Hmm, not exactly a flashlight but definitely DIY - LED dome light mod

Flashlight Modding and DIY Parts
1

I'm not entirely sure this is the right place, but I figured not many people would see it over in one of the other sub-forums.

Anyway, I modded the rear dome light on my Focus wagon a winter or two ago so I could get more light out the back of the car when I finished night rides. I've been meaning to do the same to the front ever since and a blown bulb provided the impetus.

Starting materials:

4 XR-E WW of unknown bin

3 12V lightbulb drivers (got a bunch of bulbs in a job lot)

A handful of spare optics, include a bunch of really funky "Ledil Strada":http://www.ledil.fi/sites/default/files/Documents/Application%20notes/Strada_lens_guide.pdf optics that JonnyC very kindly sent me

Some alu plate, small heatsinks, Dell computer back plate blanks (the ones that cover the expansion slots, v. useful things) and 4#40 nuts'n'bolts

What it used to look like

Driver for car dome/trunk lighting
2

making the heatsink/ mounting plate

see? Dell expansion covers are the shiz!

the back..

the front, with LEDs mounted

LEDs wired up, more or less (optic is just for testing)

drivers wired up. Took quite a bit of trial and smoke before my electronically disadvantaged brain figured everything out

now with all the heatsinks on and everything wired up. Took me forever to figure out why one of the side LEDs wasn't lighting up (went through a couple of drivers sadly) until I found an open break in one of the LED wires.

now with funky optics on. There's a Strada DN on the left most (driver) centre pair, a Strada T DN (asym) on the passenger side centre pair and pod (has a Carclo in the pic, but it was too focused so I changed it) and a Gaggione XM-L spot optic (from Ofroad'bent on mtbr) on the driver's pod.

all together (before I took it all apart again)

from the side

from the other side. The whole assembly is hot-glued in and doesn't move. Hopefully it'll stand up to long term vibration, although it's not going to fall anywhere if it does come loose and its in there fairly tightly.

Beamshots!!

All on 1s, AWB and no idea about aperture

Centre light on

Pretty decent Scooby colour rendition. Hopefully we'll be getting some of those brownies back too.

Passenger pod

driver's pod

all on!

The centre light is wired into the dimming circuit and so dims to off like the original light did, although it cuts out much sooner (I'm guessing the voltage drops below the Vf+overhead of the 2 LEDs in serial). It's a bit brighter than the original, I think (poor memory), but the back seat gets way more light now so the kids can see what they're doing when they get in and out of the car. Side pods are awesome, even if they don't get used much!

I also really like the Strada optics - they give a really nice smooth light and the asymmetric one does a good job of putting the light where it needs to be without a sharp cut off. I would have used one on the driver's side pod too if I'd had enough.

Another plus - never having to replace a dome light bulb again! Woohoo! That said, the 4 nights this took would probably cover about 10 years of bulb replacements :)

3

Very interesting mod! Thanks for sharing! It's good to "think outside (or beyond) the flashlight". So were you on your way somewhere and then remembered "Oh wait, get out of the car I need to get beamshots" which probably led to some very interesting looks!

-Garry

4

thanks! I loved the rear dome light (no more stepping on my bike by accident), but this one was quite considerably more involved with multiple drivers and the like.

No funny story about the beamshots sadly, just in my garage. My youngest had a halloween party today, hence the brownies :slight_smile:

5

Congrats to you. 4 days you say? Very hardworking

I probably would do this when I wasn't not so lazy (like 15years ago maybe). Now, when I change to LED, I just get one of these and got it over with.

http://dx.com/p/39mm-2w-9-smd-led-126-lumen-6500k-white-dome-light-dc-12v-51002

(NOTE: If anyone else are lazy like me, just make sure you buy the correct length bulb, there are several).

6

it wasn’t supposed to be 4 days :slight_smile: I agree, those SMD arrays seem pretty decent and it’s hard to argue with the price. I like mine more though :smiley:

7

Wow. Don’t turn that light on while you’re driving!! :bigsmile:

8

Oh, definitely the cheap array won't beat XR-Es in any way. No question. The SMD grid are just standard 5050s, not really bright, not much definition too (soft light), but sufficient to find your way around.

I probably would follow in your footstep IF I have a 12V emitter, and just direct-drive it straight with Fujik on the steel bar (or whatever heat-conductor that's hanging in the car). Removal of housing/installing driver/heatsink is just too much effort for me

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thanks! It does verge a little on the too bright side, especially if I’m tired or it’s late. Then again, actually being able to find stuff or see the kids seatbelt fasteners is a big plus :slight_smile:

The 12V XM-L easywhite would be ideal, although I’d worry about it blowing a fuse or melting some wires if it can suck as much current as it wanted from the battery. It would be blindingly bright if it didn’t though!

10

Sweet! I'm very glad you were able to actually put those optics to use. Better than sitting at the bottom of my garbage bin.

11

thanks Jon, on both counts - these optics really made it perfect. I can see how they’d be somewhat disappointing in a flashlight though :slight_smile: I owe you big time for these and the driver, if you ever want anything in exchange (Reginas, 18650s?) just let me know!

12

I'm actually pondering on the easywhite option. That thing will easily do 300+ lumens at 350mA. That's gonna be really nice & bright, and still won't drain too much battery. Standard 40Ah battery will run it for 120hours - plenty of time just in case one forget to turn it off.

A single 12V EZW emitter is $5 at goodluckbuy.

A standard one-mode 350mA driver is $6.20 for five at DX, or $2.20 for single piece shipped.
OR a cheaper option would be 2W 2.8ohm resistor, which will give ~350mA at 12.6V (engine off) and absolute max at ~800mA at 13.8V (engine running). Well within spec.

That's just around $7, for an XM-L 300lumens, warm white, 80+ CRI for the car. Sounds nice. I might just get off my couch and do this someday.

13

here’s one on eBay , which would save you $1 :slight_smile: I’d go for the driver option, if only because it’ll make heatsinking it easier, although if you can fujik it to the body of the car, that might not be a problem…

Don’t forget some kind of optic though, it’ll make the apparent size of the light much larger and will make for a more pleasant light (less glare, no chromatic shifting with viewing angle). There are a bunch of 45-60deg optics on eBay for not very much, probably cheaper than I could send you one of mine!