Saturday, September 13, 2014

Motion detector switch in Hidco Bhavan installed: another smart step

I was a bit surprised to see that the lights in my office chamber at Hidco Bhavan were not switched on when I pushed open the door this morning. But as soon as I entered and started going towards my table, the lights came on on their own for one half of the office chamber. When I reached my table, the other half too lit up. I was told that Chief Engineer (Elec) S P Chatterjee had installed these infra red motion detectors yesterday while I was in Delhi. This was based on a discussion taken in one of the recent weekly meetings where I talked of conserving street lights through motion detector devices. Here is a picture of the ceiling mounted device (there are two in two halves of the room):

Motion detector in Hidco
(the round one)
I looked up the web to understand how this works. Here is an excerpt from Howstuffswork:

The "motion sensing" feature on most lights (and security systems) is a passive system that detects infrared energy. These sensors are therefore known as PIR (passive infrared) detectors or pyroelectricsensors. In order to make a sensor that can detect a human being, you need to make the sensor sensitive to the temperature of a human body. Humans, having a skin temperature of about 93 degrees F, radiate infrared energy with a wavelength between 9 and 10 micrometers. Therefore, the sensors are typically sensitive in the range of 8 to 12 micrometers.
The devices themselves are simple electronic components not unlike a photosensor. The infrared light bumps electrons off a substrate, and these electrons can be detected and amplified into a signal.
You have probably noticed that your light is sensitive to motion, but not to a person who is standing still. That's because the electronics package attached to the sensor is looking for a fairly rapid change in the amount of infrared energy it is seeing. When a person walks by, the amount of infrared energy in the field of view changes rapidly and is easily detected "
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Today Finance Minister Amit Mitra, Chief Secretary Sanjay Mitra, ACS(Commerce) C M Bachhawat, ACS(Power) Gopalkrishna, Pr Secretary (Health) Malay De, Pr Secretary (IT) Satish Tewari, Pr Secretary (Finance) H K Dwivedi, Pr Secretary (MSME) Rajiv Sinha, MD WBIDC Krishna Gupta and others visited Eco Pak in the morning and held a meeting in Glass House. This was a follo-up meet of the industry-diplomat meeting of Hon'ble Chief Minister held on 11th Sep.
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A new bank branch opened at Hidco Bhavan compound today. This is a result of sustained efforts of CFO Samaresh Mitra. An earlier security building was converted into a two storied building and modifications made to make the ground floor suitable for banking. The ATM counter will soon be opened. A photo (courtesy Subhashis Gupta):
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Two clippings:
Ei Samay dt 12.9.2014

Times of India dt 12.9.2014


  1. The floor area ratio(FAR) in

    New york Downtown-10-15
    Los Angeles CBD – 13
    Chicago, CBD 12
    San Francisco – 9
    Bankok - 8

    As mentioned in the article the FAR in new town CBD is 3.5. Is it true?
    Low FAR reduces the traffic on the road. Some green space
    may be entertained if we can fixed low FAR but minimum building height.

    Is there any regulation so that the upcoming building in CBD may have
    some minimum height (say 80m).

    In some plots the FAR may be relaxed to 10-12 so that few highrise may shape
    the skyline from Eco park.

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