February 20th, 2008 by Dan East
Motion Sensor, the red LED means it is sensing motionI just made a quick grocery run to the local Wal-Mart and noticed they have made some substantial changes to save electricity. The modification was immediately apparent as I strolled down the frozen isle and the freezers sprang to life, triggered by new motion sensors that switch on the lights when customers are near. The lights stay on for around one minute when triggered, and there are 6 sensors down the entire length of the isle per side.
These sensors save electricity doubly – first, less electricity is used to power the lights themselves, second (and possibly more importantly) the heat the fluorescent bulbs emit by staying on continuously is no longer warming the interior of the freezers, causing the power-hungry compressors to do extra work to remove that waste heat.
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