Measuring muscle activation via electric potential, referred to as electromyography (EMG) , has traditionally been used for medical research and diagnosis of neuromuscular disorders. However, with the advent of ever shrinking yet more powerful microcontrollers and integrated circuits, EMG circuits and sensors have found their way into prosthetics, robotics and other control systems. Yet, EMG systems remain expensive and mostly outside the grasp of modern hobbyist.

This instructable will teach you how to make your own muscle sensor / EMG circuit to incorporate into your next project. Use it to control video games, robot arms, exoskeletons, etc.

Click on the video below for a demonstrations on how to hook up and use your EMG circuit board!

You can now also purchase  EMG sensors, kits, cables and electrodes at www.AdvancerTechnologies.com!
Muscle Sensor Kit (now also on SparkFun)
Muscle Sensor Electrodes

Note: This sensor is not intended for use in the diagnosis of disease or other conditions, or in the cure, mitigation treatment, or prevention of disease, in a man or other animals.

About Advancer Technologies 
Advancer Technologies is a company devoted to developing innovative game-changing biomedical and biomechanical technologies and applied sciences. Additionally, Advancer Technologies promotes all forms of interest and learning into biomedical technologies. To help culture and educate future great minds and concepts in the field, they frequently post informative instructions on some of their technologies. For more information, please visit www.AdvancerTechnologies.com .

Step 1: Materials

Click on the links to go to where you can buy items/order free samples.

Circuit Chips

3x TL072 IC Chip  - Free Samples
1x INA106 IC Chip  - Free Samples

Cables and Electrodes
1x EMG Cables   (set of 3)... Note: you could optionally connect the alligator clips directly to the electrodes.
3x EMG Electrodes  

2x 9V Battery
2x 9V battery clips  

• 2x 1.0 uF Tant 
• 1x 0.01 uF Ceramic Disc  
• 1x 1.0 uF Ceramic Disc   

• 3x 150 kOhm 1%  
• 2x 1 MOhm 1% 
• 2x 80.6 kOhm 1%  
• 6x 10 kOhm 1%
• 1x 100 kOhm Trimmer 
• 1x 1 kOhm 1%

• 2x 1N4148 Diode  
Jumper wires
• 3x Alligator clip cables

• 1x Oscilloscope
• 1x Multimeter


To start things off, you’ll need both a positive and negative voltage power supply. We will make these using two 9V batteries.

Now, everyone knows what a positive voltage power supply is, (e.g. common battery) but how do you go about making a negative voltage power supply?

Common electrical circuit rule of thumb is when you connect two batteries in series (eg positive terminal of battery 1 connected to the negative terminal of battery 2) then measure the voltage from the negative terminal of battery 1 and the positive terminal of battery 2, the measured voltage is equal to the summation of the voltages of battery 1 and battery 2.

For this circuit we want a +9V and a -9V power supplies. If we connect our two 9V batteries in series, we will get a power supply of +18V. So how do we get the -9V from these two?

It might help to think about what voltage actually means… voltage is an electrical potential difference. The keyword here is difference. Voltages are only meaningful in terms of the reference point (or more commonly referred to as ground). A voltage is the electrical potential between this reference point and the point you are measuring. Do you see the answer yet?

We do indeed get a +18V voltage reading if we use battery 1’s negative terminal as the reference point… but what if we choose the connection between battery 1’s positive terminal and battery 2’s negative terminal? If we use this point as our reference or ground, then battery 2’s positive terminals voltage will be +9V and battery 1’s negative terminal will be -9V!

Using your breadboard, 9V batteries and battery clips, connect the battery clip wires as shown. However, for the time being, disconnect the positive terminal of battery 2 and the negative terminal of battery 1. It is good practice to always disconnect your power while you assemble a circuit. At the end of the assembly we will reconnect these wires to power the circuit on. (You could also add switches to do this)



Next, we will work on the signal acquisition phase of your EMG circuit which we will use to measure your body’s nervous system’s electrical impulses used to activate muscle fibers.

