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Questions tagged [biopotential]

Instrumentation related to the measurement of bioelectric phenomena from the living system, such as ECG, EEG, EMG, and galvanic skin response.

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0answers
1k views

How to find the resonant frequency of a human body?

I've read that the human body has resonant frequencies somewhere around 50MHz. I also think it would be interesting to look for values in other ranges like 10-100 kHz. I'm wondering how to build a ...
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1answer
689 views

Is it possible to measure Spinal Cord electrical activity over skin? [closed]

sorry if this is not the right place to ask this question. I'd like to know the possibility and reliability of measuring electrical activity of spinal cord (specially the cervical region) if it's ...
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2answers
119 views

Circuit Testing, Verification & Certification Standards for Biomedical Devices

Please note: I would have posted this question on HealthIT.SE but they are apparently now closed for business, and I believe this site is the next most appropriate place to ask this. I believe this ...
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1answer
1k views

gain with no side effects

I want to see a signal (5-25 microvolts | 1-35HZ) on my computer.but I dont know electronics so I just have one question: I need to amplify THE signal to reach <...
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1answer
965 views

Why there are minimum three electrodes used in ECG, EMG measurements?

My question is related to the number of electrodes used in ECG/EMG kind of signals. I know that voltage measurement is a potential difference measurement. I understand the concept of signal and ...
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2answers
2k views

How is this EEG circuit amplifying and filtering input correctly?

Several weeks ago I posted several|questions about a DIY EEG reader that I found on Instructables. To my surprise, it appears to actually be a fairly well-designed circuit. The main stages of this ...
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1answer
543 views

Heartrate measuring using capacitive touch sensor

I am new here, and I hope someone could help me. So I've read in the datasheet of the capacitive touch sensor ATMEL42QT1011 that we could use it as a heart rate sensor.But what I don't understand is ...
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2answers
242 views

Can I realize displaying action potential of a plant in a very minimal setup? [closed]

I would like to show an experiment for kids on the Science day this April in our institute. It is inspired from this Backyard Brain's experiment. This experiment shows the action potential captured ...
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1answer
194 views

How to ground the below circuit when I use USB?

I am constructing the circuit given below: The problem, however, is that when I connect the electrodes to my skin, I get a mild shock. I am powering the Arduino using an USB cable. I connected the ...
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2answers
533 views

Is there an advantage to process EEG data as analog (vs digitized) signals?

Please note: Although this question mentions an electronic circuit depicting an EEG, I believe this is purely a bio-electrical question that is appropriate for this site, and should be answered by any ...
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2answers
232 views

To what extent does an ADC solve noise along an analog circuit?

Please note: Although this question involves EEG, I don't expect anyone here to be knowledgeable in this area! This is a simple electronics question! I'm trying to understand the circuitry devised in ...
4
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1answer
382 views

Questions about Dry EEG electrode interfacing circuit

I have finished reading a paper about developing an interfacing circuit for Dry EEG electrodes and there is a few points that I couldn't understand. To mask the diode’s parasitic capacitance and ...
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1answer
1k views

How does capacitive EEG electrodes measures EEG signals

I have read the following sentences from an article: The effect that there are also charge displacements on the body surface due to brain activity is used for the capacitive measurement of the ...
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1answer
1k views

How can I make an LED glow by touching it with my finger?

I can make an LED glow very dimly in all 4 following circuits. The voltage source in the circuits is the output of an AC to DC converter fed into a breadboard. Also, one end of the voltage source is ...
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1answer
2k views

ECG: gain of right leg drive?

