I would like to build a tide station that can measure rate of flow. any ideas on what module would help me do this. can i use a servo to measure if it is being rotated by an outside force?
Thanks
Antigroove
You will have to provide a lot more info I think. Personally I cannot figure how a servo relates to tidal flow.
At a guess I'd suggest a paddle wheel and count the pulses from it or a stress gauge with a paddle in the water and measure the voltage off the gauge.
Rob
Flow? Do you mean you want to measure the tidal current in a particular spot? Or do you want to measure tide height? If height, maybe an ultrasonic sensor.
Maybe a paddle with an optically encoded axle and ir setup? Hardest part will be with little movement back and forth, you may need a decent resolution if you want that,
I would have thought to get the best measurement you want an unloaded turbine or some sort with a hall-effect sensor to measure the rotation speed. Using a servo motor would load the turbine and reduce its hydrodynamic performance - there are specialised water flow-rate measuring devices available commercially, they might provide inspiration.
How about a vaned/finned-body with a balloon inside (pressure sensor) tethered to the bottom, as the current flow increases, the flow on the vanes makes it dive down, increasing pressure & squeezing the balloon? Or whatever depth guage divers use, maybe there's one with a digital output that could be captured.
Interesting idea.
If you made a type of buoy and weighted it to the bottom (if shallow enough), you could have a single arm stuck down into the water and the current could push the arm which is connected to a variable potentiometer which you can read with an analog pin. Not saying it's the best way, but it's just an idea.
I don't know, sounds like a waterproofing nightmare!