For some time this was a very complicated and expensive task, but wait no more! There is a very easy solution for all your woes.
Things you need to make your home gates open with SMS or make coffee machine welcome you with a fresh pot of coffee after a long day at work:
- Gammu SMSD
- An old phone with USB cable
- Some wires and maybe a couple of electronic components
- 20 lines of Python script
The solution is to hook up your old phone to RaspberryPi and set up Gammu to listen for incoming text messages. Gammu supports a very wide variety of phones so it is very likely that your old forgotten Nokia is well supported.
The most crucial part of this setup is now ever popular 25$ RaspberryPi. It has lots of extension ports, that you can use to hook up almost everything. Also it has loads of libraries and extensive community support.
You could very easily make a 20-line Pythin script, that listens for incoming SMS and opens your gates on SMS-commad.
Happy coding and get the most out of your RaspberryPi!