LM35

[TirthankarMukherjee]

I need to detect a flame of a candle... from 5ft distance with no obstacles in front ... can this be done with Lm35 temperature sensor... I want to make a fire fighting bot...

thanks in  Advance...

[frasenci]

I think you can get better results with an Optical device.
At 5 feet , the temperature of the candle's flame would be not noticed.
But light will , specialy indoors.

Look at the attachment.

You can get the LDR alone too , ( less $$ )

Greetings

[TirthankarMukherjee]

Any other options ... ? Depending on LDR would be a huge problem ... the ambient light will kill me ....

[shailesh5]

i think you can do it with a infrared thermometer as we use it in my work to sense the temperature of motors from a distance of 4.5 meter but not accuarate as distance is long.
shailesh

[TirthankarMukherjee]

i think you can do it with a infrared thermometer as we use it in my work to sense the temperature of motors from a distance of 4.5 meter but not accuarate as distance is long.
shailesh

how much does it cost ? I live in India ... is it available here ... I don't think so ...

[Trishool]

I need to detect a flame of a candle... from 5ft distance with no obstacles in front ... can this be done with Lm35 temperature sensor... I want to make a fire fighting bot...

thanks in  Advance...

Do you want to measure its temperature? or just if the flame is there or not ? , It isnt going to be an easy task .

TS

[sheriefaly]

i think lm 35 will take some time to sense heat from this distance so use any light sensitive element

[shailesh5]

yhe infared themometer is from FLUKE company , its a bit expensive for what you are tring to do, i would suggest you to use a P I R its an infrared sensor which are used in motion detectors in alarms i  think u can u have it easily at ur place
http://www.mikroe.com/en/tools/motion/ 

see the link above
shailesh

[Trishool]

i think lm 35 will take some time to sense heat from this distance so use any light sensitive element

Very Crazy 

[TirthankarMukherjee]

yhe infared themometer is from FLUKE company , its a bit expensive for what you are tring to do, i would suggest you to use a P I R its an infrared sensor which are used in motion detectors in alarms i  think u can u have it easily at ur place
http://www.mikroe.com/en/tools/motion/ 

see the link above
shailesh

How can a PIR / motion detector help me to detect a flame ?? Are you saying to as the flame will flicker I will be able to know where it lies ??

Posted on: January 22, 2008, 06:54:23 18:54 - Automerged

Do you want to measure its temperature? or just if the flame is there or not ? , It isnt going to be an easy task .

TS

I need to detect it ... if flame exists  ... then I need to move towards it...

[Trishool]

I need to detect it ... if flame exists  ... then I need to move towards it...

I think this would be fit for you
http://www.hamamatsu.com/
http://www.acroname.com/robotics/parts/R66-R2868.html .
And If you have a little more budget use a CMOS CAM  along with a recognition software I take here that you are having a laptop interface? since you say nothing regarding your project.

Hope this helps!
Ts

PS: Please explain your project in detail HW , SW , to further help you better .

[maddoc]

I hope that I got your question right.
You want to make a bot that "senses" a small fire (from a candle) and directs itself to it and then take some action.
The easiest way (not the best, but cheap) would be to put some phototransistors (at least two on the sides facing forward - but with more PhT's you will get better results) on your bot in some tube, so the only lightsource will come from the front of the phototransistor. Then you could check which one gets the most part of the light, turn the bot faceward to the lightsource and move in that direction. When the light intensity is at a preset level (you have to test for this) then the bot is at the right distance to take some action - spill the water or blow the candle.

I have seen a project using 5 phototransistors used to face a big solar cell perpendicular to the sun trough the whole day, taking into account season changing. It had a 2D movement mechanism with stepper motors.

Hope this helps!
Caesar

[hemlig]

You might get some useful ideas from this link about building a suntracker
http://www.geocities.com/njbibin/robotics/suntracker.html

[TirthankarMukherjee]

I need to prepare a working model of a fire fighting bot... so the source of heat is in my hand ... if detecting candle becomes difficult .. I would use a room heater/hair drier ... so that I can detect the hot region ( or what realistically happens during a fire...) ... I ideas proposed by irvinos and maddoc is simply great ... can we have some more discussion on this new problem... ??

   I am trying to simplify the problem a little bit so that I can put  my source of heat behind some obstacles ... then my bot will avoid the obstacles and reach the goal ( heat).

[maddoc]

Hmm... LM35 definitely won't do the job then, it should be a pretty wild fire before it will be sensed, and until you will get LM35's temperature to increase all your obstacles will burn down.

Your best bet is sensing the fire's IR or light emissions with phototransistors (cheap) or getting a IR camera and software to track the fire (not cheap, more programming).

Remember, if you plan on detecting obstacles with IR then you have to stop searching for the fire during obstacle searching.

Maybe detecting visible light and IR at the same time is an even better solution.

Here is an article on how much IR emissions a fire has.

Caesar

[macitmucit]

Lm 35 is a heat sensor

[Trishool]

I need to prepare a working model of a fire fighting bot... so the source of heat is in my hand ... if detecting candle becomes difficult .. I would use a room heater/hair drier ... so that I can detect the hot region ( or what realistically happens during a fire...) ... I ideas proposed by irvinos and maddoc is simply great ... can we have some more discussion on this new problem... ??

   I am trying to simplify the problem a little bit so that I can put  my source of heat behind some obstacles ... then my bot will avoid the obstacles and reach the goal ( heat).

In that case you may use a PIR sensor
http://www.futurlec.com/PIR_Sensors.shtml
http://www.scary-terry.com/itw/pirsensor/pirsensor.htm
Its very low cost  and easy to use , you may also include an LDR to detect light , this  way you get both the required parameters.


Ts

[TirthankarMukherjee]

Can PIR sensor detect the IR from flame of a candle/ heat of room heater ... I knew it has filter that only scans for the human radiation ..

[Trishool]

Can PIR sensor detect the IR from flame of a candle/ heat of room heater ... I knew it has filter that only scans for the human radiation ..

It has a Fresnel lense . Its fabricated in a way that you can sense fast fluctuations in temperature. My bet is if it senses a fast differential temperature change as caused by a moving human , and you say you can burn more fire the fluctuation in the fire patteren will trigger the PIR sensor as it will cause fast fluctuation in temperature domain.

Ts

[maddoc]

You haven't yet mentioned how much you are willing to spend for this project, so we know what to suggest...

PIR is harder to handle, but take a look here for some explanations: http://www.glolab.com/pirparts/infrared.html and some project ideas too.
Caesar.

[vsmGuy]

Tirtha,

use a webcam and OpenCV to process the image. Send control data to bot through RS232.

Was this useful ?

Posted on: January 26, 2008, 05:40:52 17:40 - Automerged
Furthermore, if your college is funding you, try out this :

http://www.sunrom.com/index.php?main_page=product_info&products_id=363

The LM35 will not be much of help for this case I am afraid !

[Trishool]

Tirtha,

use a webcam and OpenCV to process the image. Send control data to bot through RS232.

Was this useful ?

Posted on: January 26, 2008, 05:40:52 17:40 - Automerged
Furthermore, if your college is funding you, try out this :

http://www.sunrom.com/index.php?main_page=product_info&products_id=363

The LM35 will not be much of help for this case I am afraid !

vsmGuy , Please explain me regarding OpenCV interface . I have never used but would like to . It would be helpfull if you explain how to setup this with a webcam I saw the link you mentioned http://sourceforge.net/projects/opencvlibrary/ .  But what procedures ae required to initiate it . Very nice free thing it looks like.

Ts