First, get out your INA106 IC chip (chip A) and insert it into your breadboard as illustrated above. The INA106 is a difference amplifier which will measure and amplify (G=110) the very small voltage differences between the two electrodes you place on your muscle.

Next, grab two 1 M ohm resistors, bend them and then plug them in to your breadboard like the two examples shown. One should connect pins 5 and 6 and the other should bridge pin 1 to your ground rail of your board.

Don’t worry about the other pins of the INA106 for now; we’ll come back to those later.

Step 4: SIGNAL CONDITIONING - Amplification

In this phase, we’re going to take those very small signals measured in the SIGNAL ACQUISITION phase and amplify them.

Let’s start first with two series of amplification; the first will be inverting amplifier with a gain of -15. An inverting amplifier does exactly what it sounds like. It amplifies your signal but also inverts it. You can find more info about inverting amplifiers here

We are going to first build an inverting amplifier with a gain of -15. To do this, we’ll need one of the TL072 chips (chip B), one 150 kOhm resistor and a 10 kOhm resistor. 

Place chip B as the picture indicates. Now use a jumper wire and connect pin 6 of chip A two rows past pin 8 of chip A. Grab one of the 10 kOhm resistors and plug one pin into this row as well. Connect the other pin to pin 6 of chip B. Bend a 150 kOhm resistor and connect one pin to chip B’s pin 6 and the other to pin 7. You can calculate the gain by G=-R2/R1 or in this case G=-150 kOhm / 10 kOhm. (See image 1)

Next, we are going to add a capacitor to AC couple the signal. AC coupling is useful in removing DC error offset in a signal. Read more about AC and DC coupling here

Continuing on, we are going to add an active high pass filter to get rid of any DC offset and low frequency noise. To do this you will need two 150 kOhm resistors and a 0.01uF capacitor. Use a jumper wire and the 0.01 uF capacitor to bridge the center gab of your breadboard as shown. (One end of the jumper wire should be connected to pin 7 of chip B). The 150 kOhm resistor will connect the capacitor you just placed to pin 2 of chip B. Now, bend the 150 kOhm resistor and push it into connect pins 1 & 2. (See image 2)

Also, go ahead and connect chip B’s pin 4 to your -9V rail, pin 8 to your +9V rail, and pins 3 & 5 to your GND rail.


Step 5: SIGNAL CONDITIONING - Rectification

In this phase, we will be rectifying the signal using an active full-wave rectifier . Our rectifier will take the negative portion of our signal and turn it positive so the entire signal falls within the positive voltage region. We will use this coupled with a low pass filter to turn our AC signal in to a DC voltage; readying the signal to be passed to a microcontroller.

You will need five of the 10 kOhm resistors, both 1N4148 diodes, and a second TL072 chip. Warning… this will be the most difficult phase to assemble! Pay close attention to the pictures!

First, plug in a TL072 chip (chip C) and connect -9V rail to pin 4, the +9V rail to pin 8 and GND to pin 3, as shown in the first image.

Next, place a 10 kOhm resistor (let’s call it resistor A) connecting pin 1 of the TL072 chip from the amplification phase and plug the other end into the row next to the 0.01uF capacitor’s row. Use a jumper wire to connect this row to pin 2 of the second TL072 chip. The next 10 kOhm resistor we’ll call resistor B. Resistor B’s first pin should be plugged into the row where resistor A’s second pin is plugged in and resistor B’s other pin should be plugged into the row two down. Another 10 kOhm resistor’s (resistor C) first pin should be plugged into the row where resistor A’s second pin terminated (same as resistor B) but the other pin should be plugged into the next immediate row over. (See image #2)

Now get out the two 1N4148 diodes. Diodes are polarized so be sure to pay attention what direction you plug them in! We’ll call these diodes A and B. Plug diode A’s positive end (end with black strip) into pin 1 of chip C and plug the negative end into the row of resistor C’s second pin. Get diode B and plug the NEGATIVE end into pin 1 of chip c and plug the POSITIVE end into the row of resistor B’s second pin. (See image #3)

Next, use two jumper wires to bridge the center gap for resistor C and B’s rows. Use another jumper wire to connect the jumper wire’s row connected to resistor B’s row to pin 5 of chip C. Use another 10 kOhm resistor to connect the jumper wire’s row connected to resistor C’s row to pin 6 of chip C. Finally, use the last 10 kOhm resistor to connect chip C’s pins 6 and 7. (See image #4).

