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Author Topic: op amp circuit for ir sensor  (Read 5104 times)

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Offline aruna1Topic starter

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op amp circuit for ir sensor
« on: January 29, 2009, 06:09:16 AM »
hello,
can someone give me a op amp circuit diagram which i can use to amplify signal of my IR sensor.i use analog signal out put of sensor to read IR intensity so op amp circuit should give analog output according to its input and should use single power supply (that is like +5V and 0V not +5V and -5V)
hope you understand what I'm saying.
thanks
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Offline Soeren

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Re: op amp circuit for ir sensor
« Reply #1 on: January 29, 2009, 11:22:20 AM »
Hi,

A few details are missing, please provide them to make it possible to help you:
 - What is the name/type number of the sensor?
 - How much gain do you need?

Any particular reason that it must be an op-amp?
What are you planning to use it for?
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Søren

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Offline aruna1Topic starter

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Re: op amp circuit for ir sensor
« Reply #2 on: January 29, 2009, 11:46:56 AM »
it is a normal ir sensor.
I'm trying to make flame detector.
i was able to detect flame using IR sensor i have.I used darlinton couple to increase sensing distance.but the distance i get from it is not enough so i was thinkin if i use Op amp i coud increase sensing distance.I need to make a sensor that can detect flame for abt 4-5 meters.thanks
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Offline Soeren

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Re: op amp circuit for ir sensor
« Reply #3 on: January 29, 2009, 03:13:59 PM »
Hi,

It's like if I ask you:   How many fingers am I holding up now.

You really need to post the type number of the sensor if you want a serious answer and "detect a flame on 4-5 meters" doesn't say anything on what gain you'd need as none here have got psychic abilities.

I assume it's a pyroelectric sensor of some kind (possibly the kind with one window blinded), but there are lots of them, so please post its type number - and if you don't know what gain you need, at least post what voltage you get from it when pointed towards a flame (before being amplified by the transistor you use now).
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
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Offline HDL_CinC_Dragon

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Re: op amp circuit for ir sensor
« Reply #4 on: January 29, 2009, 03:16:10 PM »
Im assuming youre using one of the Sharp IR Rangefinders and covering up the IR emitter side of the pair? It would help to know what the model number of the device youre using is.
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Offline paulstreats

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Re: op amp circuit for ir sensor
« Reply #5 on: January 29, 2009, 04:10:51 PM »
or an IR photodiode / phototransistor (in which case youll need a hell of a lot of boosting).

If it were me, i would boost it with a transistor then use a voltage divider circuit.(basically use a transistor and 2 resistors make sure 1 of the resistors is a potentiometer so you can adjust until you get what you want).

Also theres really only so much that you can boost some things (especially with light sensors where you get a lot of interference from other sources. eventually you end up boosting the interference as well as the correct signal)

Offline Soeren

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Re: op amp circuit for ir sensor
« Reply #6 on: January 29, 2009, 05:34:43 PM »
Hi,
or an IR photodiode / phototransistor (in which case youll need a hell of a lot of boosting).
[...]
especially with light sensors where you get a lot of interference from other sources.

He wants to detect flames, not light, so if he hasn't got a pyroelectric sensor, he's plain out of luck, as neither photodiodes nor Sharp IR-rangers will do any good to that end.
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
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Offline paulstreats

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Re: op amp circuit for ir sensor
« Reply #7 on: January 29, 2009, 06:00:45 PM »
Fire gives off IR light. lots of IR light.....

If it does turn out to be a PIR sensor, most devices have the following op-amp TS27L4ID
« Last Edit: January 29, 2009, 06:58:13 PM by paulstreats »

Offline aruna1Topic starter

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Re: op amp circuit for ir sensor
« Reply #8 on: January 29, 2009, 07:35:31 PM »
well i use normal IR sensor unit.it has no number.electronic parts shop has only these IR sensors and it can detect flame.its not a PIR.
about gain wel i dont know thats why i need a OP amp circuit with suitabe values
thanks
ps.I'll try to attacch photo of IR sensor

« Last Edit: January 29, 2009, 07:51:29 PM by aruna1 »
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Offline Soeren

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Re: op amp circuit for ir sensor
« Reply #9 on: January 30, 2009, 04:17:16 AM »
Hi,


Aha, what you've got is a common photo diode - not really sensitive to flames compared to a pyroelectric device (which I would advice you toward).
A PIR (Passive InfraRed) unit, which is a complete circuit, contains a pyroelectric sensor (of which many types exists).

This pyrosensor can be used for flame detection http://www.acroname.com/robotics/parts/R1-442-3.html
(and this http://www.acroname.com/robotics/parts/R67-UVTRON.html is a UV (?) detector claimed for the same purpose, I don't have time to read it now though).
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Please remember...
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Offline aruna1Topic starter

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Re: op amp circuit for ir sensor
« Reply #10 on: January 30, 2009, 04:32:23 AM »
well PIR will begin to detect human motion
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Offline HDL_CinC_Dragon

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Re: op amp circuit for ir sensor
« Reply #11 on: January 30, 2009, 03:03:05 PM »
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Offline Soeren

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Re: op amp circuit for ir sensor
« Reply #12 on: January 30, 2009, 04:41:25 PM »
Yes, UltraViolet. My question mark was hinted at using that part of the spectre for flame detection, since I didn't have time to read the paper as I had a patient due (still haven't had time to read it).
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Please remember...
Engineering is based on numbers - not adjectives

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