karla

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MS4525DO (pixhawk) Digital airspeed sensor connection I2C
« on: December 01, 2019, 08:41:01 am »
Hello  :)

Following advise and hope to have PH, RTL, PP flight modes working better for my fixed wings I want to install an airspeed sensor to my Revo board with LP 16.09 r782. Reading up on articles it seems most suggested that digital airspeed sensors have superior range and precision to analog ones that has a lot of noise issues. Since I saw there seem to be support for a well known digital airspeed sensor from pixhawk, I got some units and installed them but the System Heath show I2C as black and AIRSPD as black red crossed over.





I have been reading up on another user, way back that tried to get that sensor to work with a Sparky board.
https://forum.librepilot.org/index.php?topic=3483.0
I am not sure but seems he got it to work after resolving some issues with 5V respectively 3.3V from the sensor?

Anyone already got this sensor working with a LP on a Revo board?

I have followed the wiki
. configured the FlexiPort as I2C
. HWsettings OptionalModules Airspeed Enabled
. Set AirSpeedSensorType to PixHawkAirspeedMS4525D0
. Connected the unit to Flexi port according wiki for pins SCL, SDA, GRD, 5V and the unit.
(I have no other i2c sensors on the system, use internal mag and a GPS on the main port)

Any ideas how to move forward?
Should I just move on and get an analog sensor that user JDL since he apparently got it to work nicely?


Re: MS4525DO (pixhawk) Digital airspeed sensor connection I2C
« Reply #1 on: December 01, 2019, 09:43:56 pm »
Hello,
  FWIW, I'm using the EagleTree V3 sensor for dynamic PID tuning.  It's working great for that, but I can't get it do display any value on the GCS when testing.  Maybe it's an arming dependency or something?  Either way, I can confirm that it actually does change the PIDs, so it might be worth trying.

Re: MS4525DO (pixhawk) Digital airspeed sensor connection I2C
« Reply #2 on: December 01, 2019, 10:36:03 pm »
@ufoDziner:
Hmmm... you should at least be able to set up and watch airspeed on the Scope page.  You will have to set up AirSpeedSensor in the Tools drop down -> Options -> Scope and then set it up on the Scope page.

@karla:
JDL and I discussed the MPXV7002 airspeed sensor and both of us got it working.  In that thread, I just changed the link to buy it to a valid link.  It sounds like you should be able to get the one you have working though.
https://forum.librepilot.org/index.php?topic=3518.0

This is the sensor.
https://www.xt-xinte.com/Ardupilot-Arduplane-Airspeed-Meter-Sensor-Kit-With-Pilot-Tube-for-APM2-5-2-6-2-8-Flight-Controller-p138778.html

karla

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Re: MS4525DO (pixhawk) Digital airspeed sensor connection I2C
« Reply #3 on: December 02, 2019, 02:48:55 am »
Thank you @cliff, that is a fine plan b.
I will try a bit more to use this higher quality sensor.
I think user @wondersea and @f5soh already solved this in another thread:
https://forum.librepilot.org/index.php?topic=2907.msg20342#msg20342

It seems indeed be about 3.3 vs. 5 volt signal mismatch between sensor and the I2C port.
I will see if I can get mine to work and write up how to do it and where to buy things if succeed.
« Last Edit: December 02, 2019, 10:40:47 am by karla »

Re: MS4525DO (pixhawk) Digital airspeed sensor connection I2C
« Reply #4 on: December 02, 2019, 05:43:49 am »
Thanks @TheOtherCliff.  I will test.  The only place I was looking was at the airspeed indicator on the "Flight data" tab.  It makes sense to me that it would be displayed there.  While that never displayed the info, the "AIRSPD" indicator was green, and I could see the controls scale down when blowing into the tube.

f5soh

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Re: MS4525DO (pixhawk) Digital airspeed sensor connection I2C
« Reply #5 on: December 02, 2019, 06:11:19 pm »
Quote
Anyone already got this sensor working with a LP on a Revo board?

Yes, works perfectly and pretty accurate without calibration.




karla

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Re: MS4525DO (pixhawk) Digital airspeed sensor connection I2C
« Reply #6 on: December 03, 2019, 03:34:11 am »
Thanks! Very useful.