Fire Detection?

[YoungGenius]

How do I make a small sensor that I could put at the rim of a pot (over the stove) so that when it detects too much light it sets an alarm off?

[Hawaii00000]

It'd use and infrared detector like this .

[waltr]

It'd use and infrared detector like this .

This will only detect IR light modulated at 38kHz. It will not detect a fire under the pot which is want I believe the OP wants to do!

[Pratheek]

A cheap and simple solution would be to use Light Dependent Resistor(LDR) or a photoresistor. Search the internet for the circuit. It is quite a popular circuit and should be available.

You will also have to some how insulate the sensor from the flame, so the the parts themselves do not catch fire!

[Hawaii00000]

You could use an  IDR, but it go off from other souces of light. An IR detector will only sense IR which is given off by a flame. I'm not sure exactly what frequencies a flame gives of, but I don't think that wouldn't be to hard to find.

[SmAsH]

Yes, IR would work but that sensor blocks out anything above or below 38kHz which could cause problems. An ir sensor could work but it would need to be wide range.

[Soeren]

Hi,

How do I make a small sensor [...] when it detects too much light it sets an alarm off?

Many fire alarm systems include thermal detectors, as a quite effective means of detecting fire.
I don't know exactly what fire you wanna detect, the ones under the pot or those that may arise from forgetting your stew for too long (Which may sometimes only result in a glowing mass and black smoke).
In each case, a thermocouple bead could be a viable solution, as in any case, the temperature will rise rather quickly in case of a fire. Further, Thermocouple beads come in variants that easily cope with 1300°C.

[nottoooily]

smoke alarm??

[Soeren]

Going off each day at dinner time

[aruna1]

HI,
i made a fire sensor for fire fighting robot competition which won both 1st and 2nd places.
I used a simple IR detector(one like 2SD400 transistor bt only with 2 pins) and a differential amplifier.it works very well.only draw back is its sensitivity greatly reduces with sun light.

[amando96]

http://www.sparkfun.com/commerce/product_info.php?products_id=9570

bit pricy though