How do you increase IR LED range?

[Electro132]

Hi,

I'm trying to find out how to increase the range on an IR LED. I know some methods like

- adding more LED's;
- increasing the voltage input (i.e. instead of using a 5v batt you use a 12 v);
- adding transistors to amplify the existing voltage input into its base (i.e. using a 5v batt could increase to 1 w); and
- Using a high powered IR LED. (Currently using a 5mm 880 nm max 150 mA)

I am using a 5v batt for my IR LED circuit and while the IR LED works i cannot seem to get any result. Also, this is part of my current project but since it was a topic that i needed to get a wider audience in i was thinking this would help.

I appreciate any feedback given. Thanks

 

[GreenGiant]

the only viable options are adding more LED's or using higher powered ones.

Unless the voltage ratings of the ones you are currently using are higher than 5V that is. If they are not then adding more voltage will just potentially blow them, even with controlled current.

 

[duke37]

As GG says, overpowering a led is not good.

You could use a lens to focus the radiation on the receiver. This could be a plastic Fresnel lens which is flat and lightweight. You will need to get a lens which will pass IR radiation. This type of lens is sometimes used in the rear window of a car to aid reversing.

You could use a parabolic mirror. An old car headlight will provide this.

Any concentration of the radiation will mean that there will be less radiation off centre.

 

[Mongrel Shark]

Lens mirror and brighter Led would be my first thoughts too. Depends what you have on hand.

A little bit more info could help, like is this for long range indoor use, or are you battling sunlight, in which case a filter might be what you need.

I am using a 5v batt for my IR LED circuit and while the IR LED works i cannot seem to get any result.

I hope your using a resistor with that 5v. What is the result you are looking for? Are you sending data? or just a beam that gets interrupted like shop door buzzers. How far are you trying to reach? 150ma with 5v should be pretty strong...

 

[KrisBlueNZ]

Use parabolic reflectors at both ends of the link with the LED(s) and photodetector at the focal point
Use multiple transmitting LEDs, each with a separate parabolic reflector
Use transmitting LEDs with a very narrow beam angle
Align the transmitter and receiver very accurately
Use LEDs with higher efficiency, i.e. more light output for the same current
Use a short pulse of the maximum allowable pulsed current part-way along each pulse
Reduce the duty cycle of the carrier frequency and increase the current
Fine-tune the transmitter carrier frequency to match the centre of the receiver's response curve
Infra-red filter on receiver

Edit: I assumed you're sending data or commands, like an infra-red remote control. Some of those ideas aren't applicable if you aren't. Describe your whole project in detail!

 

[Electro132]

A little bit more info could help, like is this for long range indoor use, or are you battling sunlight, in which case a filter might be what you need.

I hope your using a resistor with that 5v. What is the result you are looking for? Are you sending data? or just a beam that gets interrupted like shop door buzzers. How far are you trying to reach? 150ma with 5v should be pretty strong...

Well it is for long range indoor and outdoor use. I have taken into account oxygen dissipating any signal given. i am thinking of a range that is about 160 km or 100 miles.

Yes sunlight during the day will be an issue. What type of filter are you suggesting for a range of this sort?

Yes i am using a 33 ohm resistor in series. I'm not sending data yet just the signal. I figured this would be enough for now as i need to perfect or have near accuracy of the signal at that long range (or close to).

 

[GreenGiant]

Well it is for long range indoor and outdoor use. I have taken into account oxygen dissipating any signal given. i am thinking of a range that is about 160 km or 100 miles.

Yes sunlight during the day will be an issue. What type of filter are you suggesting for a range of this sort?

Yes i am using a 33 ohm resistor in series. I'm not sending data yet just the signal. I figured this would be enough for now as i need to perfect or have near accuracy of the signal at that long range (or close to).

100 MILES?!?!
For pitch black night time use (new moon, cloudy skies) you would need an array of like 1000 of the brightest IR LED's you can find, focused through a lens to even begin to come close to this, Im not even sure if you could do this easily with lasers.

