Hello.
I designed my own PCB to host an AFE4400 and a microcontroller, in order to implement a prototype with heart beat sensing capability. The photodiode and photodetector are the same as in TIDA-00011.
I have already exaustively tried several different Rx and Tx configurations for AFE4400, but I still cannot see the expected periodic signals at the registers 2Ah to 2Fh, which would allow me to get the heart rate.
Everything I get is a very noisy periodic signal with itsfundamental frequency around 5 Hz (something very fast to be a heart beat). I measure the time each time these registers are read.
Both the noise and the periodic signal are present when touching or not the photodiode/photodetector pair, but in the first case the amplitude of the 5 Hz signal increases. I also tried to unplug my notebook from the AC network, but this only decreased this amplitude.
Where could I be wrong? What could produce a 5 Hz signal? Why I can't see the PPG signals? How to properly configure AFE4400's Rx and Tx?
Please, I would appreciate any help very much .
Thank you in advance,
Jurbrian
