🔦 What Was the Detect-O-Ray?
Long before Ring doorbells and Nest cameras, there was the Detect-O-Ray—a pioneering photoelectric security device introduced in the early 1940s.
Think of it as the grandfather of today’s motion sensors, but built on pure analog ingenuity.
How It Worked:
One unit emitted an invisible infrared (or visible red) beam across a room, doorway, or hallway.
The second unit—directly opposite—acted as a receiver.
If someone (or something) walked through the beam…
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