Phew… that is for the rectifying phase! Next is the filter phase.

Step 6: SIGNAL CONDITIONING - Smoothing + Amplification

In this last phase of circuit assembly, we will be using an active low-pass filter to filter out the humps of our signal to produce a smooth signal for our microcontroller.

You will need the last TL072 chip (chip D), the two 80.8 kOhm resistors, the 100 kOhm trimmer, the 1 kOhm resistor and the 1.0 uF ceramic disc capacitor.

First, plug in chip D and connect +9V to pin 8, -9V to pin 4, and GND to pins 3 & 5. (image #1).

Now, grab one of the 80.6 kOhm resistors and connect one end to chip C’s pin 7. Connect the other end to chip D’s pin 6. Next grab the other 80.6 kOhm resistor use it to connect chip D’s pin 6 and 7. Do the same thing for the 1.0 uF capacitor. (image #2)

That’s the end of the filter circuit. However, since this is an active filter, there is a side effect of inverting the signal. We will need to invert the signal one more time (and have the ability to amplify it more if desired) using another inverting amplifier circuit with a trimmer configured as a variable resistor.

Use a jumper wire, connected to chip D’s pin 7, and the 1 kOhm resistor to bridge the board’s center gap. Use another jumper wire and connect the 1 kOhm resistor to chip D’s pin 2. Next, place the trimmer one row over with the pins laid out and a jumper wire connecting two of the pins as pictured. Finally, place the last two jumper wires as indicated. (image #3)

By using a screw driver and turning the trimmer, you will be able to adjust the gain of your signal to account for different signal strengths from different muscle groups. Start out with it set pretty low and go up from there (~20 kOhms).

Step 7: Circuit Review

(Optional) If you have an oscilloscope and a wave generator handy, now would be a good time to step through the circuit and test each phase.

If you do not have an oscilloscope handy, go back and review your circuit connections step by step to make sure you have place each component correctly. Pay close attention to the power pins and connections of your chips. If you have these incorrect, you could burn out your chips!

Step 8: Electrode Cables

Next, you'll need to make some changes to the EMG electrode cables since I have been unable to find a vendor who sells the cable's style DIN connector's female compliment.  (if any one has a suggestion please let me know!)

Grab a pair of scissors, wire cutters, wire strippers, pocket knife, etc.... basically anything sharp and strip about a 1/4" of the end of the DIN plug on all three cables (the plug end not the snap end).

Next, clip an alligator cable to each of the wires. We will use these to connect the electrode cables to our breadboard with some jumper wire. You could do as I have done and strip the wire and then solder on terminal pins but it is not necessary and the alligator clips will do fine.

Step 9: Surface Electrodes

For the electrode placement, you will need three surface electrodes.

After determining which muscle group you want to target (for example I will be using my right bicep) and cleaning the skin thoroughly, place one electrode on your skin above the middle of the length of the desired muscle. Let's call this the mid muscle electrode.

Next, place a second electrode at one end of the muscle. We'll call this the end muscle electrode.

Last, place the third electrode on a bony part of your body nearby the muscle group. We'll call this the reference electrode. For example, for the biceps, I am placing the reference electrode on the bony end of my forearm close to my elbow.

Using the snap connections of the electrode cables, snap each cable to each electrode. Make a mental note of which color cable is attached to which electrode.

Step 10: Connecting Electrode Cables

Now you are ready to connect your electrode cables to your circuit. Remember those pins on chip A that we put aside till later?

Connect the reference electrode to the GND rail of your circuit.
Connect the mid muscle electrode to chip A's pin 2
Connect the end electrode to chip A's pin 3

Lastly, we need to add some circuit protection via capacitors. Tanthium capacitors are polarized like the diodes we used earlier. These are easier to tell which is the positive pin and negative pin since one is always marked with a + sign indicating positive pin. Connect one 1.0 uF tant. capacitor between the +9V rail and GND rail, with the positive end connected to the +9V rail. Connect the other 1.0 uF capacitor to the -9V and GND rails, with the positive end connected to the GND rail.

