the backs of the electrolytes and then place them on the skin or forearm muscle.  

Step 4: Sensor placement

  Place a sensor or EMG detector on the muscle during the testing phase. The sensor should be placed so that one of the connection electrodes is positioned in the middle area of the power. It's recommended that you line up the other electrode with the direction of the muscle extent.  

Step 5: Reference electrode placement

 
Electromyography testing while exercising in a key position

Electromyography testing while exercising in a critical position

  This step includes placing the reference electrode on a thin or angular part of the muscle. It should be anywhere near the targeted active power or at a known distance away from the recording electrode.  

Step 6: Connecting to the Arduino board

 
Arduino electronic elements

Arduino electronic elements

  There are one of two ways to connect the implanted electrode connectors. The first way is to connect the electrode connectors to the muscles directly, and the alternative method is to utilize the cable shield now in conjunction with the cable connectors. The supplementary shield contains a long electrode cable, making placing the Electromyography sensor a distance from the computer easy and convenient.  

Step 7: Testing the sensor

  You may begin evaluating the sensor and monitoring the value once you've uploaded the code. Stretch your forearm muscle out to examine the sensor and create muscular contractions, then relax your muscle. Ultimately, these muscular contractions generate a potential analog difference observed on the serial display monitor in real-time. After that, the input EMG channel extracts the EMG signals and feeds them into the self-recovery module in real-time.  

Upload the following code to Arduino

 
 

In a Nutshell

 
Electromyography testing in progress

Electromyography testing in progress

  Electromyography sensors are a diagnostic testing procedure that measures how well your muscles respond to the electrical signal emitted to specialized nerve cells, also known as motor neurons. It's useful for muscle reinnervation, so doctors often order EMG tests if they suspect that a patient or subject has symptoms of neurological or muscular conditions such as unexplained weakness in the limbs or numbness in the muscles. EMG sensors based on surface electrodes are a simple process with minimal discomfort. Ultimately, the results from EMG sensors help prevent or treat muscle and nerve-related disorders. If you have any questions, please get in touch with us.