Which sensors are you using on your flight computer?

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Altay

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Hey everyone, I'm currently in middle of a research about sensors which can perform dual deployment for our supersonic, 20,000 feet apogee rocket. But I saw a lot of rocketry teams and rocketry hobbyists using commercial avionics. We don't want ot use commercial systems and we want to build our own flight computers. So if you're building or did build your own flight computer, can you share your experiences with us? Which sensors did you use?

By the way we're currently planning on using these sensors:
  • BNO055: Acceleration for ±16g + Tilt
  • LSM6DS33: Acceleration for ±4g + Tilt
  • BMP280: Altitude
 
Hey everyone, I'm currently in middle of a research about sensors which can perform dual deployment for our supersonic, 20,000 feet apogee rocket. But I saw a lot of rocketry teams and rocketry hobbyists using commercial avionics. We don't want ot use commercial systems and we want to build our own flight computers. So if you're building or did build your own flight computer, can you share your experiences with us? Which sensors did you use?

By the way we're currently planning on using these sensors:
  • BNO055: Acceleration for ±16g + Tilt
  • LSM6DS33: Acceleration for ±4g + Tilt
  • BMP280: Altitude
The BMP280 is fine for altitude, but I personally would switch to the LISD3DH for +/-16G acceleration, or if your thrust/weight ratio higher than 16:1, you might need the ADXL377 which is an analogue 200G accelerometer.
 
The BNO055 is a really nice sensor but since it has a Cortex M0 in it, it can manipulate the data before giving it to you. As long as you know that it's kind of a black-box and work around that, it's a good setup.
 
I've had very good luck with these parts.
Digital high-Gee 3D accel: ADXL375. Or HLIS331 which is trickier to hand-place but I think Sparkfun has a breakout. HLIS100 is only 8 bits. You definitely want higher than 16 G.
Digital baro: MPL3115A2 can read out altitude directly, no fancy math needed. This part may be going obsolete soon.
 
The H3LIS331DL is a good digital accelerometer that is cheaper, and can do 400Gs. I typically set it to 100Gs and 1000Hz, then use a moving average of about 30 points to smooth the data. See the plot below showing the LSM9DS1 vs H3LIS331DL. My personal favorite is the LSM9DS1: It has a good gyro and can handle up to 24Gs, but you have to do the rotation code yourself, which can be challenging if you've never done it before.

The MPL3115A2 is a good sensor, not susceptible to interference (EMI), but a bit noisy. The Bosch BMP280, BMP388, or newer versions are very precise, but EMI sensitive, so don't use them if you have telemetry. If you want higher rate data at about 100Hz with Bosch-like precision and not EMI sensitive, then the MS5611 is a good choice. See the plot below of the MPL3115A2 near apogee from one of my flights yesterday.


LSM9DS1 vs H3LIS331DL.pngMPL3115A2 near apogee.png
 
Invensis 20600 IMU
HP203B pressure sensor. (Small part count to make work)
SPL 06 pressure sensor (cheap and small)
LPS25HB pressure sensor. (good)
On the lookout for a good higher g accelerometer. Going to be testing the QMA7981 which will do 32g. Since I fly mainly sugar, most flights are 10-20g, which means I saturate the 16 g accelerometer. 32g might be a sweet spot.

I like the H3LIS331DL but it is an expensive part!
 
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