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DIY Muscle Sensor / EMG Circuit for a Microcontroller

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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 .

 
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Suchso3 days ago

Any alternate ic for ina106.

Can i use this sensor more than one time ?

hi hello.. i want to use it for my fyp project this month.. can i know more detail about this project.. my email : bill_student46@yahoo.com . and may i now , can i get the signal by using labview software?

kkops1 month ago

can u suggest any reuseable EMG electrodes that will work with this circuit?

Gundanium (author)  kkops16 days ago
The conductive fabric tutorial on our website should work.
oscar2563 months ago

How much is the max amplification for biosignals it has the circuit? Reading a little, i see: G=110 for the INA106. G= -15 for the first opamp, G= -1 for the second opamp, and G=POT/1K for the last opamp. So the final gain is G=(1650)(POT/1K)??? is this correct?? And the max gain is G=165000????

Gundanium (author)  oscar25616 days ago
Right. The max gain isnt usually required
J_Aparecido4 months ago

Hello,

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.

I tried to increase or decrease the gain resistor between pins 5 and 6, but to no avail, however lost sensitivity.

I'm starting in the area of electronics, if someone give some hint where I can find information on, I thank you.

And sorry, my english is not very good, I am "writing" with the help of a translator ...

Thank you,

Gundanium (author)  J_Aparecido16 days ago
Youd probably be best using the raw emg waveform rather than the envelope. Just use an instrumentation amplifier like the first stage of this circuit. Remove DC offset from its ouput with a high pass filter and then amplifier with as much gain as you need to get the sensitivity youre looking for.
AtlasGe8 months ago

dear Gundanium(it seems you are a gundam lover hummm?) i need your help!

i thought i've correctly drawn the .sch file(or at least made it looks like a right one)

also i've tried to turn it into a pcb design

but as i pressed the button 'PCB Quote', there is something wrong and I have nothing to do about it.

what is the signal layer and how to 'put' copper on it?

is it the right way i'm taking?

any kind help is apprecited!

thx

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Gundanium (author)  AtlasGe16 days ago
Id suggest contacting the software maker to help you troubleshoot your issues with their program
KalRob7 months ago

This is great, does anyone have the PDF file of this? I can't download it. Also, what areas would you change/ replace to make this better? Thank you!

Gundanium (author)  KalRob16 days ago
Our Muscle Sensor v3 uses an improved circuit. The schematic is on our website.
dhivya136 months ago

Hi can i ask if this circuit can be used with Matlab software to display results?

Gundanium (author)  dhivya1316 days ago
Yes but youll need a DAQ or some other ADC such as a microcontroller.
rudiclan5 months ago

Hello, I have a problem with the circuit. Sometimes everything works fine and sometimes there is no signal. I used a scope to measure each step an figured out that I have a high DC offset after the first ampification step (AD620 with gain of arround 110). The DC offset is about 800 to 1500mV but I see a oscillation when I use the muscle. Now the signal gets amplified by a factor of 15 and the opamp saturates (constant 8,x V). After the ac couple with the capacitor the signal gets zero. Is it possible to reduce the DC offset or decouple the signal before the second amplification step? Thank you!

Gundanium (author)  rudiclan16 days ago
Check out the schematic for our latest muscle sensor. We improved the circuit to eliminate this problem. However, the still is the potential for DC offset because of the instrumentation amplifier input bias current which can polarize the electrodes. Our next generation sensor addresses this problem. Should be out next year.
thorshammer4 months ago

Hi, I was wondering if it was possible for me to replace the tantalum capacitors with ceramic ones

Gundanium (author)  thorshammer16 days ago
Should be fine
oscar2563 months ago

What is voltage it receives the human body due to the electrodes and
amplifier circuit? Also is it safe to apply to people with pacemakers or
prostheses?

Gundanium (author)  oscar25616 days ago
There isnt built in patient isolation. Always use a battery to power the circuit to isolate the circuit from the power grid.

receiving a greeting hello, I'm working on a prosthetic leg, and I wonder if I can use their entire system for sensors and servos and if so to import the produto, thank you very much

We dont ship internationally for oders taken through our webstore. Some of our distributors do however. I would recommend ordering through one of then.
jrosales58 months ago
How do you know in what part of the body put the three electrodes? For example how i put the electrodes for sense the fingers or my leg or other part of my body?
Gundanium (author)  jrosales516 days ago
You have to first find the muscle body. Then put one electrode in the middle of the muscle and the second a short distance away. And the third on a electrically inactive part of the body such as the bony part of the forarm. You can use an anatomy book to figure out less obvious muscles.

To enable the emg to detect the current that produce by the contraction
of muscle, basically u need at least 3 electrode which is, two of the
electrode must be positioned near to the skeletal muscle, and the other
electrode must be placed in neutral area. Neutral area means that no
muscle tissue on it. The last electrode was used to cancel the noise
that produced.

Gundanium (author)  jrosales58 months ago

That takes some knowledge in Anatomy. It'd consult with anatomical diagrams to figure out where the muscle you want to measure is located. Also, not every body is the same so it might take some trial and error to figure out the best location for the electrodes.

vinay074518 days ago

Does these electordes are used for once.....or can be used for ''n'' times...

Gundanium (author)  vinay074518 days ago
I wouldnt use them more than twice. Ideally only once.

why so..??? can you suggest electrodes which can be used more no. of times....

Gundanium (author)  vinay074516 days ago
Because they are disposable electrodes. The adhesive doesnt adhere to the skin as well after a couple applications. Reusable electrodes usually require you to apply paste or gel to the skin before use. Most arent worth the hassle.
vinay074519 days ago

which type of software is used in that videos....???

Gundanium (author)  vinay074519 days ago
Processing. The example code is on our website.
TalhaA31 month ago

Hi, I want to use this chip for a college project. But there are a few things I'm uncertain about.

How do I get EMG signal to the computer for processing?

Gundanium (author)  TalhaA322 days ago
You have to use a MCU or ADC to convert the signal from analog to digital. Read through our tutorials and documentation to see how to do this.
kkops1 month ago

can u suggest any reuseable EMG electrodes that will work with this circuit?

receiving a greeting hello, I'm working on a prosthetic leg, and I wonder if I can use their entire system for sensors and servos and if so to import the produto, thank you very much

mi correo v23681544@gmail.com

NilayM4 months ago

Hi, I am working on an cost-effective EMG prosthetic as a high school project. I'm fairly new to diy electronic projects so I wanted an expert's take on the capabilities of the muscle sensor r3 kit. For my needs, I wanted to know if multiple kits(2 or 3) could be connected to the same arduino uno(I will probably be investing in an arduino mega soon, so is it possible in that too)? Also, with the data that the emg sensors collect, will I be able to use that to control a set of motors independent of a computer's presence. Unfortunately, I am in a time crunch and need answers very soon, so any response would be much appreciated. Thank you for your time and expertise.

Gundanium (author)  NilayM4 months ago
Hi Nilay, you can indeed use multiple sensors per microcontroller. However, you can't directly drive a motor with the sensors. You'll need to use a microcontroller or a servo control board to read the sensor data and control the motor accordingly.

Cheers,
Brian
oscar2568 months ago

What is voltage it receives the human body due to the electrodes and amplifier circuit? Also is it safe to apply to people with pacemakers or prostheses?

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