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What is the best airspeed sensor?

Hi I have always had trouble with the standard 4525 airspeed sensor. Have to calibrate multiple times during a flight day, sometimes says the static and dynamic need to be swapped after functional use, and then they just start reading bogus values and I have to switch out the entire sensor. Then it works fine the next day. Anyway, I want to get a new airspeed sensor and I don’t know which one is the best.

4525 (which seems to be made by multiple manufactures: https://store.mrobotics.io/mRo-I2C-Airspeed-Sensor-JST-GH-p/mro-classy-arspd-mr.htm

5525: https://store.mrobotics.io/mRo-Next-Gen-MS5525-Airspeed-Sensor-NEW-p/mro-ms5525v2-mr.htm

EagleTree: https://www.eagletreesystems.com/index.php?route=product/product&product_id=63

Sensirion: https://store.drotek.com/sdp3x-airspeed-sensor-kit-sdp33

To me it seems the sensirion would be the best because it comes pre-calibrated and temperature compensated. Any insight would be appreciated.

I am using this on a fixed wing platform flying between 10-20 m/s. At the beginning I will be flight 100m AGL (1540m MSL) but have plans for very high altitude flight in the future.

Avoid the Sensirion one, ArduPilot dropped some atmospheric correction terms which don’t really matter at sea level, and really do matter at higher altitudes.

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The DLVR is easily the best of the supported airspeed sensors.
UAVCAN is also an option.

I’m pretty sure we dropped support for the Eagle Tree sensor quite some time ago, so you can cross that off your list.

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Is there a DLVR kit that comes with the sensor, board, and pitot tube?

Not that I’m aware of. Mine has the same pinout as the ms4525 though, so you could probably just remove the 4525 from the pcb and drop in the dlvr.

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What kind of airspeed ratio do you guys have set for the dlvr? When I do the preflight calibration on it I’m getting an “airspeed 2 unhealthy” message, whereas the 4525 is fine. I’m getting readings but showing super high airspeed on a 20m/s blow (finely calibrated of course…lol)

I use the same ratio as the old 4525. What model is your DLVR?

L05D, or is it some other setting like the psi range which I can’t for the life of me tease from the datasheet

My attempt at this just now didn’t seem to work. Direct I2C worked (with the unhealthy message), but putting in place of an MS4525d on a px4airspeed v1.1 or v1.2 board didn’t work at all.

Theres a really long number, which also involves if it’s a free running/noise reduced etc, that’s sorta the number I’m curious about. Also just to be sure what plane release are you using, and did you change the ARSPD_TYPE to the DLVR one? (And get the bus right?). The MS4525 can kinda understand a DLVR and vice versa but it goes a bit wrong even though they are talking and sorta get it right. This mostly causes problems when a MS4525 is enabled and scans onto the DLVR bus before the 4525 is found. (Dual airspeed sensors is a large trap of ways it goes wrong atm)

I’m messing with this on the bench, so I’ve got 4.0.0beta2 on a CubeBlack. DLVR-L05D-E1BD-C-NI3F, next number on the chip is R18J05-33

Airspeed Type set to 7 (which I think is right for this chip) and alternatively 9, tried different busses, and with and without the MS4525 on. The MS4525 was AIRSPD_BUS=1, and this chip is on the same physical bus, but I noticed with the SDP3x I had to set a diffrent bus than the MS4525, I2C fundamentals is not my stong point, but I’d love to learn.

So that’s part of the problem I was referring to with the 4525, the BUS parameter doesn’t have any effect on it. The net result being that it always scans in a fixed order and may be talking to your DLVR by accident. Start with just the DLVR connected, with that being the only airspeed sensor you’re looking at.

That’s the fast variant which should be fine. I use the noise reduced one but as long as it’s not the sleep one it should work.

Awesome thanks, I’ll give it a shot. I would love for someone to add this to their shop like @paan2097 was querying about. a board would be nice. I do have a .1uf cap on the chip as you suggested.

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