Muscle Sensor v3

Muscle Sensor v3
AT-03-002


Description: This sensor will measure the filtered and rectified electrical activity of a muscle; outputting 0-Vs Volts depending the amount of activity in the selected muscle, where Vs signifies the voltage of the power source. Power supply voltage: min. +-3.5V 

Features:
  • Improved adjustable gain (more rugged)
  • On-board port for our new cables
    • Connects to the board straight out of the box
  • Reduced voltage needed (+-3.5V)
Dimensions: 1.0" x 1.0"

Documents: 
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Wiring Instructions:
  1. To use this sensor, the user must have three electrodes connected to the subjects body.
  2. The reference electrode should be placed on an inactive section of the body, such as the bony portion of the elbow, shin or forearm. This electrode should be connected to the black or brown cable.
  3. The two other electrodes should be placed along the muscle selected to be measured. The second electrode should be placed along the mid length of the muscle; this electrode should be connected to the red cable.
  4. The last electrode should be placed at the end of the muscle and connected to the blue cable.
  5. Finally, connect pin SIG to an analog input pin of your microcontroller and the GND pin to the ground pin on your microcontroller.

WARNING: As an inherent risk associated with electrical component work, improper use of this sensor could cause harm to the subject. If underage, do not use without adult supervision.

WARNING: 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.

84 comments:

  1. Hey, is it possible to get a two-channel or even 4 channel board to measure the muscle activity on different regions of the body at the same time? does this board connect to an arduino?

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    1. Hi! This sensor is a single channel board. However, you can use more than one at the same time. Yes, this board connects to an Arduino. Check out the User's Manual (linked under Documents) for step by step instructions on how to connect it.

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  2. Also would the setup be easy to adjust to make it wireless and wearable? Does it recognise different thumb and finger taps for example? And how are you getting the readings from the EMG to the computer. Do we need to handle that? Are you using your own machine learning?

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    1. I think you're slightly misunderstanding. We only sell the analog sensors, what and how you integrate them into a digital system is totally up to you (and most of the fun).

      I would suggest reading through our user's manual (link is up above). It'll answer most of your questions.

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  3. The smoothing stage after rectifier consists of a capacitor and resistor in feedback.
    this configuration is for active low pass filter. With 1 u capacitor with 80.6k resistor.
    The cut off frequency comes out to be 1.97 HZ. Am i right? What is the reason for this cut off frequency?

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    1. Correct. The low pass filter smooths the rectified signal. There's a section explaining this in the User's Manual. I suggest checking it out.

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    2. I was also wondering the same thing as the above commenter. With LPF, it does smooth the signal; however, with ~1.97Hz cut-off frequency, would that erase the normal defined EMG frequency range 0-500Hz?

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    3. If there any explanation regarding to the cut-off frequency? since the EMG frequency range defined as 0-500Hz.. I have read through the user's manual, but could not find it..

      thanks for your respons

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    4. No because the smoothing acts on the rectified signal not the raw signal. I suggest reading through the user's manual for visuals of what's going on.

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    5. I dont get it .What does acting on rectified signal /raw signal has to matter? Anyway the raw signal itself is being rectified and passed on to the smoothening stage right?So isnt it like we are cutting the major portion of the emg signal?

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  4. Hi, I'm interested in using this with the IOIO board, which only accepts 3.3V analog inputs. Is there a way to reduce the output voltage, e.g. using a voltage divider? Thanks for your respons.

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    1. Most boards can accept slightly higher voltages than they can measure. I'd suggest using +-3.5V power supply to power the sensor. This make its max output 3.5V.

      You could also simply lower the gain using the potentiometer.

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    2. Thanks for the reply. Will lowering the gain lower the max output voltage, or just change the input voltage for which the max output voltage is reached?

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  5. Hi,

    I want to use a frequency of 1000Hz and 500Hz (1000 samples/second and 500 samples/second) for my project. Can this sensor handle it? What is its maximum limit?

    Thanks

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    1. Hi,

      The output is an analog signal, therefore, the sampling rate depends on the measurement hardware not the sensor.

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  6. Hi!
    I'm a musician interested in using this sort of technology to make non-"musical" sound, but am not particularly electronics savvy.