Now you'll ready to power on your circuit!

Step 11: Connecting to a Microcontroller

Before connect your circuit to your microcontroller, you should power on your circuit (by connecting the battery wire's we disconnected earlier) and check the output voltage with a multimeter to make sure it is within your microcontroller's analog input pin's tolerances. To do this, connect the negative multimeter probe to your GND rail and connect the positive probe to pin 1 of chip D. Make sure the voltage measured is less than the max voltage of your input pin!

If you've done that check and everything thing looks fine, use jumper wires to connect pin 1 of chip D to an analog input pin of your microcontroller and your GND rail to the GND pin of your microcontroller.

Congratulations you're done!

Step 12: Arduino Demo

For this demo, we used an Arduino Duemilanove microcontroller hooked up to a PC running Processing visualization software. 

Remember to visit us at www.AdvancerTechnologies.com for kits and fully assembled sensors!

Step 13: EMG Circuit Schematic

Click the i box in the top left to see a larger version... or go to our website and click on the EMG schematic image .
<p>what programs and code for arduino you used for the data acquisition and the visual representation of the emg signals?, thanks for your time and for your project (:</p>
Hi The sample code can be found on our website: http://www.advancertechnologies.com/p/muscle-sensor-v3.html
<p>Can we use homemade electrodes from nickel buttons to provide the input for sensor</p>
<p>Hi I'm using your circuit as part of a control mechanism for an exoskeleton. I have made the circuit however I'm getting errors when running the codes for processing and no readings on the graph specifically with the Line 60 in the bar graph processing code: println(Serial.list));. The error is &quot;Type strin[] of the last argument to method println(object...) doesn't exactly match the vararge parameter type. Cast to object[] to confirm the non vararge invocations or pass individual arguments of type object for vararge invocation&quot;</p>
<p>Can we use this circuit for ECG purpose of brain and heart ???</p><p>Please reply me fast</p><p>Thanks</p>
<p>I recently made this circuit on a breadboard. But the circuit does not show any output on the Arduino serial plotter when the given Arduino code is used. Can someone please help me out with this? I need to know what could have gone wrong?</p>
<p>I will be needing more than 3 electrodes in my system. So naturally I will be needing more than 1 INA106. But it is exceeding my budget. So i wanted to know if there's a cheaper alternative to the INA106 IC?</p>
<p>Instead of using wires, is it possible to make this system wireless, especially the microcontroller? And how do i do it?</p>
You can't eliminate the wires going from the electrodes to the circuit but it should be possible to eliminate wires going from the circuit to the microcontroller. In simplest terms, you'll need to send the output through a ADC converter and then a Bluetooth or Wifi transmitter.
<p>Ok! Can you tell me how exactly to make the connection from the circuit to the controller wireless? Could you please provide me the instructions to do it?</p>
<p>Can we connect more than 3 EMG electrodes in this same setup?</p>
No this circuit is for one muscle (three electrodes). You'll need to duplicate the circuit for every set of electrodes or you can multiplex after the IA phase (would still need an IA per muscle aka set of electrodes).
<p>Oh alright! Thanks</p>
<p>can we have PCB schematic i would lie to print it also can i use ina 129 instead ina 106.</p><p>thanks </p>
<p>I am trying to use the processing code but i keep getting the error &quot;the size of your sketch could not be determined&quot; , any advice? Sorry, I am new to coding.</p>
<p>Hi,</p><p>Code for this experiment can not found in the url which you gave a year ago.</p><p>Where can I find?</p>
Hi halaskar,<br><br>We moved all our code and documents to a GitHub repository.<br><br>https://github.com/AdvancerTechnologies/MuscleSensorV3
<p>Can we use Arduino UNO instead of Arduino Duemilanove ...???</p><p>Please Help ..</p>
Yup any arduino will work. Most microcontrollers will work as long as they have analog input pins (e.g. raspberry pi will not work without interface hardware)
