Cyton, questions on 5 GPIO pins, 3 of which can be Analog

Sotiris1Sotiris1 greece
edited July 5 in Cyton

I am currently an undergraduate student at the Democritus University of Thrace in Greece performing my dissertation thesis in the field of biomedicine. For this purpose, my colleagues and I, would like to develop a system of wearable sensors that will enable the continuous monitoring of vital biomedical parameters such as the body temperature, the blood pressure, the saturation of oxygen in blood, the hearth rhythm, as well as the electrocardiogram.

I would like to get the Cyton Biosensing Board (8-channels) from your company and I have some questions in this: Specifically, the technical characteristics of this evaluation board state that it has: 5 GPIO pins, 3 of which can be Analog. For this feature I would like to ask you what is its usefulness and if I could for example connect to these GPIO pins an analog or digital signal and ''see'' these sensors through the Cyton Biosensing Board ??

Comments

  • wjcroftwjcroft Mount Shasta, CA

    Hi, Sotiris,

    The Cyton data stream contains the 8 'normal' channels, used for EEG, ECG, EMG, etc. Then it has 3 additional channels, called 'Aux', Auxiliary channels. These are typically used for external trigger synchronization, or lower resolution analog to digital conversion. The 8 channels are 24 bit resolution. The 3 Aux channels are limited by the resolution of the ADC built into the PIC32 processor, which is 10 bit resolution in the range of 0V to 3.3V.

    Normally the Aux channels default to read the x,y,z of the accelerometer. But they can be switched into reading GPIO pins, in either 'digital' or 'analog' mode (not both).

    https://docs.openbci.com/docs/02Cyton/CytonDataFormat
    https://docs.openbci.com/docs/02Cyton/CytonSDK#board-mode

    Regards, William

  • Sotiris1Sotiris1 greece

    So to see if I got it right, can I use these auxiliary pins / GPIO to connect analog or digital sensors (not at the same time) ???

    If not, is there a development board from your company that supports all these EEG E C G measurements and at the same time has ports / GPIOS for connecting analog or digital sensors to receive other parameters ??

  • Sotiris1Sotiris1 greece

    Thank you very much for your speedy response !!

  • wjcroftwjcroft Mount Shasta, CA

    So to see if I got it right, can I use these auxiliary pins / GPIO to connect analog or digital sensors (not at the same time) ???

    As mentioned, the default for the three Aux channels is the accelerometer. They can be switched instead to sample the GPIO pins, and when that is done all three pins are either read digitally or in analog mode.

    Normally the EEG, ECG, EMG measurements occur on the primary 8 channels. The 3 extra Aux channels are typically used for gathering time sync information that is recorded simultaneously with the 8 channel EEG. In analog mode, the Aux channels are not that great for biosignals, as the range is only 0V to 3.3V. These Aux channels cannot record EEG, which is in microvolts. Similarly ECG is in the millivolt range and thus also not very usable with such a low resolution, non-amplifed ADC.

  • Sotiris1Sotiris1 greece

    Thank you very much for speedy response.

    I have another question that I asked you before,is there a development board from your company that supports all these EEG ECG measurements and at the same time has ports / GPIOS for connecting analog or digital sensors to receive other parameters such as SP02, Glucose, and BP ??

    Does your company have analog or digital sensors that I can supply ??

  • wjcroftwjcroft Mount Shasta, CA

    I think you are referring to this previous thread,

    https://openbci.com/forum/index.php?p=/discussion/2998/types-of-eeg-ecg-electrodes#latest

    On which I recommended the EmotiBit as a possible aid that will collect SPO2, heart rate, HRV, GSR/EDA, etc.

    https://www.emotibit.com/

    Glucose and blood pressure are not as easy to measure with small, continuous monitoring wearables. But there are some newer solutions showing up, such as,

    https://www.dexcom.com/

    Many articles claim wearable blood pressure is not quite ready yet.

    https://www.google.com/search?q=blood+pressure+wearable
    https://www.consumerreports.org/blood-pressure-monitors/measuring-blood-pressure-with-a-wearable-device/

    ...and at the same time has ports / GPIOS for connecting analog or digital sensors to receive other parameters such as SP02, Glucose, and BP ?? Does your company have analog or digital sensors that I can supply ?? ...

    OpenBCI boards are geared to EEG, ECG, EMG, EOG, etc. If you need other biometrics, the best solution is to just use the appropriate wearables. Their data will come in on a separate Bluetooth or Wifi data stream. Your software that collects data streams will then be able to merge the streams as needed. You are unlikely to find a single device that does everything or connects to everything.

    William

  • Sotiris1Sotiris1 greece

    I would just like, in the context of the project I have undertaken, to procure a development board for the connection of sensors that will measure various parameters. Ideally I should build a board just because of the time limit and because I am a beginner in designing such a system and board, I do not choose this way.
    For this reason I asked you if you know of any development board that has the pins connections ready?

    Kinds Regards Sotiris

  • wjcroftwjcroft Mount Shasta, CA

    OpenBCI boards are geared to EEG, ECG, EMG, EOG, etc. If you need other biometrics, the best solution is to just use the appropriate wearables. Their data will come in on a separate Bluetooth or Wifi data stream. Your software that collects data streams will then be able to merge the streams as needed. You are unlikely to find a single device that does everything or connects to everything.

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