Non Contact ECG recording

Discussion in 'Digital Circuit Design' started by sa bassesse, Aug 18, 2017.

  1. sa bassesse

    Thread Starter New Member

    Sep 7, 2008
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    Plessey Semiconductor has developed an Electric Potential Integrated Circuit Sensors that are touted capable to "easily and discretely incorporated inside the vehicle seatbacks to access the necessary biometric signals and provide earlier warning of drowsiness or health issues than systems based on eye or head movement". The company also says that their sensor can capture the person's electrocardiogram (ECG) and sense the electrical impulses of the heart without direct skin contact and can return an accurate R peak signal from the users ECG which can be used to calculate HRV. This is a very impressive breakthrough. I have tried to use the sensors but I cannot get them to work as advertised. In short, I cannot get the any ECG signal at all. I was wondering if there is anyone on this forum who has ever used the sensor and if he/she is willing to share his/her experience using the sensor.
     
  2. RichardO

    Senior Member

    May 4, 2013
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    What is the exact part yu are trying to use? Please supply your circuit and the data sheet for better answers.
     
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  3. BR-549

    Distinguished Member

    Sep 22, 2013
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    I have no experience in the directed question. But many of the new micro-chips.....are set up for cap I/O. And have all the needed software libraries. I would study this route. We will probably see a lot more of this. Possibly for human detection. It's so cheap to do now.
     
  4. Raymond Genovese

    Active Member

    Mar 5, 2016
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    I looked at the link and then went to the EPIC sensor link. Clearly, it operates in contact and non-contact mode. ECG, EEG and the like are all in contact mode. In non-contact mode, they are basically movement/proximity sensors - "measures disruption in the electric field caused by human body movement enabling"

    The WARDEN device is where you see the quote "The company also says that their sensor can capture the person's electrocardiogram (ECG) and sense the electrical impulses of the heart without direct skin contact and can return an accurate R peak signal from the users ECG which can be used to calculate HRV."

    I agree that it sounds very impressive, but note that those "seat covers" look like an array of sensors and there may be others that are used as well. Not saying it does not work or that it is impossible to get an estimate of the single measure of R peak without the usual contact electrodes, but I don't interpret that advert as a single sensor that you can simply point at the person and get an ecg. I also browsed a data sheet or two and didn't see anything that would convince me otherwise.

    Still, it is very interesting and I would also like to know what sensor you are using, what amplifier, software etc.. Please let us know.
     
  5. sa bassesse

    Thread Starter New Member

    Sep 7, 2008
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    Thanks for your reply. I am using PS25255 EPIC sensor (data sheet is attached). I tried replicate the circuit in the datasheet but I get a square wave output instead.
     
  6. sa bassesse

    Thread Starter New Member

    Sep 7, 2008
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    Thanks a lot for your thorough reply and for checking out the datasheet yourself. Like you said, the company's claims are impressive. If the sensor does exactly what it is touted to do, this would be a breakthrough, especially in the medical engineering domain. However, the sensor has been around since 2011 and I have yet to hear about a product based on their sensors. Given the proliferation personal medical/fitness devices, I would expect these sensors to be widely used. Also, the lack of any support whatsoever for the sensor leads me to belive that the product is probably overhyped. Still, this is a great start. I was hoping that someone here has used the sensor and would provide his impression of the sensor.
     
  7. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    The device is essentially an electric-field-change sensor. I'd be very surprised if a gizmo using it could reliably detect, in a non-contact way, the tiny ECG voltages through layers of clothing in the presence of electrostatic fields generated by clothing movement or the overwhelming electrical noise found in a typical automotive environment. Some serious signal conditioning would be required.
     
  8. GopherT

    AAC Fanatic!

    Nov 23, 2012
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    Reduce your gain
     
  9. Raymond Genovese

    Active Member

    Mar 5, 2016
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    Sorry, I have not used the sensor. @RK37 wrote a brief article about the MAX30004. I wonder if that would be useful for this kind of sensor?
     
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