What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

DIY LED strobes: anybody doing this?

Stewie

Well Known Member
Hi all-
I'm about ready to order the lighting for my RV4 and have been combing the forum for info on light, cheap DIY LED installs. DIY nav and landing lights look fairly straightforward, but so far I've only seen commercial LED strobes mentioned. Has anyone tried or looked into a relatively cheap, easy LED strobe package that would approach the strobesn'more Pro-4 system in price/performance?
http://www.strobesnmore.com/strobes-n-39-more-pro-system-4.html
I'm willing to put up with mediocre performance since a) I don't fly that much at night and b) with the way LED technology is moving forward, I figure I can probably replace them in a couple of years anyway with something vastly better.
Thanks,
Eric
 
Yep. I am.

I'm going the LED Nav light route, but while thinking about that, decided to experiment with LED strobes as well.

The usual installation of LED Nav lights is a 3-2-1 triangle behind a bit of aluminum and plexiglass, with a strobe or landing light in the opposite side. Since I'm going with DuckWorks landing lights in the leading edge, I'm going to have 6 LEDs on each side of the wingtip cutout, but "interlaced" somewhat, to give 3 Red-2 White-1 Red and on the other side, 3 White-2 Red-1 White.

The Nav LEDs will be permanently on, but the white strobes will be driven via a Picaxe micro controller and a transistor. That way, I can program literally any type of flash pattern I want, as often as I want. No results yet, as the LED are still in transit, but Google says 1 Lumen=1 Candela, and the aeroLEDs strobes are "only" >150 Candela, so I'm hoping to be able to show they're at least comparable to a factory product.

Hopefully, I'll have photos to show in the next fortnight or so...
 
Last edited:
Just a hint on Landing lights......... the HID's from planelights are made for RV's and are AWESOME :):):)
 
Should be easy

Should be no problem to make your own LED strobes. I'm planning on making my own position lights and strobes. Thanks for the 1 lumen = 1 candella. Brightness units sure are a mess making it very difficult to figure out what is what.

I will probably wire my strobes with a 555 IC to provide the strobe pattern. I'll probably use LEDs from Luxeon as well as one of their constant current sources.
 
I was doing the same research AGAIN yesterday and look what i found on the same site.

http://www.strobesnmore.com/strobes-n-more-e-series-hide-a-way-led-kit.html

My only concern is going to be the interfearance they might create. But for the price I have a feeling I am going to give it a shot when I get back home. Unless someone does it before me of course.

-david

Nice work Dave! I don't know how I missed these. Think I found my strobes! Thanks everyone for your input, and also to Rob for the lancair article. I'll try to post a followup on this once my lights are installed.
 
Last edited:
Should be no problem to make your own LED strobes. I'm planning on making my own position lights and strobes. Thanks for the 1 lumen = 1 candella. Brightness units sure are a mess making it very difficult to figure out what is what.

I will probably wire my strobes with a 555 IC to provide the strobe pattern. I'll probably use LEDs from Luxeon as well as one of their constant current sources.



KR and Tom-
From my understanding, lumens and candela are rather different measures: lumens is a measure of total light output, and candela is intensity. Wikipedia has a good explanation on both.
 
Last edited:
1 lumen only equals 1 candela if the 1 lumen is distributed into 1 steradian.

The mathematical relationship is Candela = Lumens/Steradian

A Steradian is a unit of solid angle. There are 2*PI steradians (6.28) in a hemisphere, so if you put 1 lumen into a hemisphere, you get 1/6.28 candela.
 
1 lumen only equals 1 candela if the 1 lumen is distributed into 1 steradian.

The mathematical relationship is Candela = Lumens/Steradian

A Steradian is a unit of solid angle. There are 2*PI steradians (6.28) in a hemisphere, so if you put 1 lumen into a hemisphere, you get 1/6.28 candela.
Thanks Dean,

If I've got that equation right, I should be outputting 6 x 310 lumens per strobe, into (roughly) 1/2 a hemisphere, I should be getting 1860 * (1/6.28) = 296 Candela?

