Posts made by earla

This sensor is surprisingly difficult to use but I still learned a lot. As suggested, I took a look at the raw data from the sensor using an M5Stack Arduino program. Although you can see the pulse data, it is very unstable, noisy and has a varying offset. Here is a very good description of what it takes to make the MAX30100 work.
https://morf.lv/implementing-pulse-oximeter-using-max30100 In addition to what the article says, the two Heart sensors I have behave differently and would require individual calibrations.

@basgoossen Thank you for this excellent information.

@ajb2k3 Yes - I am making progress - working on the calibration against a medical grade device. Thank you!

@teastain Yes! Binding it to my finger makes it work properly! Thank you!

Seeing the module code M5Stack is using would certainly help, but I don't know how to do this of if it is even possible.

I just received 2 new Heart Units and have tested them using UiFlow & the supplied test code or slightly modified versions of the test code. Both of the units read the heart rate at about 2x the actual rate or sometimes randomly. The SpO2 readings are close when compared to a medical grade Pulse Oximeter. Experimenting with the LED current settings sometimes makes the units work properly, but it is very intermittent & will not repeat with a core restart. Experimenting with the timing delays produces similar results.

I connected a logic analyzer - data pulses seem to agree with the delays specified in the code.

Has anyone figured out how to improve the results with these Heart Unit devices? Is it possible the Core 2 can't supply enough current to the Heart Unit?

Hi - I can only light up the first 13 leds on my hex rgb led unit using UiFlow. I set the led number to 37 and tested on both the M5 Core 2 AWS and the M5 Stickc Plus with the exact same results. Am I missing something?

Update: looked at this HEX RGB
unit under a microscope. It looks like this particular unit had soldering problems. There was excess flux, 2 solder blobs and the tops of some leds are melted with bubbled plastic - soldering looks fair. Cleaned board but no change - still only 13 leds

Update 2 - purchased some new ones - all work perfectly and look fine