Comparison of IR LED's for brightness and visible angle - Page 1
Forum section: electronics / beginners

author: DivineChaos
author_rank: Regular Contributor
timestamp: January 26, 2016, 02:42:51 am
content: Hey guys, I have another thread here where I am seeking help regarding a project I have. What I wish to accomplish with this thread is a good selection of IR LED's to transmit a "beacon" of sorts for a new and much more effective Wii light bar.Three things I need:1. At a distance of 5 - 30 feet in a lit bedroom, a single "visible" "dot". By visible, I mean with an IR sensor, and by "dot" I mean, 1 single bright LED or a very small group of LED's that appear as one dot.2. Very wide view angle of about 140 deg on X and Y axis'3. Not a complete power hungry LED.I have searched on Mouser (where I intend on buying said LED's) and came up with a few options that I need your guy's help choosing which one is the "best" for the above conditions.http://www.mouser.com/Search/ProductDetail.aspx?R=APT1608F3Cvirtualkey60400000virtualkey604-APT1608F3CRadiant Intensity: 1.2 mW/srBeam Angle: 120 degIf - Forward Current: 20 mAVf - Forward Voltage: 1.2 VPower Rating: 80 mWhttp://www.mouser.com/Search/ProductDetail.aspx?R=APT2012F3Cvirtualkey60400000virtualkey604-APT2012F3CRadiant Intensity: 1.2 mW/srBeam Angle: 120 degIf - Forward Current: 20 mAVf - Forward Voltage: 1.2 VPower Rating: 80 mWWHATS THE DIFFERENCE BETWEEN THESE?!?!? ^^^^^http://www.mouser.com/Search/ProductDetail.aspx?R=VSMY3940X01-GS08virtualkey61370000virtualkey78-VSMY3940X01-GS08Radiant Intensity: 15 mW/srBeam Angle: 120 degIf - Forward Current: 100 mAVf - Forward Voltage: 1.44 VPower Rating: 190 mWhttp://www.mouser.com/Search/ProductDetail.aspx?R=APT2012SF4C-PRVvirtualkey60400000virtualkey604-APT2012SF4C-PRVRadiant Intensity:unspecified?Beam Angle: 120 degIf - Forward Current: 20 mAVf - Forward Voltage: 1.3 VPower Rating:unspecified?http://www.mouser.com/ProductDetail/Vishay-Semiconductors/VSMB11940X01/?qs=sGAEpiMZZMvAL21a%2fDhxMgS39dZB0E5U4kge4BJnrkDG3cihF8Fg3A%3d%3dRadiant Intensity: 1 mW/srBeam Angle: 150 degIf - Forward Current: 20 mAVf - Forward Voltage: 1.24 VPower Rating: 35 mWhttp://www.mouser.com/ProductDetail/Vishay-Semiconductors/VSMB10940X01/?qs=sGAEpiMZZMvAL21a%2fDhxMgS39dZB0E5USpFn81L0KTQYbLI6FSYgOw%3d%3dRadiant Intensity: 1 mW/srBeam Angle: 150 degIf - Forward Current: 20 mAVf - Forward Voltage: 1.24 VPower Rating: 35 mWthese appear the same with specs, but not physically?? ugh this is why I need helpOk so there you have it, quite a selection to choose from. I guess the hardest part for me to understand is what Radiant Intensity means, and the Power Rating.

author: alsetalokin4017
author_rank: Super Contributor
timestamp: January 26, 2016, 06:19:28 am
content: Well, the first two are different sizes. One is 2mm x 1.25 mm, the other is 0603. I'm not willing to go through the Data Sheets for the others to sniff out the subtle differences.Radiant Intensity is roughly equivalent to "brightness" and the units are mW/steradian. So it takes into account the area (or rather solid angle) over which the illumination power impinges.The Power Rating is... the power rating. That is, how much electrical power you can put through the thing without it melting down and letting out the magic smoke. The data sheet will tell you if and what kind of heatsinking is required to allow you to use that rated power level safely.

author: con-f-use
author_rank: Unknown
timestamp: January 26, 2016, 09:07:21 am
content: Sprites mod hasbeaten usto this idea. Him using 1A LEDs and all, you will have little luck with your measly sub-1W-LEDs.I made a projecting "sensor" bar for the Wii. It uses the Wii sensor bar connection to switch a transistor via an optocoupler. The transistor powers two 890nm NIR laser modules from aliexpress. They need an external 5V supply of 200 mA. The Wii doesn't deliver that much current. It also has an a micro and an infrared LED to control my sound system and movie projector (mainly switch it on and off). I think it turned out pretty well with its 3D printed case. You can see it in the picture below:From my experience no affordable IR LED is coherent and powerful enough for the job, at least if you don't have a highly reflective surface. I ended up buying 30mW laser modules from aliexpress for $ 6 each. They do a good job and the lense is adjustable so you can focus the dot if it's too dimm or defocus it if it's too bright. However these modules are cheap chinese ones, so they vary in real output power from seller to seller. I've seen 60mW rated that were less bright than mine. Also my 30mW are barely 1mW of light output, so no worries about burning you retinas.None the less be save,IR lasers are very dangerous, becauseyou don't see IR while it still harms your eyes. The closing reflex of you eyelid doesn't trigger, when a bright IR beam hits but the lenses in your eyes still focus the beam's power to a very small spot. So be sure of the output power of your modules before you use them.

