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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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2answers
49 views

Hand contacting op amp photodiode circuit causes interference - what ist the physic behind it?

I am new to analogue electronics and I am still learning about op-amps. I use the most common circuit for amplifying a photodiode's signal to measure it with an ADC: Amplification gain is 1M, the ...
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0answers
82 views

Whenever two system or sources are coupled they should have same current sink or common reference point (say ground). How to realize this in ECG?

Electrode (Ag-AgCl) are placed at different part and directly fed to positive and negative input of differential amplifier. How can we realize human body and amplifying system have same current sink ...
14
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4answers
2k views

Why would you put your input amplifier in front of your filtering for an ECG signal?

In this article at eetimes.com they show the signal chain for measuring an ECG. The raw signal of an ECG contains noise and offsets at least a magnitude larger than the real signal. (Some few mV ...
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1answer
61 views

Modify the AD8232 chip configuration to use only LEFT and RIGHT arm in steel leads configuration

I am an industrial designer (little experience with electronics) trying to modify one of the AD8232 chip configurations. The AD8232 is a Single-Lead, Heart Rate Monitor Front End. In the datasheet, ...
0
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0answers
60 views

EMG signal from MyoWare board - sudden increase in output voltage

I am using the MyoWare muscle sensor from Advancer Technologies (this one) to obtain EMG signals from my forearm. I want to use it in a project where I will be checking if the muscle is flexed or not. ...
6
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5answers
877 views

Circuit for small level voltage detection (microvolts)

I have been working on a project lately which help in the detection myogenic potentials (of the levels of micro-volts). After studying from several places, I finalized the following test circuit. The ...
2
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1answer
56 views

Direct signal injection from function generator for EEG BCI calibration

I have seen several topics related to calibration of BCI and most of them use a "head phantom". But I want to know, is it possible to test the openBCI hardware directly using function generator? And I ...
1
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1answer
93 views

Can ECG electrodes be used for EEG detection?

Im having financial limitation for purchasing EEG monitoring modules or electrodes. But so is not the case for ECG. I am doubtful whether I can use ECG electrodes for EEG since brainwaves are in the ...
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2answers
93 views

Are electrodes mostly homogeneous or are there variations by usage, such as EEG vs EKG/ECG?

Are electrodes mostly homogeneous or are there variations by usage? My main usage is EEG. I have some interests in other areas and see similar electrodes sold for less money when marketed for ...
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2answers
229 views

Why is bipolar EMG better than monopolar at reducing (common mode) noises?

As defined in this post, the monopolar EMG can reduce the common mode noise by taking the difference of the two inputs, i.e. EMG_mono = k * (V1 - V2). And, for bipolar mode,EMG_bi = k3 * [k1 * (V1 - ...
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1answer
46 views

Testing the integrity of cable shielding for suitability

I am currently working with an ECG cable, is there a way for me to test the integrity of the shielding of the cable without using it directly on an ECG monitor to check for interference.
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1answer
110 views

Is it possible to make a lightbulb light up by wetting your hands? [closed]

I was recently watching an Electroboom video on free energy devices, but my question is not about any of that stuff. Here's the video. At about 5:50 he claims and seemingly shows that he can light up ...
0
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1answer
804 views

Is there any difference between AD620 vs INA128?

I'm trying to make an EMG sensor. I've found some tutorials, for example, DIY muscle sensor/EMG circuit for a microcontroller, but my main question is can I make an EMG sensor using AD620 instead of ...
0
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2answers
146 views

Recording of sensory nerve evoked potential generated through skin-receptors [closed]

If we touch / give pressure to a skin, there are many mechano-receptors like meissner/pacinian corpuscles that produce action potential in neurons. I am in a need to detect those action potentials ...
2
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2answers
115 views

Does anyone have advice on homemade EKG/ECG leads?

I'm not sure this is where it should be posted, so apologies in advance, but I'm working with an Arduino and Sparkfun's heart rate monitor AD8232 (https://www.sparkfun.com/products/12650) to gather ...
0
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0answers
62 views

why is ad620 output signal disappearing after connecting the right leg drive to the human body?

I am building an ECG sensor based on the AD620 instrumentation amplifier. The circuit is amplifying minute(50uV) signals from the signal generator perfectly. The total gain of the circuit is around ...
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1answer
301 views

How to Calculate the Impedance of the Capacitor T network?

