Servers by jDrones

Airspeed Sensor Calibrating

(Lbarreiro) #1


I have install the airspeed sensor and made a flight to calibrate it as showed in the wiki (loiter for 5m with ARSPD_AUTOCAL = 1)

This is the graphic from that flight - First the loiter for calibration and without landing (wireless telemetry) i have disable the ARSPD_AUTOCAL, can someone tell me if it´s ok, and that i may use it?


(James Stewart) #2

I like to go for longer than 5 minutes, myself.10 to 15 minutes is usually enough. You’ll know it’s done when that airspeed ratio parameter stops updating.

(Lbarreiro) #3

Thanks James

I also stop because the airspeed ratio stop updating after 5 minutes, and the final value is 2,7 (in the limits)

The only concern is because the readings are a little noisy. I don´t know if it´s safe to use the airspeed sensor with this readings.

Thanks again

(James Stewart) #4

What sensor are you using? Noise is a common issue with airspeed sensors, especially cheaper ones.

(Lbarreiro) #5

this one

(James Stewart) #6

Okay, that’s pretty much what I was expecting. I’ve worked with some of the 4525DO based sensors before, noise is common on them. I’ve seen fluctuations on the ground of up to 7mph, and noise in the air as well. As long as you gut-check it during flight by watching your as/gs and wind speed estimates through telemetry, you’ll be ok.

If you really want to cut down on the noise, I recommend the SDP3X sensor from Drotek. It’s an entirely different type of sensor, and it seems to perform much cleaner, especially at low speeds. However, it’s an $80usd package once you factor in shipping costs, so I can see why many people don’t use it.

(Lbarreiro) #7

Just order one to test :slight_smile:

mean time i´l try to isolate the cabling to see if the noise is RF related.

Thank´s for your help.

(Anthony) #8

I’m using shielded cables only. For all signals, no matter what. Basically I2C is for communication of devices and components that are normally on 1 single PCB. It was never intended to be further away than a few centimetres. So using shielded cables is almost mandatory.