what is the sensing range 5mm IR LED

[ravi.2k17]

Hi,

Can any one help me in telling the range of below given IR LED's range.
Is there any formula/data sheet to comprehend the range value ?

5 mm IR Transmitter and Receiver LED Tx Rx Pair Photodiode

Use this high power 5 mm IR LED Transmitter and Receiver pair to build wireless remotes for appliances, distance sensors, object sensors, colour sensors, line sensors, distance sensors, etc. Can be directly connect to a microcontroller, Arduino or Raspberry Pi with only a few current limiting...

www.probots.co.in

thanks

 

[KlausST]

Hi,

Range.. frequency range? Angle range? Distance range?
If distance: what signal? DC? Or AC?
Data communication or obstacle detect?
With aperture or lense? Which type, values?

Please don't post riddles.
Tell us all your technical informations about your application.

An IR LED sends out light. Theoretically the light goes endlessly?...

Klaus

 

[c_mitra]

Hi,

Can any one help me in telling the range of below given IR LED's range.
Is there any formula/data sheet to comprehend the range value ?


thanks

The question is badly asked: The IR travels to infinity (you can see the moon, the sun and the stars, right? They are bit far away) and should be possible to detect till the noise level of the detector falls below the signal. In this particular case, the IR led is modulated with a carrier frequency and the photodiode is set to detect this carrier frequency above a certain threshold (of amplitude= signal strength). Your question does not have a clear answer because you have not given the details.

 

[ravi.2k17]

The question is badly asked: The IR travels to infinity (you can see the moon, the sun and the stars, right? They are bit far away) and should be possible to detect till the noise level of the detector falls below the signal. In this particular case, the IR led is modulated with a carrier frequency and the photodiode is set to detect this carrier frequency above a certain threshold (of amplitude= signal strength). Your question does not have a clear answer because you have not given the details.

I have to make something like shown in below link using IR Tx/Rx but to support 30 meter range. my TX and RX would be 30 meter apart on a straight boundary wall.

BEN10M-TDT

Sensor, Photo, Through Beam, 10M Sensing distance, Light & Dark On, NPN & PNP Output, 12-24 VDC

www.autonicsonline.com

My intention is to make a similar anti-theft alarm. I know this can be achieved using IR LED and hence wanted to know what models of IR pairs should be used so that Rx can receive it without signal loss. How to select an IR component? What should I look into datasheet before selecting any IR component which can serve my purpose optimally ?

***I am completely novice in electronics. Just started to learn it as beginner. Hence my questions might not have complete details. Please feel free to ask what you want to know from my end to make my requirements clear.***



thanks.

 

[FvM]

The linked light barrier surely uses optics (lenses) to focus the light beam, you should do the same.

 

[c_mitra]

The simplest solution has been already given in #5. Use a suitable lens to focus the light on the detector. It does help if the detector has large active area. IR is tough to see (yes!) and alignment can be tricky. Most common glass and plastics absorb IR and you need to hunt for a suitable lens. Small dia and small focal length is helpful but can be difficult to align. It may be useful to temporarily replace the IR led with a red (and visible) led. If the LED power appears insufficient, use an IR LASER diode. Make sure the modulation is deep (close to 100%).

 

[ravi.2k17]

The simplest solution has been already given in #5. Use a suitable lens to focus the light on the detector. It does help if the detector has large active area. IR is tough to see (yes!) and alignment can be tricky. Most common glass and plastics absorb IR and you need to hunt for a suitable lens. Small dia and small focal length is helpful but can be difficult to align. It may be useful to temporarily replace the IR led with a red (and visible) led. If the LED power appears insufficient, use an IR LASER diode. Make sure the modulation is deep (close to 100%).

Is this you are taking about ? what model should i choose? what would be receiver of IR Laser diode?

Quikprof 808nm 300mW High Power Burning Infrared Laser Diode Lab : Amazon.in: Industrial & Scientific

Quikprof 808nm 300mW High Power Burning Infrared Laser Diode Lab : Amazon.in: Industrial & Scientific

www.amazon.in

 

[c_mitra]

Is this you are taking about ? what model should i choose? what would be receiver of IR Laser diode?

Laser diodes have low divergence and therefore longer reach. You do not need a lens with the transmitter but a simple lens at the receiver can be helpful. Any simple Si photodiode can be a decent detector. If higher sensitivity is needed, use a PIN photodiode. Most common photodiodes will show good response at 800nm. This wavelength is just outside the visible range but a faint red glow can be seen sometimes (this is not the lasing frequency). I am not suggesting a particular one but if you want to use this as the transmitter, it will work well over the intended distance of 30 m (perhaps will work upto 100m or more).

 

[BradtheRad]

I had success with a narrow-angle super-bright orange led. Shone a visible dot big as a dinner plate 20 feet away. My receiver was a magnifying lens 1 inch diameter focused on a photodiode. Easy to line up everything. No need to go with infra-red.

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As for putting a lens near the transmitting led... In my tests the type that works is large diameter, long focal length. Short focal length causes a vastly enlarged image at the receiving end, with the effect of dimming whatever illuminates the photodiode.

 

[c_mitra]

Short focal length causes a vastly enlarged image at the receiving end, with the effect of dimming whatever illuminates the photodiode.

The idea of using a lens is to reduce the dispersion. If you keep the source at the focal length, the image will be at infinity and the rays will be practically parallel. A short focal length lens (e.g., a low power microscope objective) can be placed close to the LED and it will collect most of the light (high NA) from the LED. If you have a lens with a longer focal length, then you have to place it further from the source and in the process will collect only part of the light (less solid angle coverage). Most LEDs have a built in lens (the top surface is curved) that produces a beam with a known divergence. However, if you are using a lens at the receiver side, then you should use a large dia long focal length lens (like a telescope) or a paraboloid mirror to catch as much light as possible. Modulation simply helps reduce the ambient light as background.

 

[FvM]

If laser diode, it must be eye safe. IR laser is effectively banned for open beam applications, and also laser power above a few mW. In so far the linked IR laser is just inappropriate.

 

[ravi.2k17]

If laser diode, it must be eye safe. IR laser is effectively banned for open beam applications, and also laser power above a few mW. In so far the linked IR laser is just inappropriate.

If IR Laser Diode is not safe then what would be better choice for making anti-theft alarm? As i have said earlier in the mail my boundary walls are 30 meter long therefore tx/rx should be 30 meter apart.

 

[KlausST]

Hi,

What's wrong with the suggested lens solution?

Klaus

 

[c_mitra]

You can certainly use a common red led diode laser pointer (they have less than 5mW output power and are widely available). Use as detector the common remote control IC package.