At Carriots we have created this nice and very simple tutorial: How to connect a Raspberry Pi to Carriots and build an Alert System. http://www.carriots.com/tutorials/raspberrypi_carriots/alert_system
This systems detects lights and send the information to Carriots where an Application is built to send you a warning via SMS. This tuturial could be the first step to do a DIY home alert systems based on motion detectors or door openings sensors.
Carriots is FREE to use for up to 10 devices. The free account also let you sens SMS and emails!
For less than 75$ in HW you can have your own Home Security System with no montly costs!
Here is the project Schema of the project:
|Raspberry Pi model B||Raspberry Pi|
|Basic USB optical mouse||IONE / Pro Signal|
|120-240v to 5V power supply with micro USB connector||Raspberry Pi|
|Basic USB keyboard||Gear Head / A4 Tech|
|4GB Class 4 SD card preloaded with Debian 6 Linux||Samsung|
|10k ohm, 250mW carbon film resistor||Multicomp|
|Clear acrylic enclosure for Raspberry Pi||Adafruit|
|Female/male 'extension' jumper wires||Adafruit|
|CdS light dependent resistor, 200k dark resistance, 80mW||Excelitas Tech|
|1 uF aluminum electrolytic capacitor, 50V, 20% tolerance||Multicomp|
*Products and resources are listed to help members build their own Pi Projects. For substitutions of any parts, please login to post a question to the original author.