    Would I be able to run a signal from this my body, through this unit, into, say a guitar pedal and into an amp? what kind of sound signal would my body be sending? clicks? are there any videos of this sort of interaction with this device?

    very curious!

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    1. This sensor outputs a rectified EMG signal so it's very different than an audio signal. Raw EMG signals more closely resemble audio. You could use our sensor to have an MCU convert the output level to a pitch or tone but simply hooking the output up to a speaker probably wouldn't do much.

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  7. Can i use 4 of this sensor and share with just 1 reference electrode. Im trying to sense 4 difference muscle group and having 9 electrodes connected to the body 4x4 for each muscle group and 1 electrode as reference and shared into 4 sensors so i could reduce wirings and electrode hook ups.

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    1. I usually recommend a ref electrode per side of the body you are using. For example, if you are measuring activity from biceps on both your left and right arm, I would use a ref electrode for each arm (2). If you are measuring the activity of your bicep and forearm on the same arm, then you would only need 1 ref electrode.

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  8. HI..! I am making a myo elctric arm of disabled people. Is one muscle sensor V3 kit enough to control all the movements of five fingers or do we need one sensor kit for each finger?

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    1. Each board is a single channel EMG so you will need a sensor board per muscle.

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  9. Hi Brian, this looks like a great product, mega props for building it. I look to implement your design to make a little side-scroller controller for demoing to 1st-year students the endless possibilities of an EE degree. :)

    I have two questions: in your schematics, you specify using TL08x OA units for the HP (rectifying) & LP (smoothing) stages. The TI specs state a +/-5V min VCC/VDD, but in the product description you mention that the device may be powered by +/-3.5V rails. Am I missing something? :\

    Secondly: I hoped to power the device at +/-4.5V (9V with a rail-splitter) so as to feed into my 5V-max Arduino, and was considering using MCP604s in place. Do you think the 2.3V/us slew rate would cause too much latency?

    Thank you so much for your advice, and best of luck with future developments! ~Liam

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    1. Hi Liam,

      The TL084CPT actually has a min voltage supply of +/-3V. I'm not familiar with the MCP604 so I can't really offer any advice. Let me know if you have anymore questions!

      Cheers

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  10. hi..! i am making a prosthetic arm for disabled people..
    i have 2 sensor kits of V3.. i gave +5 and -5V as supply voltages and i gave all the other connections as per the manual mentioned in ur site. I connected the sensors to the bicep muscle and i connected the sig pin and gnd of of the output to the CRO.. all that im getting is noise signals and nothing else... PLease help me .. do we need to change the gain on the PCB..??

    kindly tell me any solution to this problem if possible.. any assistance of u would be of great help to me..!

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    1. Hi Kartik, send us an email with pictures of your setup. It sounds like it is something wrong with your setup. Pictures helps us pick them out right away. Few things to check: 1) Use a multimeter to verify you are getting +5V and -5V on the +Vs and -Vs pins, respectively; 2) Make sure you use new electrodes at each use, the one's that come in the kit are NOT reusable; 3) Make sure the blue and red cable electrodes are about 1 inch apart from each other.

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    2. thanks for your reply. ive checked all the parameters uve mentioned and i made sure that blue and red electrodes are more than 1inch apart from each other.. but even then im just getting noise as output when connected to a CRO. and i used new sensors all the time.. could there be any other reason of the setup not working?
      and can u mention the email id to which i should mail the pics of the setup.!

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    3. Our email is on the "Contact Us" page (link is on the bar at the top of this page)

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  11. I am currently using the EMG sensor to output into a lillypad micro-controller (same as an arduino). It can only take an input of 5V max.

    I am finding it very difficult to work out how to best power the device using batteries, as it has to be worn by the user (must be small/light).

    How can i generate a +/- 5v, or even 3-5V (as long as it does not take away from the circuits performance or resolution)??

    I need the circuit/battery to be small but still last awhile (min 1hr).

    Any help would be really appreciated!!

    Thanks in advance.

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    1. If you are using a micro, you can use a few spare micro controller pins to drive a charge pump, it should be able to drive the negative rail for the circuit. just make sure that the negative rail is not overloaded

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    2. The lilypad can only read up to 5V you can safely input voltages higher than 5V. However, any signal over 5V will saturate the ADC and will only read as 5V.

