I ordered the arduino capable flow meter, and it doesn't work. I spent a few days troubleshooting it, no luck!
I've successfully had the seeed version a while ago, so I'm sure it's not a bad schematic.
The code is the sample code from https://github.com/adafruit/Adafruit-Flow-Meter
The schematic: arduino Digital 2 to the yellow pin (sensor), 5v (via the arduino 5v pin) to the red input (5v), and grounded to the arduino ground. It picks up 0 for all it's readings.