FOLLOWING HIGH INFRA RED EMITTING BODIES???

[HAPPY BOY]

HEY…HOPE EVERY ONE IS FINE..I WANTED MY ROBOT TO FOLLOW THE HEAVY INFRARED RAYS, EMITTING OBJECTS AND IGNORING LOW INFRARED EMITTING OBJECTS.. CAN I ACCOMPLISH IT USING INFRARED EMITTER/DETECTOR CIRCUITS?? OR ANY OTHER SPECIAL SENSORS WILL BE NEEDED PLZ GUIDE…THANKS..

[Soeren]

HEY…HOPE EVERY ONE IS FINE..I WANTED MY ROBOT TO FOLLOW THE HEAVY INFRARED RAYS, EMITTING OBJECTS AND IGNORING LOW INFRARED EMITTING OBJECTS.. CAN I ACCOMPLISH IT USING INFRARED EMITTER/DETECTOR CIRCUITS?? OR ANY OTHER SPECIAL SENSORS WILL BE NEEDED PLZ GUIDE…THANKS..

We like to help people when they...
- Aren't SHOUTING.
- Uses quantifyables rather than adjectives.
- Show an interest in their own causes, by Googling first and asking questions later, when they're hitting a wall.

Infrared rays are roughly the same weight, so assuming "heavy" is your term for powerful, as opposed to "low" (probably meaning weak), you still need to define the amount of infrared, as well as the wavelength(s), that you want to discriminate, or no man, nor Google, will be able to help you.

[HAPPY BOY]

@ thanks for providing with the guide lines of how to post in forums..

i don;t want to detect ir radiations of human body ( till 10 microns)

and also don;t wana pick up the sunlight that is ranging from (800 to 3200 nm)

thanks again...

[Soeren]

Hi,

i don;t want to detect ir radiations of human body ( till 10 microns)

and also don;t wana pick up the sunlight that is ranging from (800 to 3200 nm)

I'd assume that "till 10 microns" included "800 to 3200 nm"?
Perhaps you could tell what you want to detect, rather than the opposite?

A description of what you're trying to accomplish would make it easier to find a solution as well.

[HAPPY BOY]

hi.. i want to detect Mid-wavelength infrared ranging from 3 micrometere to 8 micrometer that  include flame , exhaust etc

and ignoring the human bodies / tables / chairs /sunlight ..

thanks

[Soeren]

Hi,

hi.. i want to detect Mid-wavelength infrared ranging from 3 micrometere to 8 micrometer that  include flame , exhaust etc

and ignoring the human bodies / tables / chairs /sunlight ..

No single IR sensor will detect flames while excluding other IR sources, but it's solved in pro-equipment by either UV/IR sensors that detects two bands and check the amount of each, to exclude other IR sources, or by eg. double- or triple-IR sensors that checks at 4.4µm as well as 1 or two bands used as reference (again to exclude non-flame IR).

Hamamatsu makes en UV only sensor for flame detection btw, but you only asked for IR, so that may be of little interest.

Those detector types are all expensive compared to a simple photo transistor, of course, so unless you need absolute perfection, you might wanna go with a photo diode and use software to distinguish the type of source its looking at and experimenting to find usable signatures for wanted as well as unwanted sources.

The above is for flames, I have no idea of what IR band(s) an exhaust pipe delivers (but I guess it's very faint, compared to flames).
What are you making - a robotic dog chasing cars?

[HAPPY BOY]

hi,, wanted to ask how to plac the convex lens on an ir receiver??  waned to focus its rays to increase the range ?
thanks

[Soeren]

Hi,

hi,, wanted to ask how to plac the convex lens on an ir receiver??  waned to focus its rays to increase the range ?

That depends entirely on the focal length of the lens and whether you want it to be close to a parallel beam (place it in the focal point), or you want it to cover a wider area (place it closer to the lens than the focal point).

If you haven't got access to a LASER bench or similar, the easiest way to find the focal length of a lens is to use the sun and focus it on a dark grey or black target (to enable you to see the dot when in focus, a light surface will make it too bright to see) - this will be the focal length, as the sun is far away and can be considered a (near) single point, while a table lamp will give a false focal length.

