5 feb 1969 año - Battery smoke detector
Descripción:
In 1969 the first battery operated smoke detector was invented by Duane D. Pearsall. Battery operated smoke detectors let people put them in their houses without being wired in. Now people can put them in every room of their house. They also made it safer because if the power went out the detector still worked with the battery.
https://gvp5029.weebly.com/cultural-artifact--the-smoke-detector.html
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Technology Timeline
Inventions 1900-1990
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