Airspeed sensor calibration problem

Hi, I am using a Matek airspeed sensor ASPD-7002.
When I recalibrate it in a few minutes after turning power on, I get pretty good readings in still air, close to zero (0-3km/h, sometimes 4-5).
But I usually don’t have a computer in the field.
Soon after normal switching on and calibration, the speed readings are about 13-15 km/h in still air.
Turning the power off and on doesn’t help. I tried to warm up the electronics for ten minutes, disconnect the battery and connect it back, airspeed drifts soon to the same 13-15.

Is it possible to extend the power-on delay before calibrating the airspeed sensor?
Or assign Preflight_Calibration to some RC channel?
Or maybe this is not a problem, so I shouldn’t do anything (but I get stall recently due to incorrect airspeed readings, luckily without crash)?
Or I should change sensor to Matek ASPD-DLVR?
Or is it better to add bluetooth and use some mobile application like QGroundControl to trigger Preflight_Calibration?

Unfortunately it’s a known issue. Airspeed sensors drift with temperature and humidity.
I would suggest that you power on your UAV and let it sit for about 10mins. Then cycle the power to reboot it and re-calibrate the airspeed sensor. This should get you a better offset.

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yep that works been doing it for years :+1:

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Thank you for the explanation. Finally, I added bluetooth and installed QGroundControl on the mobile phone, so I can trigger Preflight_Calibration without disconnecting the battery.