Use the largest diameter lens you can, to get the most light at the receiver.

Even better... Mount the receiver backwards in a parabolic mirror (like one salvaged from a round car head lamp). This will get you more optical amplification, without the glass/plastic of a lens to dampen some wavelengths.
(Don't touch the mirror surface of such a reflector, trying to polish it with even the softest cloth will scratch the mirror).

[HAPPY BOY]

thanks alot..it was really helpful
one more query regarding your advice
 

"Even better... Mount the receiver backwards in a parabolic mirror..."                                                   

is it similar to the one as shown in the image below in the link? means in my case the ir receivers will be placed instead of lamps/bulbs....

[/img]

http://images01.olx.com.pk/ui/5/54/03/1269444033_82695103_1-Pictures-of--24V-LED-HeadLights-Aux-Lights-for-sale.jpg


and if i want to use multiple ir receivers ,each looking in different angle , shall i use a single lens/ mirror for all of them( as the lamps placed in the above image )  or differernt mirror/lens for each sensor?

thanks

[Soeren]

Hi,

is it similar to the one as shown in the image below in the link? means in my case the ir receivers will be placed instead of lamps/bulbs....

No, read this page:
http://www.edunewz.com/2007/07/testing-parabolic-reflector-with-light.html
It should help you get the idea.

and if i want to use multiple ir receivers ,each looking in different angle , shall i use a single lens/ mirror for all of them( as the lamps placed in the above image )  or differernt mirror/lens for each sensor?

If you want optimum focus, you need one for each, but read the article, it will be very informative

[waltr]

Consider using a flashlight (torch in UK talk) reflector as the 'telescope' optical element for the IR sensor. This works just like the diagrams in Soeren's link.

[HAPPY BOY]

it was really useful to read that..

however i did  use an alluminium foil present at base of a pringles cylinder, i cut out a piece of 4.5cm *4.5cm , and placed my sensor at its focus that is 0.222cm using the formula ( y = ax^2  ; y being the folding plane),  but did not get any reading (voltage)..

however without the aluminium plate , sensor was giving output. i wanted to ask may be the aluminium foil acts opaque to  the radiations or  have i used the correct material for parabola reflector??
or  have i placed the the sensor at the  wrong focal length??

thanks

[Soeren]

Hi,

however i did  use an alluminium foil present at base of a pringles cylinder, i cut out a piece of 4.5cm *4.5cm , and placed my sensor at its focus that is 0.222cm using the formula ( y = ax^2  ; y being the folding plane),  but did not get any reading (voltage)..

I don't know if Pringles cans vary between countries (I'd guess not), as all the Pringles cans I've seen have a flat steel bottom and a waffel-patterned matte alu-foil as top seal - neither would work as a parabolic mirror.
What do you mean by 4.5x4.5cm? A square?
What do you mean with "folding plane?
Where did you find the formula and what does a and x stand for?
A focal length of 2.2mm sounds very wrong.

however without the aluminium plate , sensor was giving output. i wanted to ask may be the aluminium foil acts opaque to  the radiations or  have i used the correct material for parabola reflector??
or  have i placed the the sensor at the  wrong focal length??

My guess is that it's either the form or the (wrong) focal point. The material may not be optimum, but it should still help somewhat.

Best way to quick-test a parabolic mirror is by looking into it (keep it perpendicular in bot x and y, to an imagined line between your face and the mirror) at arms length and holding a lit cigarette at the imagined line, slowly moving it back and forth until you feel the intense heat in your face (with eg. a 20cm mirror, this can be quite a lot).
In case you're a non-smoker, point a lit LED into the mirror until you see it filling the entire diameter - that will be relatively close to the true focal point.

If you can't find a real parabolic mirror, you could cut around a third of a sphere (ball shape), which means you get two (or 3 if you cut them slightly smaller) and cover the inside with aluminum foil ("polish" the wrinkles out after gluing). This time of year is ripe with cheap hard plastic spheres (depending on your country of course).

Focal distance of such an off-cut will be half the diameter of the sphere, no matter how large or small sections of the discs you cut.

Larger diameter mirror will give more signal and larger dimeter spheres will have a longer focal distance.

Most of all... Experiment, experiment and experiment - that's the fun way of learning