Rav4EV LED Dome V2
(with programmable driver)
Yes, I am afraid it is true. My rear dome light is now software-controlled and programmable. Can it get any geekier than this?
It all started with a constant-current buck circuit, driving one LED. The first LED dome (V1) unit was a drop-in replacement for the stock bulb. V2 is NOT a drop-in replacement since it required substantial modification to the light fixture - and this is why I'm not offering them for sale! This incarnation of the driver (called uFlex - designed and built by a brilliant friend) is programmed to turn the light off after a pre-set time. I finally have the run-down protection that I have wanted all along! The benefits of this circuit are all tied to the flexibility offered by software control. We currently have it programmed to dim in eight steps, automatically turn off, wake up at the last brightness setting... and several other features that start to sound complicated. Once programmed, all of this is controlled with the single button (the red one poking through the lens). Additionally, there is a programming header on the circuit so new software can be added at any time. The bottom line here though, is that once you select the brightness you want, you really never need to use the button again. It simply works like a regular dome, being controlled by the door or light switch... with the additional benefit of battery rundown-protection if a door is left open, or the switch is left on. If I make another of these, I'll probably hide the switch under the lens.
I mounted two 1W emitters to a heat sink I made by sandwiching a commercial, finned sink between two aluminum plates for additional mass, which is then screwed to the fixture. The uFlex would not fit in the fixture, so I wired it remotely. The board is just poked up above the headliner, out of the way and out of sight. I put the circuit in an anti-static bag for protection. It ain't pretty when it is out, but it looks great when installed. This thing is now at least twice as bright as the stock light was. And WAY whiter. Yes, the front dome conversion is several version old now as well.
Here it is all buttoned up.
I discovered long ago that taking pictures
of light is damn-near impossible (at least for me), so use your imagination.
Now these are a bit ugly, I know. This is the
proto. I ended up toasting these emitters in my testing. The final "pretty"
version can be seen near the bottom of this page.
uFlex circuit on the leash.
uFlex circuit in the anti-static bag, ready
for insertion.
Poke the uFlex right up under the headliner,
and you're good to go.
Here you can see the round, black, finned heat
sink sandwiched between two aluminum plates for more heat-sinking mass. Two
1W emitters get surprisingly hot. And unlike incandescent bulbs, heat
is the ENEMY here. Reduces light output and life of the LED. The red/white wire
is the switch lead. Needed some slack so the lens could be removed.
OK, so then I had to rebuild the module after
releasing the magic smoke from one of the original emitters. Since I had it
back apart, I took better pictures of the circuit and of the heat sink module.
I have now affixed the emitters in the "star" configuration. This
adds even more heat sink, but it was a bugger to fit back into the light fixture.
I suppose this is now V2.1?
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