I am trying to build a simple ECG circuit. I designed the circuit based on multiple ideas from the internet and the parts (INA118P) available. What I do not exactly understand is how much the gain of ...
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1answer
224 views

ECG cardiac monitoring [closed]

How is the signal observed from electrode and electrode impedance is affected if we clean one of the pair of Ag/AgCl cardiac electrode by scraping it with steel wool until it was shiny and bright
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1answer
1k views

Stop blinking LD1 on STM32F4 Discovery

I have a system I built using a ADS1263 32-bit ADC that is measuring tiny biopotentials without much amplification (for a variety of reasons not under discussion) -- one very low noise instrumentation ...
4
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1answer
2k views

Is it possible to measure the voltage produced in heart

I learnt from my high school biology that human heart will produce about 1mV from the sinoatrial node.(voltage will vary like the graph in ECG test).Is it possible to measure the voltage with any ...
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1answer
466 views

Homemade PC EKG circuit

About a week ago I had an idea to build a computer EKG using the computer's mic input as a signal input. One of the most complete tutorials I found on the internet was this one (that is applicable on ...
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1answer
252 views

Choosing opamp with sufficient output current for Voltage Reference with high impedance load

I am designing a differential sensor that will be placed on the skin to detect biopotentials. Two inputs are fed into an instrumentation amplifier that has a reference set at 1.5 volts (VREF15 in the ...
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2answers
83 views

How to Generate a Calibration Signal?

I'd like to generate an integrated calibration signal for a biopotential amplifier. I'd like to generate a 0.5mV square wave (within 5%) at 200Hz (give or take on the frequency). I'm thinking of ...
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2answers
1k views

What can ECG DC level be?

In ECG signal, to what DC level should i expect? Can it be 3V, at least from time to time? Alternatively, what would be decent input voltage range for the instrumental amplifier for ECG stage?
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3answers
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Amplify Microvolts up to Volts

I'm trying to create completely DIY EMG. As many of you may know, I will be dealing with microvolt inputs. I know that op amps amplify voltage, but I am wondering if I can somehow get a 1,000,000x ...
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1answer
1k views

AD5933 analogs for 4-terminal measurements

I'm going to do bioimpedance measurements, and it seems that AD5933 chip (http://www.analog.com/media/en/technical-documentation/data-sheets/AD5933.pdf) has many useful features for this. However, ...
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3answers
399 views

60Hz “click” or clipping noise when differential amplifier is surrounded by salt water

I am a graduate student attempting to take electrophysiology recordings from a lobster under water. In the current set up I am using, two differential amplifier boards are attached the the lobster's ...
3
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1answer
961 views

Bioelectrical Body Impedance Analysis?

On what principle Bioelectrical Body Impedance Analyzer works? I thought about this many times, and I wanted to know is there really a way to precisely measure all those body parameters with this ...
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1answer
710 views

How does the Bias Drive in TI ADS1299 help in noise reduction?

I'm bit of a noob in electronics so please pardon me if this question is too basic. I would like to clearly understand how the signal from the bias drive electrode can help in noise reduction, ...
2
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1answer
404 views

AD8222 single supply EMG

I am working with the AD8222 dual package instrumentation amplifier from Analog Devices. I want to build a compact EMG system so I am trying to use this chip since there are not a lot of dual IAs on ...
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2answers
396 views

Capacitive ECG electrodes and capacitor discharge

I am trying to make ecg electrodes with capacitive coupling. Since my capacitor is only about 10 pF at max and I have to have as low cut-off frequncy as possible, I came up with a circuit like this. ...
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1answer
240 views

Are Bioimpedance sensor different from Biopotentials sensors?

I am building an portable health device , for which i am want ECG , GSR etc. then i came across 2 terms Bioimpedance and Biopotentials. Are these two same. Also can any one say the applications of ...
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1answer
2k views

EEG amplifier circuit low and high pass filters. Oscillations, noise, etc

I designed a EEG amplifier circuit for for EEG signal amplification and filtering. Because I never had any experience in filters, It would be highly appreciated if someone could check my design. In ...
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1answer
640 views

How Simulate Right Leg Driver

I am having trouble simulating Right Leg Driver in an amplifying circuit of eeg signals. The schematic of the circuit: The instrumental amplifier circuit has a gain of about 2 and E1 have 10m ...
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2answers
1k views

EMG design help using AD8221 INAMP

I'm designing active electrodes for surface EMG, active electrodes being electrodes directly connected to a pre-amp and filtering stage on the measurement site. Im working with the AD8221 IN-AMP to ...
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2answers
1k views

How can EEG electrodes pick up EMG signals and still function?

