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  • Engineering Project Help - LDR security buzzer circuit

    linksy

    Member

    Updated: Oct 26, 2024
    Views: 1.2K
    Hello there
    I was woundering if anyone would be able to point me in the right direction with my project for college.
    I am doing a simple buzzer circuit using a light dependant resistor, 9v battery, BC639 transistor, a 1k resistor, a 10k resistor and a switch.

    I am mounting the components inside a enclosure with the switch and the ldr exposed on the outside. My idea behind it is to be used in a safe for security, so when the door is opened the buzzer sounds due to exposure to light.

    The concept im having difficulty with is finding a way to add some sort of button password combination in replacement of the switch, so that when the owner of the safe was to open it they could deactivate the buzzer and then activate it again after use.

    Im really no expert on this so go easy with me please

    Thank you
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  • cooltwins

    Member • Nov 21, 2009

    The concept im having difficulty with is finding a way to add some sort of button password combination in replacement of the switch, so that when the owner of the safe was to open it they could deactivate the buzzer and then activate it again after use.
    neither am i an expert in this field but i have done a paper in the concept of burglar alarms and in that to enable a user to deactivate it a control box is used.most modern burglar alarms incorporate this facility into the circuit -- the control box.
    1) The control box is hooked up to one or more alarm circuits, but it also has its own power supply.
    2) It monitors the circuits and sounds the alarm when they are closed or opened (depending on the design). But once the alarm is triggered, the control box won't cut it off until somebody enters a security code at a connected keypad.
    3) For added security, the control box is usually positioned in an out-of-the-way spot, so the intruder can't find it and attempt to destroy

    but to even delay this trigger there are some control boxes which have the facility of an entry delay
    There is a short delay to give the homeowner time to enter a security code that turns the system off.
    If the security code is not entered, however, the control box will activate various alarms.

    hope it doesn't confuse you and is of some help to you
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  • Tkot

    Member • Nov 23, 2009

    linksy
    The concept im having difficulty with is finding a way to add some sort of button password combination in replacement of the switch, so that when the owner of the safe was to open it they could deactivate the buzzer and then activate it again after use.


    im really not an expert either but can help with some links. there are #-Link-Snipped-#, <a href="https://www.electronics-lab.com" target="_blank" rel="nofollow noopener noreferrer">Electronic Projects, Embedded News and Online Community - Electronics-Lab</a>, <a href="https://www.projectsparadise.com" target="_blank" rel="nofollow noopener noreferrer">Projects, Thesis, Dissertation, Project Reports</a>. you can get some informations on keypad combination locks.😁
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  • reachrkata

    Member • Nov 27, 2009

    Perhaps this thread will help you with a simple password entry keyboard -

    #-Link-Snipped-#

    - Karthik
    😁
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