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Temperature Drop Trigger

  • 28-08-2014 07:57AM
    #1
    Ziycon
    Registered Users, Registered Users 2 Posts: 1,991 ✭✭✭


    I'm looking for some advice, I have a situation where when there is a sudden drop in temperature that a cctv camera will turn on or trigger.

    One of the requirements is that the speed at which the temperature drops is configurable, so it could be set at 1 degree per second or 3 degrees a second.

    I'm looking to build this from scratch from components (I have some experience in this regard so not entirely new to me) instead of buying existing devices as in the long run I could have many of these triggers in place and/or want to make modifications to them.

    Any help/advice on what components/parts I should use greatly appreciated.


Comments

  • #2
    backboiler
    Registered Users, Registered Users 2 Posts: 368 ✭✭backboiler


    Cheap microcontoller with ADC input + analogue temp sensor, e.g. PIC12F1571 (4x 10-bit ADC) with LM335Z. Total cost of 2, maybe 3 quid.

    If you're only interested in temperature change then the initial accuracy is irrelevant and you can just sample every so often and set a GPIO pin when your temperature slope condition is met.


  • #3
    Ziycon
    Registered Users, Registered Users 2 Posts: 1,991 ✭✭✭Ziycon


    Thanks for the backboiler, I'll look into these parts and give it a go. :)


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