There are plenty of times when you could probably use a heads up as to what is going on inside your home, like when the basement floods (again), or when the back door gets left ajar, and there are a slew of home automation solutions that can help with that - but none of them as simple as Twine.
Twine, begun as a wildly successful Kickstarter campaign, is a 2.5" blue cube that more or less resembles a package of standard-size Post-It notes and holds on-board sensors that can measure changes in temperature, movement, moisture and more. It then uses internal WiFi to alert you to the changes via text message, email, or tweet which means Twine can send you a text message letting you know that the pizza guy is at the door, email you when the laundry is done, or send you a tweet alerting you that the fridge door is open.
Because Twine reacts to general physical changes (temperature, moisture, movement), it can be used on a variety of objects. Twine has both internal and external sensors, with the initial set of sensors measuring temperature, accelerometer (for vibration, impact and motion detection), moisture, a magnetic switch (for doors and movement) and a breakout board with an analog and digital input, power and ground so other sensors can easily be wired up. DIYers will appreciate the ability to connect your own sensors and use HTTP to have Twine send data to your own app.
Twine is designed hand-in-hand with it's accompanying cloud-based web app, Spool, so setting it up is as easy as pointing Twine to your WiFi network and selecting a few rules on the website. You can set rules on Spool to trigger Twine from anywhere; the rules themselves are set up in plain statements such as "WHEN Twines accelerometer is KNOCKED, then TEXT that someone is at the door." The sensors are instantly recognized by the web app, so you can see them connect and respond in real-time, and rules can be created and shared among Twine users.
Twine runs on either a USB connection or two AAA batteries, which should last for months and will alert you when the batteries are running low. While Twine can be pre-ordered, it won't ship until September which gives you plenty of time to plan out what you'd like to connect it to.
Images courtesy Twine on Kickstarter, Supermechanical