There are a few different water flow meters out there, but this one has one obvious feature that sets it apart – it’s brass! Many of the flow meters you can find online are plastic, or have substantial plastic parts, but this one from Adafruit is mostly brass. This allows it to
function in a much harsher environment, and it should last a lot longer than its plastic equivalents.
The flow sensor consists of a little pinwheel that spins inside the pipe fitting. You can count the rotations, via a small magnet and a Hall effect sensor, and get a good estimation of the amount of water that has passed through. The key here is estimation. Each pulse of the pinwheel represents 2 millilitres of fluid. That estimation is dependent on the flow-rate, orientation, and pressure. You can calibrate the sensor for your application and, for most gardening purposes, it is accurate enough with minimal calibration.
They give the sensor a 9/10, saying “Robust enough for outdoors.”
Stop breadboarding and soldering – start making immediately! Adafruit’s Circuit Playground is jam-packed with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with the drag-and-drop MakeCode programming site, learn computer science using the CS Discoveries class on code.org, jump into CircuitPython to learn Python and hardware together, TinyGO, or even use the Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for CircuitPython, MakeCode, and Arduino. It has a powerful processor, 10 NeoPixels, mini speaker, InfraRed receive and transmit, two buttons, a switch, 14 alligator clip pads, and lots of sensors: capacitive touch, IR proximity, temperature, light, motion and sound. A whole wide world of electronics and coding is waiting for you, and it fits in the palm of your hand.