Light automation system

Discussion in 'Homework Help' started by holz1100, Apr 27, 2016.

  1. holz1100

    Thread Starter New Member

    Apr 27, 2016
    14
    0
    I have been tasked with designing a lighting system for the parking lot and security lights of a building. The requirements are as follows; the parking lot lights rely on insufficient ambient lighting but also rely on information given from an access control system. They are meant to turn off 2 minutes after a specific signal is received (eg 0v) from the access control system. The security lights are to remain on as long as there is insufficient lighting and do not rely on the output from the access control system. We have been told to use 1 light dependent resistor to detect ambient lighting and ne555 timers for timing purposes. Both lighting systems rely on the single light dependent resistor.

    We are not allowed to use microcontrollers or IC's that we haven't built ourselves.

    I am thinking that I will use a logic gate for the information from the access control which then somehow needs to start a 2 minute timer after the output becomes from the logic gate becomes 0. The parking lot light should be on before the 2 minute timer if there is insufficient lighting, but needs to be turned off after 2 minutes. The light needs to be able to come back on if the output from the control system is not 0.

    Any reading material, advice or circuit diagrams would be greatly appreciated.
     
  2. Dodgydave

    Distinguished Member

    Jun 22, 2012
    4,998
    745
    Two 555 timers or one 556 timer or one cd4093 chip with a relay can do this.
     
  3. holz1100

    Thread Starter New Member

    Apr 27, 2016
    14
    0
    Thanks for the response :) I was thinking that perhaps a timer delay before circuit turn on would work better and then I'd use two NOR gates - one to turn the timer on using feedback from the access system and one to turn the parking lot led on using feedback from the ne555 timer. Any idea on how i can setup the LDR so that it can turn on both the parking lot and security lights? Keeping in mind that the parking lot led will need positive feedback from the NOR gate as well as the LDR and I can only use one LDR
     
Loading...