Everything-that-moves ALARM Project

A crucial failing of proximity detectors is their unreliable and tricky nature. This is where they are used to detect humans, not to speak of smaller living beings. One common approach is to detect...

Air Flow Detector Project

This simple circuit uses an incandescent lamp to detect airflow. With the filament exposed to air, a constant current source is used to slightly heat the filament. As it is heated, the resistance...

Sound Operated Switch Project

Circuit diagram  Notes: This sensitive sound operated switch can be used with a dynamic microphone insert as above, or be used with an electret (ECM) microphone. If an ECM is used then R1 (shown...