      You can use 6xAAA batteries to make a +/-4.5V power supply. Or you can use a circuit similar to this one(https://docs.google.com/file/d/0B8Wy2qiwirwyYWM1OWM1MGItZDIxMS00YjQ0LThkNjUtYTExYTAxYzU1YzNi/edit?usp=sharing) to make a +/-5V regulated power supply. There's many ways to make a dual power supply so I'd also recommend browsing around on Google to find a solution that would be a good fit for your application.

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  12. Hi there, thanks for keeping the knowledge open! I'm looking at building a robot based on your design.

    In the input stage, the gain is set at ~206 V/V, can you please let me know what Vrms you are getting after the high pass at R7? I've tested building an instrumentation amplifier and have found that I need a gain of over 1000V/V before the signal gets past rectification.

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  13. hi there, i wanted to ask that does this sensor kit measure only one muscle movement at a time? actually i am working on a project of upper limb exoskeleton controlling 3 DOF so need to figure out no. of sensors required for this purpose as many muscles are controlling the movement of upper limb.i would appreciate if you could help.

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    1. This sensor measures only one muscle. You'd need to purchase a sensor for each muscle you wish to monitor.

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  14. I know very little about electronic hardware and have spent most of my time on analyzing the outputs when other individuals have handled the hardware side. I am trying to learn so I purchased the EMG V3 sensor. I attempted to attached the sensor to 2 9V batteries as indicated in the instructions but the unit just started smoking. Can you please tell me what I might have done wrong? I followed the directions as specified. Thank you.

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    1. Sounds like you accidentally reversed the polarity while hooking up your power supply. This will burn out the sensor.

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  15. Hi! We're interested in using your muscle sensor to an Alduino Uno board as a part of our school design project.

    One question: What if we want the raw sine wave EMG data instead of the rectified and smoothed sine wave? Is the signal processing implemented in the sample Alduino/Processing code that is provided? Or is it something that is intrinsic in the circuitry of the sensor? If it is implemented within the circuitry, could you make it so that we get the raw EMG data instead of the rectified and smoothed sine wave?

    Much thanks in advance,

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    1. Hi, the rectification and signal processing is part of the circuitry. As of right now you can't get the raw EMG waveform from the sensor. We plan to add that ability to the next version ('14-'15 time frame). If you want the raw signal, I would suggest checking out an AD620 IC chip.

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  16. Is there any way to turn this single-channel board into two or more channel?

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    1. You can use more than one board at a time. Some of our tutorials use more than one board if you need an example of how to do this. You cannot modify a single board to give multiple channels.

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  17. Hello,
    I am in the infancy of research into prosthesis design and EMG technology. I am planning/dreaming to make a prosthetic hand for my dad. His arm was amputated 3” below the elbow, 30 years ago. I am going to buy some of your sensor kits to experiment with and possibly incorporate into my final design, so please humor some of my non-product-specific questions; I’m sure you know, or have a good idea about the answer, at least more than I do.
    #1- where can I pick up signals for wrist rotation and flexion when the wrist is gone?
    #2 – I notice in your videos, you are utilizing large muscle groups. Are your sensors, or ANY EMG sensors (including the medical grade ones) sensitive enough to even pick up 5 individual finger signals? If so, can they do it to such a degree and resolution to perfectly imitate a human hand (assuming electrical and mechanical design of the hand is flawless)? It’s ok to say no, I’ll still buy them.
    #3 – Where can I pick up EMG signals for fingers that are no longer present? My SWAG is that there will be 5 nerve endings somewhere on the end of his nub where I can pick up the individual finger signals. But after watching your videos, I’m thinking maybe on the top of the forearm.
    #4- can you recommend any required reading for me?
    Thank you
    Charlie

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    1. #1 - I'd consult with a detailed anatomy/kinematics book to figure out where muscles are located and what motion they control.
      #2 - The sensors are sensitive to detect small muscle groups as well. Customers have used them to create virtual keyboards with individual fingers.
      #3 - This isn't our area of expertise so I'd suggest contacting a prosthetician

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  18. Hello, I'm using this Muscle sensor V3 in a Arduino-based project, which involves activates the movement of servos, upon receiving a signal from the EMG sensors.

