How bright are mini LED's?

[Raven Industries]

I'm thinking of starting a project based on this video by Tested, except with LED lights instead of a microphone (if you don't want to watch the video, they put a microphone into the frame of some glasses). However, I can't find any data on the brightness of 3V LEDs in the 1mm-5mm sizes, specifically the ones found here. Does anyone know whether these are powerful enough to be practical?

 

 

[Camacha]

2 hours ago, KerbalSaver said:

Does anyone know whether these are powerful enough to be practical?

Yes. No. Tennis shoe.

It all rather depends on the requirements you are trying to meet

[steve_v]

5 hours ago, KerbalSaver said:

However, I can't find any data on the brightness of 3V LEDs in the 1mm-5mm sizes, specifically the ones found here.

If you get them from a proper electronics supplier, they will specify intensity in millicandela or lumens, if not a full data sheet. Your problem is that you are buying electronic components from a model shop.

[worir4]

I wouldn't buy them online unless you are buying hundreds of them. 

You could probably find them very easily at any local electronics shop or DIY store. The people there might even let you test one before you buy it so you can see how bright they are.

[cantab]

No data, but based on the descriptions those ones are probably not very bright, considering they're advertised as lighting small model rooms whereas I assume you want to light the real world. As mentioned, an electronics store should have better data and a wider range. For some context, a bike light would be about 5 candela or 300 mW per steradian. (Relating from those into lumens or other units is a little complex.)

[Raven Industries]

Thank you all for the advice. I'm not sure if there's an electronic shop nearby, but I'll look around for one.

[steve_v]

4 minutes ago, KerbalSaver said:

I'm not sure if there's an electronic shop nearby, but I'll look around for one.

I get very good mileage out of RS Components online, cheap as and they do free (and often overnight) shipping where I live. Might be worth checking if this applies to you too.

Edited January 20, 2017 by steve_v

[Nuke]

the datasheet usually reveals all. of course its practically impossible to determine the manufacturer and model of any led you have on hand, they just dont mark them at all. if you are buying new leds (or any electrical component for that matter), dont buy it from places that dont give you a data sheet, or at the very least a part number and manufacturer, so you can look up the data sheet on your own. then you have everything you need to know about it, from its optimal safe current rating to its optical output. of course its an led, you can buy a hundred of them on ebay for a buck, so you can just buy several kinds and test them yourself to see which ones are optimal for my application. also comes in handy to put more blinkenlights into my various projects. i just bought 50 uv leds for a uv curing table, i figure i can just put 20 of them in series (they will be edge lighting an acrylic panel with a diffusion pattern from a dead lcd screen, replacing the florescent tubes that normally do the same job) and stick a current regulator on them, in this case the difference in brightness means my resins will be curing 3 seconds instead of 30, either way it does what i want.

Edited January 20, 2017 by Nuke

[Camacha]

8 hours ago, worir4 said:

I wouldn't buy them online unless you are buying hundreds of them.

Why not? You can get lots of great components for less than peanuts. Even though you are right that buying small often does not make sense. If buying lots costs slightly more than buying a few, but still costs next to nothing, why not build a neat little supply for future projects?

[stibbons]

Practical for what? 

[Kerbart]

16 hours ago, KerbalSaver said:

I'm thinking of starting a project based on this video by Tested, except with LED lights instead of a microphone (if you don't want to watch the video, they put a microphone into the frame of some glasses). However, I can't find any data on the brightness of 3V LEDs in the 1mm-5mm sizes, specifically the ones found here. Does anyone know whether these are powerful enough to be practical?

 

 

Given the efficiency of LED's I would check the power consumption in the specs, that would seem to be a pretty good indicator of the amount of light they produce. Size is pretty irrelevant I think. I have a flash light with a 3x3mm element that can light up an entire room.

[worir4]

2 hours ago, Camacha said:

Why not? You can get lots of great components for less than peanuts. Even though you are right that buying small often does not make sense. If buying lots costs slightly more than buying a few, but still costs next to nothing, why not build a neat little supply for future projects?

If the OP wants to find out how bright it is then they would be better off trying it out before getting some. Also the delivery charges would probably be higher than the price of the LEDs 

[Raven Industries]

3 hours ago, Kerbart said:

Given the efficiency of LED's I would check the power consumption in the specs, that would seem to be a pretty good indicator of the amount of light they produce. Size is pretty irrelevant I think. I have a flash light with a 3x3mm element that can light up an entire room.

That's pretty impressive for such a small element.

 

So, I think I'm going to check some local hardware stores to see if they have anything, and if they don't I'll check online.

[Camacha]

2 hours ago, worir4 said:

If the OP wants to find out how bright it is then they would be better off trying it out before getting some. Also the delivery charges would probably be higher than the price of the LEDs 

Buying from the internet often means no shipping charges. Also, paying two or three bucks for a handful of LEDs is hardly a gamble. If you value your time, going to the shops is a lot more expensive - which it is regardless.

[Shpaget]

You still haven't told us what you want those LEDs to do.

[Camacha]

16 hours ago, Shpaget said:

You still haven't told us what you want those LEDs to do.

LEDs be LED'in, I guess.

[Raven Industries]

16 hours ago, Shpaget said:

You still haven't told us what you want those LEDs to do.

Oh, they are meant to be attached to a pair of glasses and be used as a sort of flashlight. The power will come from a Altoids can that you can strap to your belt.