I guess Capacitor T network used in the schematics is for Impedance matching, if yes how to calculate the impedance of the same circuit?
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0answers
58 views

why is the gain of ad620 not responding to the change in( Rg), the gain resistor?

I am building an ECG sensor based on the AD620 instrumentation amplifier.For the purposes of testing , i have built a simple AD620 circuit with pin 2(-) and pin 3(+) connected to a 2.82mV(peak to peak)...
1
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1answer
181 views

Using AD5933 with an external amplification to measure changes of permittivity

I'm going to try and explain my problem statement first and then explain my solution and then ask for suggestions. So, my problem statement is this: To determine changes in permittivity from a ...
0
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2answers
88 views

Help with identifying a transfer function - with neuroscience application

This is a question for you electrical network engineers. The problem has arisen in a neuroscience study I am working on, but I hope to be able to glean some insight from other domains that deal with ...
0
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2answers
214 views

Can Texas Instrument's INA332 really be used for EEG?

On TI's datasheet, it specifically lists EEG as one of INA332's potential uses. EEGs are microvolt level signals, and the INA332 has input offsets of +/- 2 milliVolts. 73db CMRR is quite low, but ...
0
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1answer
66 views

University Project - Common Mode feedback in EEG systems

Basically EEG signals (potential from brain) contain 'noise' due to EMG signals (potential from muscles). I was thinking of using the EMG as a common mode feedback prior to the amplification of the ...
1
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1answer
58 views

Patient protection in a biopotential amplifier

My question is in regards to biopotential amplifiers, more specifically an instrumentation amplifier as part of an ECG. I know that IEC60601 states that a paitent must be limited to 50uA under fault ...
1
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1answer
175 views

Signal Processing of a raw EMG signal

I am a student. I acquired EMG signal (sampled at 1KHz) by using dry electrodes. At first, it was all noisy. I then applied a Notch Filter (@50Hz) and the signal looks better but still not great. Any ...
4
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2answers
1k views

ECG circuit Pre amplifier

I am in the process of designing an ECG circuit to detect heartbeat abnormalities. I have two question regarding the AD8220 datasheet: What is the function of the 2.2pF, 10pF capacitor, 10k, 15k ...
5
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4answers
1k views

why is a GROUND electrode needed with a referential amplifier?

Physiological amplifiers seem to often (always?) have both ground (G) and reference (R) electrodes along with one or more active (A) electrodes. Typical voltage at an active site is determined AFAIK ...
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0answers
40 views

Understanding what Electrode Impedance values mean on Spec sheet

I want to understand what the electrode impedance values given on spec sheet mean. Just looking to gain a general understanding and what voltages/ currents I can or cannot use. The electrodes are used ...
0
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0answers
113 views

Voltage drops across a Human Body (Set gain of InAmp)

I'm developing an application that sends an electrical signal to the human body. It is a bioimpedance system. This signal has approximately 3.2Vpp ranging between + 1.6V and -1.6V, at a frequency ...
1
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1answer
139 views

Do certain types of electrodes work better than others in an area with hair?

In selecting components for an EEG development kit, I'm wondering if certain types of electrodes capture signals better in the presence of (a small amount of) head hair? For instance options include: ...
0
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0answers
56 views

How CMOS transistors might be used as a capacitive sensor for biopotential?

I was wondering how CMOS-based capacitive electrodes might be designed (e.g. in this article I stumbled on). It seems to me, that it would make sense to capacitively couple the input of the transistor ...
-3
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1answer
190 views

Can we have the action potential an AC current [closed]

as well known brain are connected to our body by neuronal cells. it transmits and receives its data by action potential during neuronal cells. i wonder if any one can explain to me the properties of ...
0
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2answers
664 views

EMG, Muscle Sensor Arduino - Troubleshooting [closed]

I've been testing the EMG sensor below: http://www.ebay.com/itm/Muscle-Sensor-EKG-EMG-Developemt-Electronics-Module-Interface-Kit-For-Arduino/351850511727?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=...
0
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2answers
263 views

Switching input to instrumental amplifier with an analog mux (ECG, EEG)

I'm trying to find a cost effective method of taking samples of electrical signals of the body (and potentially plants). Can you have one high precision instrumental amplifier and then use an analog ...
1
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1answer
150 views

How to test an EEG?