author: mikerj
author_rank: Super Contributor
timestamp: January 26, 2016, 09:21:57 am
content: Quote from: con-f-use on January 26, 2016, 09:07:21 amI hope you measured the power output accurately...Why do you need a collimated beam for the Wii controllers? Surely that will greatly limit the angle you can use the controller at?

author: con-f-use
author_rank: Unknown
timestamp: January 26, 2016, 09:31:48 am
content: Thanks for your concern, one can't be careful enough with ones eyes. I'm lucky enough to be a physicist at the local university and measured the output in our labs. Also it's mounted over head and defocused.Because it's slightly defocused, and more importantly, because the surface it's projected to is rough, the angle is good enough. It's 4.5m from the projector to the wall. Four people can play (at about 2.5m from the projection surface) with comfortable distance between them and the Wiimote still picks up on the IR for every one of them.I had poor luck with non-lasing LEDs, they just weren't focused/bright enough. But I'd love be shown wrong here.

author: Zero999
author_rank: Super Contributor
timestamp: January 26, 2016, 09:57:58 am
content: What you need to look at is the total radiant flux.You don't have to drive the LED at full power. In fact, driving a high powered LED, at lower than the rated current typically yields a higher efficiency.

author: DivineChaos
author_rank: Regular Contributor
timestamp: January 26, 2016, 05:47:45 pm
content: Actually, my idea has not been implemented yet. First off, wireless. If you search around the Internet, the biggest problem with the wii light bar is the wire. Cats, big ass TV's and such. I personally own a 60 inch flat screen and the wii light bar is completely ineffective at a comfortable viewing distance. Projectors are another issue.Secondly, spacing of the IR emitters is nowhere ideal for screen size. It needs to be dynamic and capable of stretching 3 feet wide for 60 inch TV's and for that same TV, 3 inches above or below the TV.As far as power needed to drive the IR led's:Two tea candles emit enough light to work at almost infinite range. So I think a 100ma IR LED should suffice.Con-f-use you gave me a most excellent idea with the reflective surface phrase in your post. The wii remote uses an IR camera to pick up on IR "light". I wonder if you project an IR beam onto a wall or "reflective area", if the wii remote will "see" it.Time to experiment. Tonight I will take a small LED and point it at the wall to make A "dot" and test that theory. If it works, I have a solution

author: con-f-use
author_rank: Unknown
timestamp: January 26, 2016, 06:49:49 pm
content: Okay I might have misread you. I thought you wanted to bounce light off of a wall.Let me clarify:My current setup(the black box in my picture above) is located right on top of my movie projector. The projector projects its picture on the opposite wall. The IR lasers on top of the projector do the same.The IR light bounces of a wall before it is picked up by the wiimotes.Total light travel distance is 4.5m (projector to wall) plus 2.5m (wall to wiimote), so 7m. At this distance, 200mA IR diodes are far too dim to be picked up by the wiimotes. Trust me, I tested it with focused high power 5W IR-LEDs and they barely worked. For significantly lower travel distances the "bouncy" approach might work, though.As to your wireless idea:People havemoddedentiresensor bars to work with batteries. People also have constructed units with one led and a battery. Two of them can be spaced apart as far as you like, thus accommodating virtually all screen sizes. They each have a 10mA LED, which seems to be enough if picked up directly by the wiimotes, without the light bouncing of a wall. Usually these have a manual on/off switch. So really not new. What would be new is to activate them automatically when the Wii turns on (e.g. via wireless transmitter from wiimote to the battery powered minibars).

author: DivineChaos
author_rank: Regular Contributor
timestamp: January 26, 2016, 08:07:48 pm
content: OK now we're on to something. Bouncing the IR light off a wall works.So I'll take a lower power IR led and bounce it's light off an object (like a piece of paper) directly behind the sensor (most likely attached to it) and have that object be what the Wii remote "sees". So instead of a direct beam, it sees a dot.Then, mod the light bar plug to contain only a wireless beacon that signals the sensor boxes to remain in the ON state while receiving power,abd have the "beacon" pick up that signal.Now we need a low power consuming wireless receiver that picks up that signal from about 30 feet or so through a standard wall that a Wii may be behind.

author: mikerj
author_rank: Super Contributor
timestamp: January 27, 2016, 06:52:30 pm
content: Quote from: con-f-use on January 26, 2016, 09:31:48 amI didn't realise you were projecting them against a wall, I'd assumed they were going to be used the same way as the standard Wii barLots of 1550nm lasers here at work, so I'm always aware of the potential for eye damage.