EMG signal is the signal generated by muscle flex. EEG electrodes is the scalp potential generated by neuron firing. EEG is on the order of micro Volts whereas EMG is on the order of mili Volts, this ...
2
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2answers
417 views

Electronic sensor for monitoring photosynthesis

I have to develop a sensor that can detect photosynthesis. So when the plants are exposed to sun I should get an indication that photosynthesis is happening inside the leaves. I found many products ...
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1answer
296 views

Arduino ECG sputtering out totally random values

Hello StackExchange community, I have encountered a problem in my ECG/EKG design. I am trying to create the ECG using Arduino as a microcontroller to send/retrieve heart rate measurements via ...
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1answer
2k views

Simple circuit with operational amplifier (intended to be ECG) not picking up actual readings, only noise

I have a major problem. A couple days ago, I ran into an issue with my circuit. The problem is that I can only get noise from my ECG, not actual readings. I'm using opamp LM358, not opamp OP37 like ...
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1answer
2k views

Arduino - Cannot get ECG readings from heart, but I do when I poke at the leads

I have a minor issue with my ECG. When I poke at the leads, I get a reading. But when I hold the leads or place it near my heart, I don't get anything. I'm pretty sure this is hardware related, but ...
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2answers
1k views

Does an electrocardiography recorder put current/voltage on its electrodes?

(I do hope my question is not off-topic) Currently learning about ECG recorders (Our 7-months old daughter has to have one during her sleep), I wonder whether this is a pure "passive" measuring ...
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4answers
12k views

Optical heart rate sensor vs bioimpedance sensor?

I didn't know a better place to ask this, so here it goes. For activity trackers, Fitbit has the Charge HR with an optical heart rate monitor, while Jawbone has the UP3 with a bioimpedance sensor for ...
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1answer
644 views

What does the feedback capacitor do in Right-Leg-Driver?

It so happens I have seen some people mention about connect a feedback capacitor across the opamp for RLD would improve something better. Can someone capable to explain about the use of the ...
8
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1answer
3k views

Patient protection resistors in the biopotential amplifiers

In biopotential amplifiers like ECG amplifier, I often see protection resistors (around 100kohm) between electrode and the input of instrumentation amplifier or ECG amplifiers like ADS1298. I ...
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1answer
350 views

Measuring pulse using an EMG device

For another project I once bought the following EMG sensor kit: https://www.sparkfun.com/products/11776 Now, I would like to know if it is possible to measure the heart pulse using that EMG sensor ...
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2answers
197 views

Biopotential measurement circuit

I have read the following paper (the link at the end), and I have not understand the schematic, which is included in the picture below. To be more specific, there is a feedback integrator, denoted by ...
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5answers
1k views

User safety for battery powerd device against misuse of power supply

I want to design a safety circuit for a battery powered device which measures human body impedance. It is intended to be powered only by an external battery pack (5V) via a USB cable. But I want to ...
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3answers
2k views

How to set up an experiement to measure SNR for an EEG amplifier?

I have built an EEG amplifier with gain of 2000 and bandwith at 1~40Hz. I use an Instrument Amplifier for pre-Amp and a non-inverting opamp as post-amp and finally bandlimit at 40Hz using a 4th-order ...
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2answers
511 views

interfacing circuit for EEG signal

I was looking to an interfacing circuit for EEG signal , and i get this schematic , which is shown below , my question is , what is the point pov , it's said to be ...
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3answers
495 views

Wireless EEG electrode design

Currently, all 'wireless' EEG systems acquire signals from electrodes which are wired to an amplifier, a filter, a digitizer and then finally a wireless module. I want to design a system that's ...
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2answers
2k views

How to measure microvolts of biopotential with Arduino?

I'm new to electronics, so don't judge me harshly. I need to measure the biopotential of a human. I will place special electrodes on the skin, and need to measure the voltage on it. Ordinarily, the ...
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3answers
2k views

sensors for detecting breathing movements

I am looking to find out what sensors can i use in my wearable, to detect if someone is breathing.. we would also like to find out their breathing pattern if it is long deep breath or shallow breath.