Apologies out of the gate here as I'm a CS person with not a huge amount of experience in electronics, so this might be a pretty basic question. I've built basic EEGs before, basically electrodes ...
0
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1answer
63 views

Transimpedance amplifier with biopotentials

I have a PPG sensor to be specific the sensor is called " easy pulse finger sensor " which is a ( phototransisitor), can it be connected to a transimpedance amplifier ( current to voltage converter)?!...
0
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1answer
252 views

50 Hz noise only in chest leads of 12 lead ECG

I am implementing a 12-lead ECG signal conditioning circuit. With the current design the bipolar leads (lead-I and II) are of sufficient quality with no visible 50 Hz noise. However, the unipolar ...
0
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1answer
300 views

Can you measure the voltage produced in the heart using an oscilloscope or multimeter

Can you measure a PQRST wave using a multimeter or oscilloscope, it you can will two leads be enough and why are 12 leads standard tor ECG monitoring?
0
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2answers
715 views

Low-power Li-Ion Battery Charging

I am looking for the cheapest, smallest way of charging a 50-100 mAh 3.7V Li-Ion battery through micro USB. Fast-charging is not necessary, especially if it would cause an increase in price or size. ...
-1
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2answers
508 views

EEG signal aquisition help

I Have designed a circuit to acquire the EEG signal from electrode within 0-20 microvolt. My design consists of AD620 (gain = 2), -> LPF (4th order G=2.515, Fc= 0-40Hz),-> HPF (4th order G=2.515, Fc = ...
0
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0answers
818 views

EMG amplifier using LM358

I came up with the following simple schematic in order to amplify the EMG signal and feed it to an arduino: simulate this circuit – Schematic created using CircuitLab The problem is that I ...
-2
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1answer
103 views

How to determine voltage using difference amplifier?

I made an EMG sensor from a tutorial found on the internet with the amplifiers INA106 and TL072 and another ...
0
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1answer
47 views

Safety considerations in Android Wear products using high resistance electrodes

I am wondering how wristlet devices can safely measure a person's heartbeat without risk of electric shock. It seems everywhere I read, the threat of static discharge would be far greater with an ...
2
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1answer
338 views

Building an instrumentation amplifier

I am trying to develop a system for bioimpedance measurement. I will use a frequency equivalent to 50KHz, using this project to support me. The project uses an instrumentation amplifier. In my city ...
0
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1answer
564 views

How to get raw emg signal without offset

i try to build emg sensor + arduino from diy found on internet. every things work fine, but i want only raw signal for some bigger project not rectify. i do circuit as below and signal looks like ...
1
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1answer
598 views

Plessey Epic Sensors For Non Contact ECG

This may not be the right place to ask this question. If this is the case, please suggest an alternative and I will gladly move this question to a suitable forum. I am trying to wirelessly capture an ...
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2answers
158 views

Will massage electrodes work for eeg?

Have anyone tried to use massage electrodes for eeg? I believe as they conduct high charges probably using inexpensive metals they are not suitable for measuring tiny voltage changes but I'm not sure.
0
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1answer
2k views

2 Lead ECG without RLD AD8232

I have got the SparkFun kit with the AD8232. The schematic is: I wish to use only 2 leads; how do I ground the third lead RLD? I'm collecting the signal from the hands. The datasheet only gives ...
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3answers
517 views

4017 Counter LED Shuffle By Touch

Hi all, I found the following circuit on the internet and made it on the back of a business card as a fun project. The idea is that you ask a question, touch the naked wire, the lights shuffle and ...
1
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2answers
542 views

Notch filter ECG

I am using the Sparkfun Development kit based on AD8232 for acquiring the ECG signal from the body. Sparkfun Kit. Now I am getting a perfect ECG signal when I turn off all the power in the house and ...
0
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1answer
121 views

INA155 reference pin not working

To test the INA 155 I gave a sine wave of amplitude 0.2 V p-p 100Hz. It was operated at 5 V single supply. The reference pin was connected to 2.5 V from an op amp buffer. There seems to be no offset ...