PIR Sensor based Alarm


This Passive InfraRed Alarm system can switch on a Lamp or Alarm when it detects the heat from an object like moving person. The name PIR (Passive Infrared) is given to the sensor because it receives the infrared rays passively and do not emit any infrared ray. The lamp or alarm remains on few minutes depending on the mono time setting of the PIR Sensor used. Ready to fix PIR Sensors are available with Fresnel lens to increase sensitivity and to filter ambient light. Its range is around 5 meters at 45 degree cone angle.

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2011 in review


The WordPress.com stats helper monkeys prepared a 2011 annual report for this blog.

Here’s an excerpt:

The Louvre Museum has 8.5 million visitors per year. This blog was viewed about 140,000 times in 2011. If it were an exhibit at the Louvre Museum, it would take about 6 days for that many people to see it.

Click here to see the complete report.