Expanding the capabilities of your Arduino is easily done by adding a shield. Plugging directly into an Arduino and typically including custom libraries for easy coding, sheilds provide a quick way to expand a project. In his Weekend Project: Cellular Sensor Sentinel, Adam Wolf uses a Seeed Studio GPRS/GSM Shield to send text messages when sensors are tripped.
Here we’ll teach you how to connect simple motion, touch, pressure, and light sensors, and how to program the Arduino to use the shield to send text messages when these detect events. It’s easy to adapt this system to use other sensor devices like temperature probes, magnetic switches, tilt sensors, etc.
Check out Adam’s use of a shield in Cellular Sensor Sentinel and consider adding one to your next Arduino project.