Society of Robots - Robot Forum

Electronics => Electronics => Topic started by: YoungGenius on March 25, 2010, 05:49:29 PM

Title: Fire Detection?
Post by: YoungGenius on March 25, 2010, 05:49:29 PM
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?
Title: Re: Fire Detection?
Post by: Hawaii00000 on March 25, 2010, 08:14:29 PM
It'd use and infrared detector like this (http://www.radioshack.com/product/index.jsp?productId=2049727) .
Title: Re: Fire Detection?
Post by: waltr on March 26, 2010, 07:04:28 AM
It'd use and infrared detector like this (http://www.radioshack.com/product/index.jsp?productId=2049727) .
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!
Title: Re: Fire Detection?
Post by: Pratheek on March 26, 2010, 08:49:05 AM
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!
Title: Re: Fire Detection?
Post by: Hawaii00000 on March 26, 2010, 10:28:25 AM
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.
Title: Re: Fire Detection?
Post by: SmAsH on March 26, 2010, 02:48:09 PM
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.
Title: Re: Fire Detection?
Post by: Soeren on March 26, 2010, 11:59:28 PM
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.
Title: Re: Fire Detection?
Post by: nottoooily on March 27, 2010, 03:32:07 AM
smoke alarm??
Title: Re: Fire Detection?
Post by: Soeren on March 27, 2010, 09:22:47 AM
Going off each day at dinner time ;D
Title: Re: Fire Detection?
Post by: aruna1 on March 31, 2010, 12:34:13 AM
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.
Title: Re: Fire Detection?
Post by: amando96 on April 08, 2010, 04:57:37 PM
http://www.sparkfun.com/commerce/product_info.php?products_id=9570 (http://www.sparkfun.com/commerce/product_info.php?products_id=9570)

bit pricy though