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Help Using Pixhawk Board and Airspeed Sensor

Hi,

I am a senior Electrical Engineering student working on my senior design project. I am looking for a way to measure airspeed, calibrated airspeed, outside air temperature, altitude, and vertical airspeed (with live data and stored data for later). I think I have found a solution but I am not sure, and would like advice and/or help with figuring out which Pixhawk board to buy.

I am thinking about using this airspeed sensor: http://store.jdrones.com/digital_airspeed_sensor_p/senair02kit.htm
with this pixhawk board:
https://www.getfpv.com/pixhawk-4-autopilot.html

Will it measure all 5 parameters? And would I be able to get live data and stored data using the above two by pairing them with a raspberry pi?

Thanks in advance!!

The pixhawk alone should be capable of recording all the parameters you want here, live through mission planner or your GCS software of choice, and later thanks to the logging features in the pixhawk. Outside air temperature might need an external sensor, to my knowledge the pixhawk boards don’t have an OAT sensor. Altitude will likely be more accurate if you include a GPS unit in your build, I’m assuming this is a fixed wing project. Your pitot tube/airspeed sensor will obviously take care of indicated airspeed.

I’m confused by what you mean by calibrated airspeed the definition I know is: Calibrated airspeed (CAS) is indicated airspeed corrected for instrument errors and position error (due to incorrect pressure at the static port caused by airflow disruption).
I don’t think the Pixhawk does anything like that but that is a subject beyond my expertise.

Vertical airspeed is also measured by the pixhawk but I am unsure if it uses accelerometers or the actual static pressure sensor onboard. I know on copter firmware it gives a speed in knots instead of something like feet per minute as you would find in a manned aircraft VSI.

Personally I prefer the Pixhawk 2.1, also known as “the cube”, I’ve had better reliability with them compared to the pixhawk 4. They are a little more expensive so if you’re on a tight budget the pixhawk 4 should still get the job done.

Hope some of this helps!

First of all, thanks for the response!

I have a few questions about what you’ve mentioned here. I want to clear up that we are sensing these parameters separately from regular sensors on the plane.

How does the pixhawk connect to the mission planner or GCS software? Is that something I need to buy? What does GCS stand for?

According to the airspeed sensor page, it says that it measures calibrated airspeed (which is temperature compensated), indicated airspeed, and outside air temperature in combination with a pixhawk board. I messaged a representative on the website and he said that it only measured airspeed so I was confused on the conflicting viewpoints. What is the best way to figure out what parameters they measure?

Thanks for the tip for vertical airspeed, I’ll look into on copter firmware!

Also, I believe that this sensor only works with the Pixhawk 4 specifically.

GCS stands for ground control station. Mission planner is a free software that works great with ardupilot firmware and pixhawk flight controllers. You can connect the flight controller to the GCS via USB or with a telemetry radio that plugs into the pixhawk and a corresponding radio to your GCS.
See here: http://ardupilot.org/copter/docs/common-sik-telemetry-radio.html

Here are some more links that might help you with the GCS stuff.
http://ardupilot.org/copter/docs/common-install-gcs.html
http://ardupilot.org/copter/docs/common-connect-mission-planner-autopilot.html

For your other airspeed questions, if the sensor claims it gives that data then it should be viewable in the GCS software. Although I am a bit confused about your project scope here. Are you planning on putting a pixhawk and its sensors on a manned aircraft and using them along side it? Is this going n an unmanned aircraft? What exactly are you trying to accomplish here?

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