Hi all, I’m researching enclosure and PCB thermal design for an indoor air quality monitor and have been reading the ONE v9 KiCad files and this forum. Three things I couldn’t pin down from the docs:
-
SHT4x vs SGP41 sub-board placement. What is the physical spacing between the SHT4x and SGP41 sub-board sockets on the ONE v9 main board, and was that distance chosen from a measurement? Sensirion’s design-in guide asks for ≥2 cm plus milled slots, so I’m curious how much the SGP41 heater actually raises the SHT40 reading in the final enclosure.
-
Built-in temperature compensation. The calibration docs say the ONE’s raw SHT4x data is already close to reference, yet a lot of threads here report +2 °C or more. Does the current firmware apply any offset or model to SHT4x on the ONE, or is it raw? Any idea how much of the spread is orientation (vertical vs flat) vs unit-to-unit?
-
S8 lock-up (GitHub #320). The issue shows the S8 stops answering (“Unexpected length”) until a full power cycle; an ESP warm reset doesn’t recover it, so it looks like the S8 itself hangs rather than the ESP UART. Has anyone scoped the 5 V rail or UART lines when it enters that state, or heard back from Senseair about S8 FW 1.2? For a new design I’m planning a MCU-controlled load switch on the S8’s 5 V so firmware can power-cycle it — does that match what AirGradient has seen?
Thanks — happy to share my findings back here.