<p>hello,i have a muscle sensor and a cable to connect electrodes with sensor. Problem is that color of cable connector is green,yellow,and red,Instead of red,black and blue.and i have little bit confused about connections.On green cable &quot;F&quot; is written,on yellow &quot;L&quot;,on red&quot;R&quot;. Please advice me. Thanks</p>
<p>Hello!</p><p>I am using an INA118 to sense EMG but the only thing I can see is the 60Hz noise. Why is it not rejecting the common mode noise? It has a high CMRR. I am using a power supply +- 9V and the RG=240ohms (Gain about 200). The refference pin is connected to ground and I am using three wires to connect to the body. The ground and the two input pins of the INA118 (+ and -). The wires are single wires, not blinded and not twisted. Can you give me any hint? My circuit is exactly the same as the Advancer sensor V3, a little different from yours with INA106. My next move will be to assemble with the INA106 if I cannot make my current circuit work. Thank you!</p>
<p>Picture of the EMG activity I measured with this project. So cool :)</p>
<p>What type of data visualization software are you using? I'm doing a research project with making this EMG sensor, and I think this software would be perfect for my project. </p>
<p>hi, I love this project. where can you provide more information about it. i would like to use it as my bachelor project</p>
<p>It was a nice experience :)</p>
<p>Hi,Gundanium i'm new in electronics so could u please tell me the connection needed if i replace the INA 106 with AD620 </p>
<p>Hello,<br>my research need to use amplifier with 2 electrode..<br>is this circuit compatible by using 2 electrode..</p>
No you'd need to design a new circuit that doesn't use a differential amplifier to only use 2 electrodes. This is called monopolar EMG. The main issues with monopolar EMG is that, unlike the bipolar EMG, noise (e.g. 60Hz hum) is not eliminated by the op-amp so you have to design more sophisticated filters to remove the noise. This is taken care of inherently by bipolar EMG since they employ differential amplifiers with high CMRR (common mode rejection rate) which eliminates noise common to both electrodes.
<p>Hi, great tutorial, a friend and I built a modified, monopolar version of this circuit for a project a few years back, and we certainly did see a lot of signal noise. However, looking back on the circuit diagrams, I am now curious: What would be the harm in using a monopolar design, but rather than using a mid-muscle sensor and a neutral reference point, using a mid- and end-muscle electrode? Isn't that the voltage difference that's being amplified anyway? And if you set it up that way, you wouldn't have to worry about noise common to both electrodes, right? Because you wouldn't even be able to observe that noise to begin with? I get that there is probably a good reason it was designed as it was, but I am having difficulty seeing what the consequences would be of setting up a system like that. Is it somehow that the measured voltage is actually between the mid muscle sensor and the bone, and the other muscle sensor is primarily to reduce common noise across the entire muscle? For reference, I am a mechanical engineering student with a background in computer science, mostly hands-on experience with electronics, and a cursory understanding of anatomical systems. Thanks in advance</p>
<p>Hi I am not an electrical engineer. I am doing a lab project<br>with EMG elecrodes that read small facial muscle EMG signals via surface<br>electrodes. I just need an indicator (such as a buzzer or flashing light) to go<br>off when the small muscle is stimulated.<br>Would any of your sensors serve that purpose for me? How would I set up that<br>circuit? Thank you</p>
Yes it would be suitable for your application. Our new sensor the MyoWare actually has an on-board LED that is driven by the output signal. https://www.kickstarter.com/projects/312488939/myowaretm-harness-the-power-of-your-muscle-signals
<p>Hi,</p><p>i did the correct circuit but in output i have small tension (0.290mv) do u think i burn some components?</p><p>thank you for ur help</p>
<p>Don't you compromise the common mode rejection by boosting the front end gain with external 1M 1% resistors? CMRR is the prime consideration digging small differential signals out of the background hum! The INA10 has spectacular CMRR and gain accuracy because it has finely (and expensively!) laser matched resistors. I would have thought it better to up the gain in the 3rd stage, which is currently unity.</p>
<p>Hi there, very cool stuff! What program were you using on your mac to show the emg? Thanks!</p>