[Nuke]

some months ago i discovered that the fine people at printrbot sent me a reel of glow in the dark filament by mistake (id ordered clear). recently i discovered that uv leds can make the stuff glow instantly (rather than holding it under the light for a few minutes). so im kind of wondering if i cant run them at a very low duty cycle, overdriving them at about an amp, much like you do with ir leds. the low duty cycle gives them much cooldown time. i can generate the wave form with a 555 and an inverter. then i can stick a little glow in the dark lense cap over it. end goal is perpetual glow in the dark stuffs, and using very little power in the process.

[Shpaget]

9 hours ago, KerbalSaver said:

Oh, they are meant to be attached to a pair of glasses and be used as a sort of flashlight. The power will come from a Altoids can that you can strap to your belt.

Keep in mind that these LEDs have a wide viewing angle, meaning, meaning their effective range as a flashlight will be limited. Unless you populate entire rim of the glasses with them, I doubt you will get any usable light for outdoor illumination. They may be usable for desk work, if that's your thing.

However, unless you shield your eyes from them, they will shine into your eyes making it much harder to see the less illuminated areas.

5 hours ago, Nuke said:

some months ago i discovered that the fine people at printrbot sent me a reel of glow in the dark filament by mistake (id ordered clear). recently i discovered that uv leds can make the stuff glow instantly (rather than holding it under the light for a few minutes). so im kind of wondering if i cant run them at a very low duty cycle, overdriving them at about an amp, much like you do with ir leds. the low duty cycle gives them much cooldown time. i can generate the wave form with a 555 and an inverter. then i can stick a little glow in the dark lense cap over it. end goal is perpetual glow in the dark stuffs, and using very little power in the process.

Sure you can overdrive LEDs, keep the pulses short and check the datasheet for how hard you can overdrive them. If you are talking about 5mm LEDs, 1 A is probably too much.

For example, this LED has absolute maximum rating for continuous current of 25 mA and peak current of 100 mA for 10% duty cycle and <0,1 ms pulse width.

Forgot to mention, be careful with UV.

Edited January 22, 2017 by Shpaget

[Nuke]

9 hours ago, Shpaget said:

Keep in mind that these LEDs have a wide viewing angle, meaning, meaning their effective range as a flashlight will be limited. Unless you populate entire rim of the glasses with them, I doubt you will get any usable light for outdoor illumination. They may be usable for desk work, if that's your thing.

However, unless you shield your eyes from them, they will shine into your eyes making it much harder to see the less illuminated areas.

Sure you can overdrive LEDs, keep the pulses short and check the datasheet for how hard you can overdrive them. If you are talking about 5mm LEDs, 1 A is probably too much.

For example, this LED has absolute maximum rating for continuous current of 25 mA and peak current of 100 mA for 10% duty cycle and <0,1 ms pulse width.

Forgot to mention, be careful with UV.

thats good to know. i was going to just determine the max duty cycle experimentally. when you order 50 of the things its no loss to loose 2 or 3 of them in testing. the 100ma for 10% duty cycle is just the test condition as specified in the data sheet. but if i want to run my duty cycle way down at 1 or 2%, i might be able to push a lot of current in a short period of time. ir lights in things like remote control applications are usually transistor pumped at a really high current to maximize transmission range. heat can be handled by putting a large heat sink on each of the leads (such as a larger than neccisary pcb trace). so im going to have a multimeter measuring current and an oscilloscope measuring duty cycle. while i ramp down the dc and ramp up the current. find the point where the led burns out, and then back it off until i can find a stable steady state condition. i dont want to know what its rated for i want to know what it can do.

Edited January 22, 2017 by Nuke

[Shpaget]

No multimeter is able to measure transient current in sub millisecond period. Even if it was, humans can't read it.

But, since you say you have a scope, you can measure the voltage drop across a series resistor and calculate the current that way.

Keep in mind that repetitive high current can slowly degrade the LED and destroy it after a while. It mey survive your testing, only to die on you the next day.

[Nuke]

1 hour ago, Shpaget said:

No multimeter is able to measure transient current in sub millisecond period. Even if it was, humans can't read it.

But, since you say you have a scope, you can measure the voltage drop across a series resistor and calculate the current that way.

Keep in mind that repetitive high current can slowly degrade the LED and destroy it after a while. It mey survive your testing, only to die on you the next day.

good tip there, i kind of had some concerns that my el cheapo multimeter would have trouble reading it. i know some multimeters have a serial link so you can log readings with a pc, but i very much doubt mine has that feature. its pretty much a no frills manual ranging mm from china. my oscope on the other hand barely deserves the name, it was one of those kit scopes that you can get for $50, so its horrible. resolution sucks, sample rates in the very low mhz. it has a serial export feature that i never got working. il definately have to do some endurance testing. one thing im probibly not going to be able to do is verify the optical properties of the led, since most of it's spectra falls outside human perception. i know some leds will start to creep up or down the em spectrum when you start putting power through it that its not capable of handling. for example green leds will turn yellow when over powered, and then fail not too long after that. if it works il have some eerie as hell halloween lights towards the end of the year without resorting to cliche rgb strips that everyone seems to use.

Edited January 22, 2017 by Nuke

[Shpaget]

If that fails, you may want to look into higher powered LEDs. Ebay is full of 3W, 5W and 10W ones.

Or if you feel a bit more adventurous, there are those tritium glow sticks.

[helaeon]

It might be useful to look at how small head-lamps are made and what components they use. I have a tikka lamp sitting here on my desk, and the LEDs and reflectors are small enough you might be able to fit something onto a glasses frame. You might even be able to find a lithium ion battery pack that would fit in there too so no need for a power pack on your belt. Whole thing could be self-contained. All of the LEDs have reflectors built around them so I'm pretty sure you're going to need to build a housing into the frames to make it work right.