While the gold standard for colorful blinky projects are individually controllable RGB LEDs, the usual offerings aren’t really that impressive. Yes, a few hundred Neopixels, WS2812, or other RGB LEDs will sear your retinas, but what if you wanted blinky glowy stuff that is so over the top as to be an affront to whatever creator you believe in?
This is it. [Ytai Ben-Tsvi] created an individually addressable RGB LED called the Pixie that is perfect for all the times when you need something bright, colorful, and want to blind a few people in the process.
WS2812s and Neopixels are basically RGB LEDs with a small microcontroller tucked tucked away inside, and so far there is no design house or fab plant in China that is crazy enough to add one of these tiny dies to an already overpowered LED. To build the Pixie, [Ytai] took a bare RGB LED module and added a microcontroller – a PIC12FF157X in this case. It’s not exactly a powerful microcontroller, but it can handle the shift register-like function of an individually addressable RGB, and adds gamma correction, over heating protection (something necessary when you’re dumping this much power into a tiny board, and other safeguards for each individual LED.
[Ytai] is working with Adafruit to produce these Pixies, and although they’re rather expensive at $15 per LED, you won’t need very many to blind yourself.
$15 each?
Yup waaay too expensive. He describes 50 used on a burning man hipster jacket he made. Thats $750!!!
Seems like the aluminum PCBs for LEDs would be a good option here so you can leave them on longer. One of the cheap prototyping shops does one or two sided Al PCBs.
I wonder if drilling a hole behind the led and inserting a copper/aluminium plug with a bit of thermal paste would do the trick.
This guy has the right idea with the copper slug insert… https://hackaday.io/project/6874-powerpeg-thermal-management-system
It is not that uncommon to see a similar thing implemented in the PCB itself; several large vias under the thermal pad, which go out to the back side, which is ideally a copper plane. They get filled solid with solder during assembly, and act that thermal bridges to the back of the board.
WS2812’s etc. do not have a microcontroller in – it’s an asic containing simple logic
It contains a state machine with registers that handles PWM and input/output communications timing, quite a bit more than simple logic, more akin to what you could make with a CPLD than a uC though, true.
Isn’t a term “Neopixel” just Adafruit’s marketing name for WS2812 LED?
Yep.
Yes. “Neopixels” are the brand-name given to plain old cheap WS2812 LEDs. You’re an exorbitant fee if you’re buying “Neopixels” and they are no different than WS2812s or APA102s, etc. You’re overpaying whenever you buy anything from Adafruit.
nice led ..
$15..not expensive ..
The PIC they’re using 12F157X is ~$0.50. Add a very high estimate for such a small PCB of $0.20 combined with $1 for MOSFETs/passives (IRLML2060TR’s are <$0.25 on digikey) then $1 for the 3W RGB LED (more likely $~0.10). that's $15 / $2.7 = 550% markup.
I realize when "working with" a distributor to make a product they need to take a share of profit to cover inventory/staff/website/distribution etc.
But at these prices I could get PCBs made and assemble a tiny batch of 10 at home and still come out ahead.
I hope you start producing them soon. If you sell them at $4/led, that should be enough to cover your r/d and replacement costs, as well as cost for your employees’ salaries that put the boards together. Oh and since there’s a large number of people that have uses for these, whatever is left can be used to make a profit, you know, why businesses are in business. For profit.
I’d love to know where you’re getting 3W RGB LEDs for $1.
http://www.ebay.com/itm/261853467299
0.99$ per LED
Not hard to find at all: http://www.aliexpress.com/item/Free-Shipping-100PCS-LOT-1W-110-120LM-LED-Bulb-IC-SMD-Lamp-Light-Daylight-High-Power/1920526346.html?ws_ab_test=searchweb201556_2_79_78_77_91_80,searchweb201644_5,searchweb201560_9
They are open hardware, so I bet some factory in China is already making first few million units for the half or quarter if the quoted price.
