In this step-by-step tutorial, you'll learn how to make a very loud, simple, and powerful alarm using everyday materials.

Ultra simple circuit of the tilt sensor alarm presented here can be fabricated using readily available inexpensive components. The circuit is a true transistor based design. Home made Tilt sensor for ...

Cheap, Self-Powered Fire Sensor Could Sound an Early Alarm A new sensor printed on an ordinary piece of paper can send a wireless alert By Karen Kwon ...