This is a project for a master degree with the goal of store water flow data in a house.
It uses a flow sensor, connected on an ESP8266 to send it thought the internet to an endpoint. It has a USBSerial to update the ESP8266 firmware and code.
Some research about ESP8266:
Raspberry:
Arduino drive on MAC: Drive Download, install.
Run:
sudo nvram boot-args="kext-dev-mode=1"
reboot