<p>hey gundanium. i am working on this sensor and want to controll a wheeled robot or a robotic arm. i would highly appreciater ideas in this regard about how to work on that.</p>
<p>Hi every body , I have done the Circuit above there and i want to connect a servo motor using arduino uno and electrodes could any body have any idea about that thank you in advanced</p>
<p>DIY Muscle Sensor / EMG Circuit fohi, may we connect servo motor on the breadboard or Arduino to control them with the EMG system,thanks in advance </p>
<p>hello and good day. im working on my fyp which is related to the hand gesture in controlling home appliance. by using the coding given, i am actually stuck and confused to what actually this sensor will displayed. i dont know if im on right track or not. as there is no further explanation on it. and how i can drive a dc motor from the muscle signal output by using arduino uno. please help me and thank u if u can help me..T_T</p>
<p>What's a good alternative to the TL072 and INA106? I think they don't sell them here.</p>
<p>can u tell me the output voltage of this diy muscle sensor on pin 1 of chip D and ground and another question is can i use the schmitt trigger on the input of ardunio.</p>
<p>Hi,</p><p>I am doing a project on Measurement of ECG signals using <br>Textile electrode.</p><p>I have some doubts. I request you to help me.</p><ul> <br><li>I have two textile conductive fabric electrodes E1 &amp; E2 (+/-) <br>which can be placed in chest. Is it required to use electrode E3?<li>What type of electrode can be used for ground <br>(E3)?... Conductive fabric?<li>Do I have to excite the electrode?</ul><p>Please reply me as early as possible.</p><p>Kindly give me some materials on Textile electrodes <br>measurement and its signal conditioning circuits. (Email ID: aashajoe@gmail.com)</p><p>I am waiting for your reply sir.</p>
<p>I have a question about the basic materials required.</p><p>I don't see the Arduino or Breadboard listed in the materials.</p><p>What boards do I need to accomplish this project if I order everything in the materials list?</p><p>This is my first time working with electronics on this level. Thank you.</p>
<p>Hi, Actually i m making a battery plates tester, in which i pass 21Amp and 5V dc across the the plate, and the voltage drop across the plate is 0.3mv to 0.4mv , if drop is 0.3mv it is satisfactory, and if it is 0.4vm that is not satisfactory, <br><br>i m using instrumentation amplifier, ad620, to detect the small signal and amplify it to certain voltage, then i compare the two voltages by using comparator is lm324, but the problem is that it produces chattering in relay operation , i have added hyterisis but it still produces chattering</p><p>kindly help me </p>
<p>actually there are two wires in the EMG electrode cable.how can we connect to the circuit?</p>
<p>Actually there are two wires in EMG electrode cable(red and white).how can we connect to the circuit?</p>
<p>Hi, Gundanium. Im trying to build the sensor and was curious about what are the improvements I should make t&ocirc; the project t&ocirc; add two more channels? Should I double the circuit os there are other alternatives? Im no eng, but a biophysicist and enthusiast of tech and electronics. Thank you</p>
You basically would need to duplicate the circuit 2 more times to add 2 more channels. There are technical obstacles that will prevent you from using more elegant solutions like muxing.
<p>Hello,</p><p>I managed to assemble this project is operating normally ... like a hint, how can I increase the sensitivity of the circuit? For example, if I want to monitor variations in electrical potential without even having muscle contractions, or in a state of relaxation or strees would be an example. </p><p>I tried to increase or decrease the gain resistor between pins 5 and 6, but to no avail, however lost sensitivity. </p><p>I'm starting in the area of electronics, if someone give some hint where I can find information on, I thank you. </p><p>And sorry, my english is not very good, I am &quot;writing&quot; with the help of a translator ... </p><p>Thank you,</p>

About This Instructable


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Bio: Brian Kaminski Owner - Advancer Technologies Brian graduated from North Carolina State University with a BS in Biomedical Engineering with a concentration in Biomechanics in May ... More »
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