This thread is for anyone working on personal projects to share their progress, and hold themselves somewhat accountable to a group of peers.
Post your project, your progress from last week, and what you hope to accomplish this week.
If you want to be pinged with a reminder asking about your project, let me know, and I'll harass you each week until you cancel the service
Jump in the discussion.
No email address required.
Notes -
There's a lot of good information on the WLED discussion boards (and, unfortunately, Discord). If you want to skip the programming side, WLED as a program is also pretty strong, if not necessarily well-documented.
Most of the NeoPixel/DotStar (or simple one-channel RGB 'mood lighting') strips intended for direct Arduino use will cap out around 60 mA per LED, simply because that's the cheapest and easiest configuration for the chips. Adafruit has some ultrabrights, but they're a nightmare of a form factor and probably too bright for what you're doing, even in the day. If you're willing to print out your own circuit boards, getting big LEDs onto a WS2814 chip is an option, but soldering the big heatsinks those LEDs come with onto a flexpcb is not an easy task, even with specialized tools.
Unless you're willing to deal with individual heatsinks on the ribbon, the easy tradeoff is just going with more LEDs in a smaller form factor. You can get individually-addressable ones up to 120LED/m this will have almost four times the brightness of a 30LED/m cheapo strip, along with better resolution. The WS2814s or APA102s are usually going to be the brightest in a given form factor. Going to higher voltages won't get you that much extra brightness, but it will have an impact and drastically simplify the wiring for even moderately-sized runs due to voltage drop issues, so 24v is probably the easiest to do with a 'normal' setup. This does significantly complicate the driver board, though.
Circuit-on-board options would be even brighter, but they're generally not going to have as high a resolution, and a lot of COB boards can only address 'zones' of multiple LEDs (sometimes over an inch per zone, which is how these COB strips advertise such high LED/m values). That said, do look closely at any purchase option; even 'standard' neopixel strips on are often zone-based (cfe here at 120LED/m and 20 zones/m, or here at 896 LED/m and only 16 zone/m). Low zone density will usually result in lower brightness when compared to a (admittedly often theoretical) strip of the same LED density.
Depending on the complexity of your intended LED patterns, this may or may not be an acceptable tradeoff.
WS2815s are always going to avoid zones and can be found in much higher density, but they're individually much less bright (at the benefit of being much more power-efficient) and only go up to 12v, along with having higher passive power draw. If you need a lot of detail and don't want to have to fuck with 24v power, the 300+LED/m strips might be worth looking at. I'd still recommend grabbing a sample unit and making sure it's bright enough.
Okay so if I was willing to forego individual addressing of LEDs, sounds like COB lights would be a good way to go?
I was imagining creating a 3D model of where every pixel was and being able to do a really sophisticated animation based on that (e.g. a pulse starting at some center like my vest and radiating out to the edges of my helmet and bottom of my bike), but there's only going to be a couple of light strips per item (helmet, bicycle, vest) so I don't imagine anything too intricate will show up and I should just consider controlling the color of all strips on an item as a single unit.
Depends on whether brightness or fine detail are more important. I'd probably go with the fine detail option, with what you're saying.
Regardless of what you buy, most are going to be somewhere around 2-5 lumen/LED. You don't have to beat the sun to be visible, but as a comparison most floodlights run around 1200 lumens, and automotive turn signals around 500-900 lumens.
None of them will be visibly bright under full sunlight (compare automotive high-beams at 3200 lumens), and I don't think it'd be practical for any clothing you'd want to wear. I'd expect a good quality thin diffuser will at least change color or perceived shade under a 144LED/m WS2815 setup (napkin math says ~500 lumen/meter post-diffuser) under normal outdoor conditions, but it will be subtle regardless of what LED strip you go with. And if you're wanting that sort of sophisticated animation, being able to control individual squares rather than long strips seems likely to be a bigger benefit compared to just adding additional parallel strips.
(imo, even 'normal' LED strips you won't want full brightness at night.)
There are premanufactured flexible 'sheets' of WS2815s that may be easier to work with for something like a vest, if they have enough density and brightness for your task.
More options
Context Copy link
More options
Context Copy link
How do the drivers for these work? Is it the simple series string + a resistor you see in a lot of lighting strips, or does it use a current limited supply?
I've been wanting to set up a DC led lighting system because I'm so sick and tired of the crappy built-in bulb power supplies, but actually driving these things off a varying battery voltage is kinda difficult
NeoPixels (WS28xx), DotStar (APA102/SK6812/SK9822), and most circuit-on-board designs do their own current control for each (zone of) LED -- the only real challenges for implementation are making sure you don't have too much voltage drop (because current control can't adjust for input voltage below the forward voltage drop), and if so just running additional power connections to the middle of the strip. They're not great for room lighting because of the color quality, though, even the RGBW variants, and diffusers only help so much. They're designed for constant voltage drivers; using a constant current power supply can cause problems ranging from comm issues to drastically reduced lifespan.
Cheap RGB lighting strips will almost universally do the series+resistor thing, as will even some decent single-color room lighting. Constant-current drivers and LED strips built for them exist, but you're usually stuck with very specific lengths of LED strip as a result; unless you really need the extra brightness uniformity, I dunno that I can really recommend any.
If you're trying to work with battery voltage to a non-current-controlled output, I really recommend a buck-boost-buck voltage stabilizer. You can get 12v ones for small or mid-sized applications that will handle the full voltage range you want to run a lead-acid battery down to, and are good on output within about 5%. Only downside is that they don't like starting in <-10F cold temperatures.
I got a cheap 10A (<5A realistically) one of those, 24->12. I don't have any way to test ripple, but at least it'll be easy to see if it makes LEDs flicker. Some of the chineseium power electronics is amazing, some of it's absolutely terrifying.
It's weird that for all the problems AC LED lighting has, DC is somehow no better lol. Seems like that's true of a lot of stuff that you'd think direct DC would be good for.
More options
Context Copy link
More options
Context Copy link
More options
Context Copy link
More options
Context Copy link