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ihewitt / VO2max

Source code for VO2 max device
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change SCD30 for diffrent sensor #2

Closed smalecki closed 6 months ago

smalecki commented 1 year ago

Co2 sensor SCD30 have not enough range. 40000 ppm is 4%. During exhale without exercise we have about 3-4%. During exercise is more than 4%. Don't found replacement for that for now.

ihewitt commented 1 year ago

yeah although the CO2 sensor isn't crucial to getting the VO2 max calculation and is just providing some additional resp data. Also I think it improves the calculation since it can be used to provide the values for the respired air temperature and humidity. (although obviously these aren't wildly variable and probably doesn't improve much over having hardcoded defaults) and as you say I also didn't see any suitable replacement either.

kongmu511 commented 1 year ago

some dev-board to reference, https://www.co2meter.com/collections/scientific-medical

ihewitt commented 7 months ago

Thanks, yeah I can't see anything small enough or cheap enough to make sense anywhere. (finally got around to taking a look at this again! 🙂) I try out the ENS160 sensor to see if that can be used. (goes to 6.5%)

ihewitt commented 7 months ago

FYI switched to a ENS160 (with AN41) to test and it no longer maxes out, but doesn't seem to give values high enough for the exhaled air. (although this is an eCo2 sensor rather than a direct sensor) I'll test a little more, but I don't think using eCO2 sensors (either) is of much use really.

ihewitt commented 6 months ago

Ongoing - more co2 sensors on way, will update site with details after building/testing.

ihewitt commented 6 months ago

FYI I added some notes about using a different sensor here (and uploaded the code - https://github.com/ihewitt/VO2max/commit/3321b3691952aad3dd693bd3de983f4fc1948c81) Notes - https://blog.ivor.org/2024/03/the-ongoing-vo2-max-saga.html I'll add the details to this repo also.