This project has for purpose to completely automate the usage of rain water collected from roof in an external tank and switch to water from city supply network when external tank is empty.

As physical constraint, the water pipe coming from city supply network must never be in contact with rain water to avoid city water contamination. So a small internal tank is used to mix water sources.

This water can be used, for example, for garden watering when required.

This project is also used to monitor:

• the rain water level in external tank and if empty or not.
• rain water usage
• city water usage

This project is using:

• Arduino Nano
• ENC28J60 chip as Ethernet interface (see Ethercard, some fix are not yet included in upstream)
• SEN0208 weather proof, ultrasonic sensor
• 4 Channel DC 5V Relay Module with Optocoupler for Arduino
• COAP protocol (no other purpose than testing COAP, sources are from microcoap)
• Jeedom as monitoring interface

Water equipments:

• Solenoid valve to control water from city supply network (Danfoss EV251B 032U538131)
• Transfer pump to move rain water from external tank to internal one.
• Water pressure booster to provide pressure in a dedicated network.