I want to homebrew a sensor for measuring stream (creek) height as the distance through the air from the bottom of a trail bridge to the water surface. Battery operated, so want low power and only need low sampling frequency (~10 min). What would be the best sensor technology (uwave, lidar etc), and Sparkfun sensor for this purpose? Application is for a volunteer citizen-science stream hydrology monitoring project to replace the normal practice of using human eyeballs to read a staff gauge. About 4m max distance to water surface under bridge. Can waterproof the enclosure, except presumably need small opening for sensor hole of course. Hopefully no goats or trolls under bridge.
I’d recommend this sensor https://www.sparkfun.com/products/18009 - our hookup guide https://learn.sparkfun.com/tutorials/ga … troduction can show you how it’s used/what else you’d need
The main issue will be that water isn’t very reflective…I’ve done some testing and have found that if you create code that simply reports the lowest reading observed, it is fairly accurate (but keep in mind the readings are fluctuating wildly…we’re looking for the ‘closest’ value among those)
You could also rig up a small floating platform that stays stationary for the sensor to reflect against…piece of wood with string/stake, pole with floating donut around it, etc
I would also recommend ultrasonic rangers:
Another sensor to consider:
https://www.sparkfun.com/products/11309
These are very reliable and easy to use.
^Those are much better ideas than what I suggested 