Category Archives: detection


Sensors used in smoke detector

The most common smoke detectors are powered by two different scientific forms of readings. The first one is chemical-based (relying on ions in the air), and the other being light-based, relying on the changes and charging of photocells (light-rays) and their density or exposure.


The light-based smoke detector simply relies on changes of light within it chamber that relies on such changes as an indicator of smoke or disruption, in turn triggering the alarm.

Ionization Smoke Detectors

The most popular and commonly used smoke detectors are based on ionization changes within their built-in chambers.

Inside of an ionization based smoke detector there is a science taking place. Essentially, using radiation, Americium-241 (a subtype of mercury) both emits and then decays alpha particles at a constant rate into two neutrons of electricity. As these electric particles break apart, they ionize and absorb electrons from the oxygen and nitrogen atoms found in common or undisturbed air.

These free electrons that have been triggered by this form of (very miniscule, 1/5000th of a gram) radiation allows negative and positive charges to bounce back and forth between the ions which are attracted to the opposite radiation plates within the smoke detectors chamber.

If and when this current is ever interrupted, by smoke for example, it immediately sends a charge to the battery because the current has been lowered or changed and in turn triggers your smoke alarm.

This would essentially explain why Ionization smoke detectors tend to be so undesirably sensitive, or even ‘annoying’ for many people. But don’t go turning off or trashing your smoke-detector – it saves lives!

Infrared technology has been used for at least well over 10 years now—dating far back past many popular 007—James Bond Movies.

As we know as Americans, it’s likely that such technology existed far before it got into the hands of consumers, being utilized for various purposes through the government and its technology developmental and anti-warfare sectors.

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