Hi all,
Can i get circuit diagram for fire alarm using thermistor?
I have attached one here.The output device is not only buzzer in my case but also LEDs and exhaust fan serially.So i thought of using PIC microcontroller(I need to use PIC) to drive many devices.Then what should i do to improve the circuit ?

Thanks

Attached Files

fire_alarm.pdf (73.7 KB, 52 views)

 

The circuit looks like a Schmitt trigger type circuit and your PIC input can be hooked up to the 555's reset pin 4, which is being used to shut off the astable that's used to drive the speaker.

I'm not sure I understand what this circuit is for... would it be easier to buy an off-the-shelf smoke detector and use that detector instead of ad-libbing one (the temperature one would detect fire a lot later than an ionizing or visible smoke detector.)

 

Detecting a fire by temperature isn't always such a bad idea, if you want to prevent a battery pack or motor from overheating but it's wrong to call it fire dection; the real term is fire prevention.

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