For during the day? forget about it, there is no way youll be able to do it, unless its a very cold place, and its cloudy, even still you are looking at spending thousands if not tens of thousands of dollars setting something like this up.

Just so you know, even the tallest and brightest Lighthouses can only be seen at most around 20-25 miles, now this has more to do with the curvature of the earth than brightness, but anything farther than that will be almost too dim to see, especially if there is any fog or anything in the air.

I don't mea to burst your bubble but what you are trying to do is basically impossible, the reason they have fiber optic cables (which operate with IR most of the time FYI) is so that they can transmit data like this over long distances.

 

[KrisBlueNZ]

i am thinking of a range that is about 160 km or 100 miles.

LOL!
Yes, what GreenGiant said!

 

[duke37]

The RSGB in RadCom published some articles on IR range. With very sophisticated equipment, they managed several km. It was done at night and a telescope was used with lights to line up the sender and receiver. I may have a look at the annual indexes if I have time.

 

[duke37]

"More adventures in optical communications." Stuart Wisher RadCom May 2012 p40

Two way contact 117.6km
Wavelength 630nm

Other wavelengths used 850nm and 940nm

55km has been achieved in daylight using Phlatlight leds at 5.9A.

There is a Yahoo group UKNanowaves.

 

[Electro132]

100 MILES?!?!
Just so you know, even the tallest and brightest Lighthouses can only be seen at most around 20-25 miles, now this has more to do with the curvature of the earth than brightness, but anything farther than that will be almost too dim to see, especially if there is any fog or anything in the air.

I don't mea to burst your bubble but what you are trying to do is basically impossible, the reason they have fiber optic cables (which operate with IR most of the time FYI) is so that they can transmit data like this over long distances.

Actually i'm looking towards the 940 nm range. Ok let's scale back to about at least 1km in range. I'm thinking a high powered IR LED (possibly at 1000 mA) with a fresnel lens used as a window can at least increase its range. Either that or use a fiber optics tube with the lens.

 

[davenn]

Actually i'm looking towards the 940 nm range. Ok let's scale back to about at least 1km in range. I'm thinking a high powered IR LED (possibly at 1000 mA) with a fresnel lens used as a window can at least increase its range. Either that or use a fiber optics tube with the lens.

1 km ... you are going to need a IR laser. A normal IR LED even with lens focussing isnt likely to achieve the results you are expecting


Dave

 

[(*steve*)]

Actually i'm looking towards the 940 nm range.

For a minute there I thought he meant NINE HUNDRED AND FOURTY NAUTICAL MILES!

 

[KrisBlueNZ]

For a minute there I thought he meant NINE HUNDRED AND FOURTY NAUTICAL MILES!

LOL!

To the OP. Check out the references so kindly provided by duke37. This should give you an idea of what technology and effort will be required.

 

[Electro132]

"More adventures in optical communications." Stuart Wisher RadCom May 2012 p40

Two way contact 117.6km
Wavelength 630nm

Other wavelengths used 850nm and 940nm

55km has been achieved in daylight using Phlatlight leds at 5.9A.

There is a Yahoo group UKNanowaves.

What are Phlatlight LEDS? Also are there PCB diagrams available? I'll look on google and see what i can find. Thanks guys

 

[duke37]

Have you heard of Google?

A PCB is the least of the problems, you will need very accurate positioning of the components and a lens with very low attenuation.

 

[Electro132]

Any ideas where i can get some globes or fresnel lens?

 

[brevor]

[Any ideas where i can get some globes or fresnel lens? /QUOTE]

Where are you located ?

 

[Electro132]

[Any ideas where i can get some globes or fresnel lens? /QUOTE]

Where are you located ?

Campbelltown, Sydney Australia. We have Jaycar here, but was starting to think that magnifyer shotglasses could be one method. What were your thoughts

 

[duke37]

Freznel lenses are used to help drivers see round corners. Look at truck accessory suppliers, also e-bay and green energy firms.
You will need a lens that passes the radiation that you wish to use.

What do you mean by a globe and shotglass?