If it doesn't work, I'll be first in line to buy a set of your strobes. ;)
 
My approach

I'm looking at a similar approach as Rob using CREE LEDs. The design will be driving 6 CREE XML 280 LEDS at 2.5A and should get close to 3100 lumens / 490 candela on the side and 1500 lm / 245 cd from the front. The strobes will be at less than 20% duty cycle using a simple 555 timer and 4017B decade counter for the strobe circuit. The position lights are CREE XPE devices and will put out 600 - 1500 lumens depending on the current. Does anyone see a problem with this design?

15ho46q.jpg
 
Last edited:
Wow, those would be some BRIGHT nav lights. I made mine with six Luxeon Rebel Star LEDs per side (~600 total lumens red, ~400 cyan) and they're impossible to stare at.
 
Bright lights

Wow, those would be some BRIGHT nav lights.

Yeah, I think that I'll be driving the position lights at 350ma ea. I may also dial the strobes back a bit during ground operations using a brightness toggle.

My main concern right now is off axis coverage of the strobes. I think I've got more than enough light with the 120 deg. radiation pattern, but we shall see.

Hopefully the parts will get here this week and I can test em out.
 
Well, I finally got around to testing my LED Nav/Strobe combination, and the results are alright, but not quite as impressive as I was hoping.

I'm using 6 LuxeonStar LED's per light and another 6 for each strobe, intermixed, so there's 3 Nav/3 Strobe in each cutout. The Green and Strobe's are being driven by 5 Ohm resistor's in strings of 3, with the Red LED's in a string of 6 through a 2 Ohm resistor.

The brains of the strobe circuit is a Picaxe-08M chip and a pair of NPN transistors. The Picaxe can do a bunch of stuff from controlling RC servo's to infrared transmission, GPS position fixing and more, but I'm simply using it as a timer and means of switching the transistors. The chip itself costs around $5, a little more for the transistors and prototype board and around $250 for all the LED's.

Here's a dodgy video of the bench-testing of the strobes. I haven't got them running independently as yet, so was simply completing the circuit myself, but that's on the agenda for tonight. And HERE'S a new video showing the package in its' current state before it gets all prettied up and installed when I get back from work.


EDIT 1: Well, it's now tonight, and I've finally managed to assemble the Nav/Strobe package enough to functionally test it on the bench(aka. the dining-room table). The flash rate is too fast for my liking at the moment, but because the rate is set by the Picaxe chip, it is infinitely variable, using just a few lines of computer code, written in Notepad and sent to the PIC. Takes all of 60 seconds to change it from triple flash, to double, to triple and a pause, to whatever you want.


EDIT 2: Well, it's now tomorrow and I've tweaked the code a little more, and corrected the strobe video linked above. The strobes now have a more defined pause between the left and right strobe pulses and a 1 second pause before repeating the cycle. Slowed the flash rate down a little as well and made the flash duration a smidge (techincal term:p) longer. I'm fairly happy with where things are at, although I'd be happier still if the strobes were a little brighter, but the numbers say they "should" meet the requirements nonetheless.

Here's the code that I've used to regulate the flashing. Write it up, export it to the Picaxe chip via a USB cable, plug in your transistors and off you go. It's almost idiot-proof, which makes it perfect for me. ;)
Code:
main: 	
high B.1 		; switch on output B.1
pause 100
low b.1
pause 100
high B.1 		; switch on output B.1
pause 100
low b.1
pause 100
high B.1 		; switch on output B.1
pause 100	
low b.1
pause 1000
high B.2 		; switch on output B.2	
pause 100 	; wait 0.5 seconds
low B.2 		; switch off output B.2
pause 100
high B.2 		; switch on output B.2
pause 100 	; wait 0.5 seconds
low B.2 		; switch off output B.2
pause 100
high B.2 		; switch on output B.2
pause 100 	; wait 0.5 seconds
low B.2 		; switch off output B.2
pause 1000
goto main 	; loop back to start


And some still images...Just the Nav lights
6535587345_8aa4b27916.jpg


And Nav lights with the strobes lit
6535611051_4ff7ce415a.jpg
 
Last edited:
DIY LED Position & Strobe Lights

I've starting to think about rolling my own LED position and strobes. From what I've read in the FARs I'm not sure about some of the solutions people have come up with. Let me walk through my thinking and see if everyone blows holes in it.

