Pixhawk Data Acquisition on Rocket

PX4 Autopilot
1

Hello,

I am a student working on a design project. My job is to build a data acquisition system for a hybrid rocket engine. I want to be able to save data onto the local SD and also transmit data to the ground station. I have a Pixhawk1 from a previous project iteration and I want to use it strictly for the sensors that are built into it. Here’s what I’d like to know:

  1. What components outside of the Pixhawk do I absolutely need to achieve this goal? (I know I’ll need a transmitter, but what kind?)
  2. What flight planning/hardware program do I need for my goal, and how should I go about choosing my firmware?
  3. What are some tips that you can give me, if you are experienced in using this equipment?

Thank you so much,
Will

2

Hey, interesting project! Before diving into the solutions, I would like to clarify your problem:

  1. What kind of data are you trying to log? (Thrust chamber pressure, Temperature, Vibration, etc?)
  2. Will it fly on a rocket? (Since you mentioned ‘flight planning’)
  3. Are there any more resources / websites that I can reference, to get more context of the project?

It would be helpful to have answer to those to understand your objective more clearly :wink:

4

Hello. Thanks for the reply!

I am trying to record data for acceleration, positioning (gyroscope), and altitude. All of these sensors are apart of the pixhawk’s internal hardware. It will fly on a rocket, but I don’t necessarily need it to control any components (i.e. parachute, motor, etc). I simply need to take flight data, store it to an SD card in the Pixhawk, and (optionally) transmit data to a ground station. When it comes to extra resources, I’m not sure exactly what you would need.

Best case scenario: Pixhawk records data, transmits and stores data.

I’m using this sophisticated piece of equipment for something very simple, I know, but it’s what I have and any cheap sensors that I’ve tried using have been painfully unreliable.

Thank you very much.

5

Ah ok since you said ‘engine’, I thought you meant logging the engine characteristics, and not the data. So you are going to collect data from a ‘rocket’.

Hardware

I think what you need is:

  1. Pixhawk (or any supported hardware)
  2. Telemetry radio
  3. SD Card
  4. GPS

Software

Then, you just need to configure the logger to perhaps log from boot until shutdown, since you won’t be ‘arming’ the vehicle.

Then, as long as you have the orientation correctly set (check via QGC if the orientation of the rocket makes sense), the logger should provide you a good overview of position/acceleration etc.

Let me know how it goes!

Note: This is *sort of related discussion in discord about rocket airframe file, but not really helpful (just posting to keep track).