Automation should be easy and if what you need is simple on/off input and confirmation there’s no need for fully customized gear. For those applications, the QK-G–21 GSM/SMS Remote Controller lets you control and monitor equipment remotely via text message.
In action, a text message can be sent to up to four phones when one of two possible alarms are triggered, and users can operate three relay outputs via an SMS text app. The device features a GSM sim card, making it usable in Europe and the US.
While the possible applications for a device like this are limitless, one scenario envisioned is for use with a liquid tank, where an operator can remotely trigger a valve to fill it up. Feedback could be provided by a high and low level sensor, confirming that the device has indeed done its job. While meant as a standalone device, there’s no reason why these I/O pins couldn’t interface with an Arduino or similar, allowing it to trigger a complex sequence with this simple control method.