For the position lights I think I can do this with some red or green LEDs mounted on the wing tips flat surface. There are wide angle red and green LEDs of the correct color. You just have to figure out how much light you need at the various angles. I think this is doable, and I think some of the solutions shown on VAF probably could comply with the FARs.

The strobe are a more difficult problem due to the wide angle of light requirement. If the LEDs are mounted on a single plane I don't think they can meet the letter of the FARs. This is because the requirement is for an even distrubution of light with respect to horizontal plane. I've looked at several LED strobes that are on the market and you'll notice that they have had to mount the LEDs in several different planes. I think this is required due to the LEDs not being able to distrubute light evenly as the xenon type strobes do. I'd be interested in comments from others about this. I would love to be able to use white LEDs on only the two planes of the wingtip cutouts. For the tail strobe Aveo puts the LEDs on three surfaces to get the coverage is required.

So what does everyone think about all of this? I'm certainly not an expert on the FARs, but I did at least print them out and attempt to understand them.

Oh one more thing. Does anyone have a cad file for the shape of the RV-7 wingtip cutout surfaces?
 
Last edited:
DIY LEDs

Hey All,

I guess I'm not the only one who agonized over this. I did a lot of research a while back and found all kinds of ideas. I used some, and made up some of my own. I ended up finding everything I needed on a popular auction site. You'll have to look through pages and pages, but everything you need is available. I found LED lights that fit in an automotive socket. 1057 or 1056 I think. Anyway they had "Superbright" units in all colors and sizes. There's also a strobe box for LEDs that's about the size of a matchbox. I wired that up and nearly blinded myself. It worked way better than I expected and graduated from experiment to installation. By the way I didn't do this to save money. I did it to save weight. Lighter wire, lighter strobe pack, smaller alternator (SD20), etc. On that note I decided to have strobes only on the tail (2 wires total). One in the original location and one on the top of the Vstab in a plexiglas lens that replaces the fiberglass fairing. So far the grand total for the lighting system was about $100, not including landing/taxi lights (still undecided on that).
 
LED Navs and Strobes

I am building some at the moment (well my mate is for me) and the package will have basically 6 strobe CREE LED's per side, and 12 RED/GREEN nav LEDS per side.

They will be mounted in the wingtips with reflective perspex on each face allowing for some 'bounce'.

The costs of the LEDs is quite expensive, however, given the outputs and the comparative products, it will be excellent value for money.

LEDs are definitely up to the challenge and I basically can't look at one, let along 6 strobe and 12 coloured.

Once Paul has finished his building, I will post some pictures. I have reviewed this 'forever' and the layout is unobtrusive and efective. We are looking at packaging these up as a kit so standby...... ;)
 
Well I decided to do some preliminary work on building my own. After some investigation I found some LEDs that appear to be suitable for this application. I ordered a few red, green and white LEDs with a very wide veiwing angle. I've gone throught the candela calculations per the far so I think I know the number of LEDs that are required. I purchased a couple of the star boards as a test. As soon as I get the rest of my order I'll try doing a more complete test.

I had a question to those of you who have used the mirror acrylic. Have you seen any discoloration of the plastic? It seems that most of this type of material is not UV resistant. If anyone found some I'd appreciate the link.

I'll give everyone an update when I have some more complete information.
 
At work we just installed some LED strobe flashers for the back of the snowplow dump truck they are definitely directional not very bright once you get off to the side of them.
 
LED Light Investigation

I just wanted to give everyone an update on my investigations into LED NAV, TAXI, STROBE lights.

