change mode of operation at night and day?

Discussion in 'The Projects Forum' started by kdar1987, Jan 14, 2011.

  1. kdar1987

    Thread Starter New Member

    Feb 5, 2010
    What can I use to make a ambient light sensor?

    For part of one of my projects, I want the LED light to change modes (intensity, flashing or other settings) when time is switched from day to night.

    At night it should be dimmer and at day it should be brighter (so it will stand out).

    I plan to use some small, inexpensive controlled to control the switching/operation....

    I am just not sure what I can use to do this detection? Do I use something like photodiode? or just photoresistor? And how can I adjust it? use few amplifiers?
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    By using "ambient light sensor" as a search term, you get over 8,000,000 results. One example is -

    Like all electronic cats, this one may be skinned in several ways. Besides the purpose made sensors, you can get a CDS cell that changes resistance with illumination. You will have to calibrate the resistance to the level of light (harder than it might seem), but that will work.

    TAOS makes several different sensors - light to voltage, light to digital, and ambient - They are inexpensive, and Mouser is a distributor.
  3. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
    Is this for a single LED indicator, or for an array, such as a sign?

    As beenthere stated, there are many different solutions to this, many of them depend on the load (number of LEDs/current).
  4. kdar1987

    Thread Starter New Member

    Feb 5, 2010
    It is for an array (most likely).

    I did check online and found few different circuits for it. But I wanted to ask here. Thank you for links to Taos, this might be more useful.