    Since I'm relatively new to this, how exactly does the Arduino process the EMG signals as? And how does that show on the Arduino code? I've read all the guides on this page and I'm still a little confused.

    Also, since this is a product which is meant to be portable, is it possible to wire the +V's, GND, and -V's to the SAME battery box (in this case, a battery box which encases FIVE AA batterys, all at 1.5V, which adds up to 7.5V)? I'm asking this because the manual says I need +9V and -9V.

    Thanks.
    - Ivan

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    1. Hi Ivan, I'd suggest you make a post on Arduino's forum since this is more of an Arduino specific question. They have an amazing community on their forums and will be better suited to answer those questions.

      As for the battery, the manual actually states the minimum required voltage is +/-3.5V not +/-9V. We use the 9V setup simply as an easy example to get people started. Back to your question... you can use a single battery to power the sensor if the battery voltage is at least 7V. You would need to use a voltage divider to create a virtual ground in the middle of the battery voltage. Then use this virtual ground as the GND for the sensor, the battery - terminal for the -Vs and the + terminal for +Vs.

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  19. can ecg electrodes be used instead of these electrodes given with the kit?????

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    1. Most standard EMG and ECG electrodes with snap connectors can be used with the sensor. The electrodes given with the kit are just sample electrodes and are not meant to be used more then once.

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  20. Is the sensor V3 the only thing I need to purchase to begin training specific muscles? I have read through this website thoroughly and I am still somewhat confused on what I need to get started. Thank you. From, A Beginner

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    1. Hi Kimberly, I'd suggest reading through our User's Manual (https://docs.google.com/file/d/0B8Wy2qiwirwyNFV1dlA2T1JVZFU/edit?usp=sharing). I'm not sure what you mean exactly by 'begin training specific muscles'. A simple way to think of our sensor is to think of it as any traditional sensor (e.g. temperature, pressure, accelerometer). You need something to read the sensor for it to be useful. There are many ways to read a sensor (e.g. microcontroller, oscilloscope, volt meter, etc) and what will work best really depends on your application.

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  21. Hi, I am interested in buying your board but will it measure the thumb movements if I place the electrodes on the thenar muscle of the hand. I live in Canada so not sure regarding the procedure to order this from Canada.
    Thanks.

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    1. The sensor doesn't measure movements. You can have muscle activity without any joint movement (isometric contraction). Since you live in Canada, you'll need to place your order through one of our distributors (see link above).

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  22. Hi! Can i use this sensor for a FPGA instead of an arduino? And how long do you ship it to the philippines? Thanks

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    1. As long as it can take analog signals as an input. We do not ship outside the US. I would suggest purchasing through one of our distributors.

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  23. What are the specs of the 1u tant caps at VS?

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    1. http://www.digikey.com/product-detail/en/TAJR105K010RNJ/478-3278-1-ND/930070

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  24. hello i am going to be using these sensors in a university project i am making, but my game will have 4 buttons and i was thinking of having them set up as follow run left - tense left bicep , run right - tense right bicep, jump - clench right fist/tense forearm, fire - clench left fist/tense left forearm ,will this be possible with sensors on each arm, i will also be aiming to do this with the reusable fabrics aswell?? you help would be greatly appreciated, thank you

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    1. Yes we do this in our video game controller tutorial. http://www.instructables.com/id/USB-Biofeedback-Game-Controller/

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  25. what are the upper and lower cutoff frequencies of filter used in sensor???

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  26. hi everyone!

    I got a strange problem. When i'm providi voltage to the muscle sensor using voltage generator, i'm able to get the proper output.
    But, when i'm using batteries(philips 9V) instead of voltage generator i'm not able to get the proper output. So i tested weather am i providing the right voltage or not.. when i checked using multi meter i noticed the voltages are +9v and -9v. After giving the battery connections to the muscle sensor as mentioned in the user manual, interestingly i've noticed that all the voltage from one of the battery is drained and i really don't know what was happened. I tried the same thing with 2 more new batteries and again the same thing happened.

    Someone please let me know what's the problem was.

    Thanks in advance.

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    1. Sounds like you have the batteries wired wrong. The positive terminal of battery 2 should be connected to the negative terminal of battery 1.

