Android WiPy2.0 Bluetooth connectivity?



  • Hi,
    I want to try and create a wearable medical imaging device for a Uni project. I want to gather voltage data from electrodes (process it via 8 channel ADC) and sent it to my smartphone using Bluetooth. Will this be possible using the WiPy 2.0? I have read that it doesnt support pairing, but someone mentioned in another thread that it is still possible to exchange data between the two, even without pairing. If the WiPy 2.0 is unsuitable for this, could you propose any other alternatives?

    WiPy 2.0 is very appealing cause of powerful processor, 8 channel ADC, and DAC.

    PS: Does anyone know the sampling rate of the ADC and DAC maximum freq on the wipy 2.0? I haven't found this on any datasheet.

    Thanks,
    Panos



  • @panos29 It's more about the ADC range, which is about 0.07 - 1.1V for the reading between 0 and 4096. I assume you would always need some kind of pre-amplifier/buffer, at least to protect the esp32 against damage,, and if you do not need to take values at hight speed, you can always use averaging to reduce the noise.
    The esp32 chip is told to have a built-in preamplifier, but that is not supported by Micropython, and I do not know whether it works.



  • @robert-hh Thanks for the reply. About the ADCs, will I be able to get decent measurements using the WiPy ADCs? The project isn't really intended for professional use, so as long as I get the measurements and a more or less correct output on my android phone, I'll be happy.
    Because I read that pycom doesn't support pairing, will I be using "GATT" to send data to my phone?



  • @panos29 Calling dac.write() to set a value takes about 33 µs, call adc() to get a value takes about 38 µs.
    P.S.: If you require a high quality ADC, do NOT use the internal ones. They are quite noisy show some non-linearity. For you application, the noise may be the bigger problem. And obviously, for medical applications you need an analog input stage for amplification and filtering.


 

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