The GSM Shield also includes a Telefonica SIM card that includes a worldwide data tariff which can be used anywhere there is a cellular signal.

Adafruit has this week made available the Arduino FONA 800 that has been designed to provide Arduino development boards with the ability to enable Arduino cellular GSM via both voice and data.

The Arduino code tells us that the valves will be opened as long as the remote up/down channel is above/under given values.