First of all I'm still on the fence for the LED strobes. I now have spreadsheets that show the light distribution of 3 different LEDs. I have 3 different solutions. As far as I can tell LEDs are required in 2 planes to meet the FAR requirements. This is due to the fact that the light level must be consistient 360 degrees around the aircraft. The LED emission pattern drops off as you get more and more parallel to the plane of the LED. For the wingtip strobes I wanted a 90 degree coverage so the light output needs to be consistent over a 90 degree angle. The LED light output is no where near this for LEDs in a single plane. You can approximate this by offsetting the planes of two or more sets of LEDs. After going through this exercise I now understand why the commercially available solutions cost so much. Even to DIY it adds up.
I'm continuing to work on this, but I'm still not sure its work the effort.

The NAV lights are a different story. I found some LEDs that only require 4 LEDs to provide sufficient light levels and meet/exceed the requirements of the FAR. These LEDs can be mounted on one plane surface, and this creates the simplest solution I could envision for the NAV lights. I've taken Luminance readings with a cheapo meter that I bought from Amazon so I've verified that this solution will be acceptable.

For the Taxi lights I've ordered the SSC P7 stars and the reflector assembly. I'm waiting on that delivery now from Dealtime.

Once I complete my testing I plan to build a controller card to run all of the LEDs on each wingtip. That design is basically done, I'm just trying to complete all of my test measurements before I proceed with that board.
 
I think some people have tried doing this by adding a reflective surface to the opposite one of the cutout surfaces. The difficulty I see is getting the light to turn 90 degrees. I do agree that you could build some sort of reflector that took part of the light and redirected it. I don't think it could be as you have shown or as with the opposite surface of the wingtip cutout to be fully compliant with the FAR. I would think the light would have to hit the reflector at more like a 45 degree angle. While this could be done its too complicated for what I'm envisioning for my setup. The simplest DIY strobe solution still seems to be a standard (non-LED) strobe arrangement.
 
DIY LED's

rapid_ascent,
Let me know what you come up with. I am working on the early stages of the same thing and have some ideas. Definitely will be driving the LED's with an chip, not just resistors. putting together strobes, nav, taxi and landing lights.
 
I ordered some separate strobe bulbs from strobesnmore. They are on the way. I could have made some LED strobes, I figured out how to do it, but I decided I was just making work for myself. Its better to building the plane than building something that can easily be replaced with a couple of $30 bulbs and a power supply.

Sometimes we need to remind ourselves when we are getting off track. Even if it would be cool.:)
 
I ordered from Strobesnmore the following
http://www.strobesnmore.com/product_info.php?products_id=1548
http://www.strobesnmore.com/product_info.php?products_id=1318

First is for the tail, second for the wing tips. I will post results when I get them installed. Plan is to build the NAV and Taxi/Landing lights.

I looked at the second unit in your list a while back; I found that while it seemed pretty bright, it was (subjectively) not as bright as a traditional Xenon strobe head. The real deal breaker, however, was the RF it emitted. It was bad enough to break squelch on a handheld comm radio from 30 feet away - and this was just from running on a bench!

Perhaps they've been updated since, but I'd urge/caution you to check for RF prior to installing them in the airframe or anything like that which may be harder to undo later.
 
LED strobes made for cars...

I suspected that LEDs made for cars might not be shielded to prevent RF interferance. I am NOT an EE nor do I pretend to even understand what I just wrote, except; I know I can't have squeals and interference coming though my headset. Has anyone actually successfully installed a non-aviation LED system in their plane, and how did you deal with the noise problem...assuming there IS one?:confused:
 
DIY LED Strobes/NAV

+1 on the above post. As an avionics guy, I am concernes/very interested in learning about the RF from these 'non-aircraft' LED's. I LIKE the 2nd ones listed from strobesnmore, but won't tolerate the feedback and squeals. If they do squeal, is there an easy shielding solution? IF there isn't any feedback/squealing, I WILL be buying these.

Please keep us informed with your progress!

Thanks,


Gregg
 
Back
Top