Even the guys in China would do a better job of mechanical and thermal designs. e.g. using a flash light LED mount PCB.
5x markup is not atypical for a product sold through standard retail channels…
The price is a little high, but would not be considered as such if the PCB was designed as needed for product reliability. It’s very obvious from the pictures that it is not designed correctly, and even with thermal shutdown coded into the PIC, I would expect more death by heat/current than anything with these. A proper PCB would be designed with 2oz copper. Also, ignoring the fact that the holes are barely plated, you are expecting each module to handle passing 1Amp for every module after it. The comment in the write up about “only going full brightness for a couple seconds” is disappointing. “Here, use this awesome crazy bright RGB LED…….but please download the 20 page PDF of limitations and usages that void the warranty…….”
I have done several RGB LED projects involving 1.5 to 3 watt LEDs. The largest RGB LED project I was part of covered two sides and 3 floors of the Armani store on 5th Avenue in New York. We used tons of Osram Multi Ceromos RGB LEDs. For burn-in, the LED strips were ran at full brightness for 8 hours. Usually, a high powered LED will fail within the first couple hours or will last thousands of hours.
This is an excellent concept but this prototype was poorly executed. Would love to see this designed properly. In volume, the $15 price is attainable even with a proper design.
cant wait for china replicas, 15$ is a lot.
Instead of larger, brighter and more $$, I’d like to see smaller and less $, to the point where building a full VGA resolution display doesn’t require one to be a millionaire to avoid bankruptcy just buying the LEDs.
At the price they are asking, it had better be using a properly designed aluminum PCB that can be attached to external heatsink. What’s the point of buying a 3W one for that price if you can’t use it near the rated power because it uses cheap FR4 core and not designed properly?
Yeah I was wondering why they go with a aluminum PCB just to send all power components to the back.
The Aluboard will spread the heat, but isn’t sufficient for permanently using the pixel at 3W / white.
I’d prefer a slightly bigger board with all components on top…
The PCB on the OP is FR4, not Aluminum core. You can see the transparent material around the left screw hole.
Aluminum core can used as heat spreader. The only way to dissipate that amount of heat is to dump the heat from the package to an external heatsink. The copper on the FR4 isn’t going to be able to handle 5W (quoted in article) when it is on full blast. That’s a horrible design right there as he is wasting 2W for the constant current supply. There are chips that manages with lower drops on the sense resistors if you are going the linear path.
Also the PCB isn’t quite useful for tiling an array when the screw holes are on the 2 ears as that increases the gaps. Might want to look into diagonal mounting holes.
So at the end of the day, this is a poor amateurish design without a good understanding of thermal and mechanical planning and certainly not worth the $15 asking price.
For this money you can just get one of those 9 ws2812 boards available.
For $17 you can get 100x WS2812 LEDs. But sometimes it’s more practical to use one 3W LED than 10x 300mW LEDs.
There’s someone on tindie selling a 20W RGB flood light board (LED not included), with a discrete WS2811 controller. That seems even more ridiculously useless/cool.
It is better engineered:
– switch mode constant current driver to reduce heat/power consumption.
– This is a proper CC driver with inductor + diode(unlike a cheap PWM), so you don’t get flickers.
– LED array that is designed to be mounted, so you could actually get the full wattage with the properly sized external heat sink.
> WS2812s and Neopixels
NEOPIXELS ARE WS2812s!!!! Wtf is this disinformation campaign?? It’s a marketing campaign that everyone seems to go along with. Don’t buy “Neopixels”, they are overpriced and the same exact thing as WS2812 LEDs.
Hello,
i’m using some pixies but i like to reprogram the controller on the pcb of the pixie.
Is there somebody who has the original hex file, because when i build the .c file the led is dead. Or some tips how the build a working hex file (settings).
So i need the hex file to re the quite expensive pixie and start to cpr the pixie. And try again to delete the wdt function.