Wave height calculation
Has anyone ever played around with calculating wave height from an onboard acceleramoter?
13 Replies
With high quality barometric pressure sensor, you could measure +-50Pa absolute accuracy levels, relative accuracy is even better, ~1/10 of abs level.
That's incredible. I never knew you could measure altitude that precisely with a barometer. Have you tried it to measure wave heights?
My late night calculation were a bit wrong, not sure where I did misstake.
With BMP585
+-30Pa abs = 2,5m
+-6Pa rel = 1.0m
Not accurate enough..
After your message i did find the device below which claims to be ±3Pa = ±0.25 meters which is getting there!
https://shop.pimoroni.com/products/adafruit-bmp390-precision-barometric-pressure-and-altimeter-stemma-qt-qwiic?variant=32302189346899
I use node-red to pull in barometer data from my phone. I wonder if that would be precise enough
I have Ruuvitags, but BMP280 is quite poor sensor and not usable for this purpose
- Relative accuracy ±0.12 hPa, equiv. to ±1 m (700 … 900hPa @25°C)
- Absolute accuracy typ. ±1 hPa (950 ...1050 hPa, 0 ...+40 °C)
i tried it with bme280 but nothing of interest came out, too much noise, a gust could probably lower the pressure inside by more than a wave. What might be interesting & useful is data from the Pypilot compass, https://shop.pimoroni.com/products/icm20948?variant=27843993960531
Roll & pitch are send by default, accurate enough to see me move from a seat to the chart table, might be a way of getting at the accelerometer data as well.
Oh intresting, I never thought about wind gusts changing pressure in the cabin 😆
Lots of variables... Though the BMP280 I have is very sensitive, it picked up load & clear the pressure wave from the Fuji volcano eruption year or so back, for a few days I was wondering WTF WAS THAT?? 'til a link came up talking about it somewhere.
You wouldn’t be able to use pressure to measure wave height. Pressure more or less aligns to the wave profile. In trochoidal model which is pretty close for deep sea waves the air pressure is equal on the wave surface
For e.g. Baltic sea and especially coastal areas, archipelago, pressure based sensoring should work fine. Deep sea, ocean, it is different.
Measuring wave height with barometer wouldn’t work in Baltic Sea, coastal areas or archipelagos. Of course you can try proving otherwise by implementing it and getting results with reasonable accuracy