Completed Project: Front of House LED lighting


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Hi Everyone -

I have made a blog post about my Teensy based project to control 380 LED modules under the roof soffit on the front of my house.

"In the spirit of why just do something when you can over do it this system computes the sunset time every day to trigger when the LEDs should turn on, a localized time system that understands time zones and daylight savings time schedules an alarm to turn the LEDs off, it has a luminosity sensor to fade in the LEDs during sunset, and a motion sensor to turn on the LEDs late at night. It is comprised of 10 handmade panels each 4 feet long that the span the entire front roof soffit. Each panel has 38 LED modules where each module has 3 super bright 5050 LEDs. To cap things off each module is individually addressable with an RGB value allowing for complex lighting patterns and eventually a light show"
Nicely done. I appreciate the detail you show. I was just talking about this with a friend of mine. Do you have video or other pictures of the RGB action?
Very nicely executed! It makes the stucco texture really pop. Also very nice work on making it look neat and unobtrusive when not in action during the day. Placing and removing all these little stickers must have been a test for your patience ;-)
Agreed! I likely would have been lazier , opted for the light strips sold in silicone tubing. Unlikely to be as durable but much easier to affix!!! I had not been aware of these modules, they look like the bees knees for outdoor applications.

Great project with a wonderful eye to detail. Congratulations!!!!
Thanks Guys - I was worried the stickers were going to be too much work so I did a test panel first and timed it. It only took about 10 minutes per panel to put them on and even less to take them off. However, I may have employed some child labor towards the end of the project. ;-)
Very Nice! Both the design and write-up. My house could use that treatment. Bad enough the house is in the woods, but above 48° north where even in the day the winter sun never clears the trees on bright days - some daytime mood lighting would often be welcome.

I bought some plastic tubed LED's the other year - seemed they were barely up when they failed in internal segments.

iambrentiam: Would you change the light density/layout for any reason? The spacing seems nice and uniform and makes good end to end wiring. Have you seen any of the 3 unit modules fail?

Looking at the ebay item I see each module has end mount screw holes.

<Edit>: These are the type of connectors you might have rather used?: Ultra T Plug Connectors Deans Style

<edit>: noob question - wiring the data line must feed through end to end. Must the power feedthrough or could the power lines have just jumped along one end?
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Thanks! That is pretty far north, wow!

I would definitely not go any denser if they are going to be close to the house, at that spacing it produces a lot of light, you could probably get away with going less dense but I do like the option of being able to produce more light and then just control the brightness through the RGB values. I did have one bad unit I discovered during testing which I just replaced easily enough. I bought a total of 500 of those modules so one failure in 500 is fine with me. In addition to the screw holes they have double sided tape but obviously I screwed in every module. On the connectors, I would definitely recommend those type of connectors, you would just need to use something to ensure they are outdoor suitable, the Apoxie Sculp could work but it dries very hard so something like Sugru ( could be better since I think it dries a little less rigid.

I believe the lines could jump along the ends if that would work better for your circumstances, you would still want to connect at least the ground in addition to the data line end to end to avoid any signaling issues. I did have a major uh-ho moment after I mounted the panels. I was using a discrete level converter (one of the bi-level converters from SparkFun). It worked on the bench even with all 10 panels connected if I lowered the clock to 400Khz which would have been fine. However, when mounted for whatever reason the LEDs had a ton of flickering and random colors on one side. So I switched to Paul's Octo adapter board, had a minor freak out when I forgot to put the clock back to 800Khz, but after I fixed that they worked perfectly. In hindsight I don't understand why the level converter worked at all at 400KHz but it did...

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IF it was me, I'd simply put a power rail on either end - POS on one side, Neg on the Other and run that the length of the soffit. You could use the vampire clamps to connect each light strip to the +5V and GND bus wires. Or go pro and use a piece of copper strip, drill and tap brass bolts and nuts, then use ring terminals.
Constantin - what is with your obsession of Vampires? :) ... oh these Automotive Wire Splice Clip? That would be cleaner - with less net wire/joints on the power rail - and make replacement less work as long as one end power pleases the electrons the same. One clip side feed through, the other a stub to two light units - faster to assemble too.

On Density: thanks - Dimming from bright better than too little light. An hour drive to Canada 'up here' - but growing up south of 40° is different than 48° by a full hour of daylight.
Ha ha ha. That vampire obsession is not necessarily mine... Offspring inspired the pig... And the French fry walking a calimari, the dragon, and (this year) the UFO and space turkey. At least I was able to inject a Teensy LC into the UFO. Made a really nice RGB light chaser.

So... Didn't know official name of automotive splice clamps! I used those clamps a lot for the 1-wire network around the house. They work reasonably well. They can be a bit unreliable unless you are very diligent re the clamping force and positioning of the clamp before clamping down.

I doubt however that those clamps are made in configurations where the wire being tapped can have a much larger cross section than the tapping wire. So for bus applications I'd likely resort to using a tapped copper strip and heat shrunk ring terminals. That combination is extremely rugged and very easy to serivce later on.

Another approach could be a merely drilled copper strip that has had wires soldered to it. Then use a butt connector to splice the LED units to it. That is much quicker than the drill and tap approach. Presumably, the failure rate is low enough that multiple replacements are out of the question.
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