4 ms·
MEMS barometers are commonly used for relative altimetry (e.g. stair climb calculations on activity trackers, etc).
by pndmnm 14y ago
MEMS barometers are commonly used for relative altimetry (e.g. stair climb calculations on activity trackers, etc).
- jlgreco 14y agoHow accurate are they for relative altimetry indoors? I could imagine climate control throwing in a decent margin of error if all the inputs/outputs (vents and blowers?) aren't balanced correctly. Edit: They probably carry barometers already, but AC installer people could make use of phones with this hardware.
- mikeash 14y agoI don't think HVAC systems will do much damage there. I have a gadget on my airplane that gives altitude accurate to the foot, and that's while moving 60MPH or more through potentially turbulent air.
- jlgreco 14y agoI am thinking more about actual differences in atmospheric pressure between indoors and outdoors, or even between rooms in a building. If the ventilation system is installed correctly this shouldn't happen, but if it is not then you can cause either an overpressure or underpressure in the building.
- mikeash 14y agoI don't think buildings will sustain much of a pressure difference. For example, a 10ft-equivalent pressure difference will exert a roughly 16 pound force on a standard residential door, which would be highly noticeable, and it's probably tough to seal a building well enough to contain that kind of pressure.
- jlgreco 14y agoHmm, I had no idea that pressure differences between altitudes were that great. Fair enough.
- deleted 14y ago[deleted]