High Powered Rocketery Sensors

[Liperthgar]

Hey Avionics People !

What would you use as an IMU if your rocket undergoes 20g for a small amount of time?
We are building a rocket to reach 8km's ( about 25 to 30k feets).
BNO055 is a nice one but it's operation range is less then 16g for its accelerometer. I don't know if it brokes after exceeding 16g. What are your thoughts about the subject ?
Do you have any idea of which IMU to use ?

 

[jderimig]

If you mount the 16g IMU 45 degrees off the rocket axis then you can measure up to 22.5g.

 

[Liperthgar]

If you mount the 16g IMU 45 degrees off the rocket axis then you can measure up to 22.5g.

Wow! That's fantastic to know. It makes a lot of sense. Thanks a lot.
I found a 6DOF Breakout Board: LSM6DSO32 from Adafruit. Thinking about using this module. By any chance can you take a look at it ?

 

[jderimig]

Wow! That's fantastic to know. It makes a lot of sense. Thanks a lot.
I found a 6DOF Breakout Board: LSM6DSO32 from Adafruit. Thinking about using this module. By any chance can you take a look at it ?

However I would prefer you find an accelerometer with more accelerometer range. The above chip you referred to would be a better choice.

 

[LithosphereRocketry]

Wow! That's fantastic to know. It makes a lot of sense. Thanks a lot.
I found a 6DOF Breakout Board: LSM6DSO32 from Adafruit. Thinking about using this module. By any chance can you take a look at it ?

The LSM6DSO32 is perfect for that- however be aware that it doesn't include its own sensor fusion chip as a lot of other sensors do, so if you plan to calculate orientation etc.
in real time you'll have to do that math yourself.

 

[waltr]

Yes, the LSM6DSO32 is perfect for your requirements with a max of 32g's and includes a Gyro.

Another method used by some of the Altimeter/flight computers is have two Accelerometer. A 16g one for resolution of lower g part of the flight and a high g one (100g) for the thrust part of the flight.
If the acceleration exceeds the maximum the output value is just the max value. All of these acceleromters can withstand much more without damage. Read the data sheet for the accel chip to find this value. Example of the LSM6DSO32, the Absolute maximum ratings is 20,000g for 0.2ms.

Also beware of the IMU fusion stuff as most of these are for robotics and use the Accel to obtain an Earth reference direction. This does not work on a rocket in flight.