There you go: probably don't need a smart sensor, but if you do, probably shouldn't use an Arduino. Ah, if only I had specified the use of an nRF52840 from Nordic Semiconductors, a 32-bit ARM® Cortex™-M4 CPU running at 64 MHz. with 1MB of program memory.. .Not sure if you really need "AI" and a neural network to do frequency analysis of your engine sound.
But an arduino is probably not the good plateform for that anyhow. Good idea though!
No, I haven't, but that sort of makes sense, except the Rotary 13B is supposed to be smooth.Hey Finn,
Have you seen the comments from RV12 drivers that they've had problems balancing Rotax 912 props due to multiple vibration freqs from the engine itself, the gear box, and the prop? Since drives typically use 'hunting tooth' ratios, the freqs don't look related to each other.
Reflective alum tape on one bolt shank end, the other bolt ends and nuts black with a sharpie. I am getting an excellent signal from the one bolt.What are you using as a reflector on the prop blade?
OK, so not as simple as I thought it would be.1. Collect data with a dummy channel indexed to an odd multiple greater than one of the rotating mass.
2. FFT the results.
3. Extract the magnitude and phase data, and relate it to the position to mass compensate.
This requires very little effort, and coarse data at some sampling rate greater than twice the rotational speed will eventually capture the vibrations similar in frequency to the engine speed. Go for 10x the engine speed to capture higher frequency components.
It is largely how tire spin balancers work, with almost no other tricks, without strain gauges.
So the scope shows a straight line?OK, so I got the ADXL335 and hooked up with a photo sensor, mounted it to the neck of RWS redrive in my RV-3B and hooked it up to a 4-channel scope. Channel 1 for triggering and channel 2 for the z-axis from the ADXL335. The scope has a number of math functions, like Integral, Differential, Average, etc.
Running the prop up to about 1,400 RPM I simply could not see any pattern, even when removing the 25g weight the builder had added when balancing the prop with a Dynavibe.