Burglar alarm
device · 1853 · Industrial Revolution
Pope’s alarm built on electromagnets.
What it is made of
- Motion sensor — has part. Motion sensors.
- Electromagnet — has part. A bell.
Principles and materials it uses
- Copper — is made of. The contacts are copper.
- Wi-Fi — uses. Modern alarms send alerts to your phone over Wi-Fi.
- Smoke detector — uses. A security system often includes smoke detectors too.