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  27. Hello,
    i apparently connected everything as per your guideline, however i always get values ranging from 75 to 100, regardless of the condition of the muscle.

    Any hint?

    Thanks

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    1. Please send us an email (support@advancer.co) for technical support.

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  28. hello! since i am new so i have a question regarding the fact that how can i connect the sig and gnd muscle sensor to an oscilloscope?

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    1. Hi champ, You just need to connect the oscope probe to the SIG pin and the oscope ground to the GND pin.

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    2. So sir you mean to say that the (input) BNC cable should be connected to the SIG wire and 30pF ground (signed) jack to the GND of muscle sensor. ia m asking this because there are two jacks in oscope which says "input" and on the other there is a ground sign with 30pF printed on it.

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    3. Is this what your probe looks like? http://www.gabotronics.com/components/com_virtuemart/shop_image/product/Oscilloscope_Pro_4d7b2c7269f62.jpg

      The black aligator clip is the ground I am refering to.

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    4. No mine is little bit different it has one black aligator clip as shown in the image and the other is red aligator clip. so what you mean is that i have to the red one which i have to the SIG and the BNC cable to the input?

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    5. I don't understand what you mean when you say BNC to the input. Are you asking if should you connect the probe BNC connector to the oscope?

      Does yours look like this? http://m4.sourcingmap.com/photo_new/20080319/g/ux_a08031900ux0030_ux_g03.jpg

      If so, the red should go to SIG and black should go to GND.

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    6. exctly sir! mine looks the same.what i mean is this whole cable should be connected to the "input"jack of the oscilloscope?

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    7. You might want to contact your oscope manufacturer if you have questions on how to set it up. But most likely the answer to your question is yes. Hard to tell though cause you haven't said what kind of oscope you are using and I'm not that familiar with oscopes other than the few I've used.

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    8. Thank you sir!it was a great help.

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  29. Hi there... May I know how was the power consumption for the sensor,as it was using two 9v battery. How many time the electrode can use in measurement ?

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    1. The electrodes are single use electrodes. The power consumption is less than 100mAh.

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    2. What do you mean by the power consumption is less than 100mAh? Do you mean it drains 100mA from the +9V and 100mA from the other -9V battery?
      I am trying to build a dual power supply from a single battery. Most step up circuits can only souce minimal currents (10-20mA) would this be enough to power the sensor +5V@15mA and -5V@15mA? Whats the actual power consumption of the sensor? Does it vary with the supply voltage?
      Thank you!

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  30. Hi. Could you explain me why low-pass filter's cutoff frequency is 2 Hz? Low-pass filter passes signals with a frequency lower than this. And why high-pass filter passes signals above 106 Hz? Shouldn't it be the other way around? What you meant to achieve is to pass signal in the range of 2-106 Hz? Or am I wrong? Thank you in advance for explaining.

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    1. Hi, look up above for the comment thread started on July 3, 2013 at 10:41 PM. It explains the 2Hz low-pass filter. There's also an explanation in the User's Manual.

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    2. Ok, now I get it. What about HP filter? It passes signals above 106 Hz? So the range would be about 106-500?

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    3. That's not a HP. It's a coupling capacitor. It removes any inherent DC bias in the signal coming out of the instrumentation op amp. DC bias is can be cause by many factors. http://www.analog.com/static/imported-files/tech_docs/ECG-EEG-EMG_FINAL.pdf

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    4. Thank you for quick and clear answer!

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  31. Is the sensor output a pure dc signal?

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    1. Not sure what you are asking. DC or "direct current" doesn't really make sense in this context. However, the output is an analog signal if that is what you are asking about.

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  32. Hi, please can you use NI ELVIS II board as your microcontroller instead of Arduino?

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    1. Our sensor can be used by most development boards.

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  33. Hi, I have connected the sensors as per specification using 9V batteries. It worked the first time giving arbitrary sensors readings. But the second time I go to measure it, the readings are zero and when i pull the sensor reading wire from the arduino, it goes to 1023. Is there any problem with the breakout board, I am pretty sure I havent reversed the polarity nor short circuited the board. Also, are the electrodes with the blue black and red wires for one time use or multiple times?

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  34. Is there a difference in the output signal of this sensor and the MyoWare? (Not raw, but the SIG pin in both sensors)

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