After you’ve broken two laser tubes (one chinese, one high quality) because of lack of refrigeration, it’s about time you hodor honor the promise of making that damn waterflow sensor you said you were going to make in the first place the first time you broke the laser.
Everything starts with a drawing:
Nice try, but no, that’s not even a (blood) flow detector.
Looks like a plan, doesn’t it? XD
Let’s build something…
Cut and drill the acrylic as needed:
Mill some slots for the water to run past the buoy:
Add magnets, of course!
Acrylic rod drilled and sealed with epoxy.
Polish:
Glue nicely to prevent leaks:
Mill a slot, glue some reed sensors (since it’s not a tachometer, you don’t really need hall effect sensors), add connector of your chosing. I used a DB9 because I want all the connectors for external devices to be all different, so I can’t mistakenly connect two.
Succes!
How it works:
The magnet buoy resides at the short piece, acting as a loose plug. Once water starts flowing, it will push it upwards, however, if there is not enough flow, the venturi effect will prevent the buoy to get past the slot interface and up to the top of the sensor, signaling for a decreased flow, probably because of clogged filter. If there is nothing wrong with the setup, the water will swiftly push the magnet carrier up to the top of the assembly, activating the laser enable and allowing you to lase whatever you want.
So, the laser is safe-ish, for now. ^^
The Electronic Mercenary 
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