While these aren't RGB pixels, the process is the same for any panelized design I create, including the layout for the WS2801 + SMD RGB pixel in this thread. I needed to make 630 bright green LED pixels and rather than buying the LilyPad pieces (https://www.sparkfun.com/products/10046) which would've cost me upwards of $500, I decided to make my own. On a 50mmx50mm piece I can cram 23 of them: a grid of 7x3 plus two extra to fill the rest of the board.
Production of boards was $30 + $5 shipping. LEDs and resistors just over $200. My time: priceless.
Here's me cutting a single board into pieces, takes me a little over 2 minutes each (I already trimmed off the extra two that are along the top edge of each board). I should point out that these are 0.8mm FR4 boards, however the WS2801 pixels I created above were done on 2mm FR4 boards. Cutting is just a bit slower for those.
Sorry for the delayed reply, I just moved to my first (owned) home so I've been slammed the past few weeks. That's an awesome video! I have a dremmel on my wish list, but I think that sort of cutting may be out of my level until I get some better gear (and experience). I could probably order a board pre cut tho.
You had mentioned bending the LED's using the module you have.
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Like I said, you could just take a regular 3mm through hole LED, bend the bottom 3-5mm of the legs at a 90 degree angle and solder that to the boards I created.
Do you still have a few spare of these available? If I could use this technique to piece together a small 4 or 5 string light, I'd have the confidence to order all the rest of the parts I'll need. (part of my problem is I want my boss to pay for the bulk order once I know for sure what I'm doing, this is a team morale project:p) I would certainly be willing to pay for the parts, I just don't need the whole gambit.
Now for some even more basic questions. How did you go about creating those boards? I've heard (and seen you guys) talk about Eagle. Do you just load up the sketch in eagle and then have someone fabricate the parts? How expensive is that normally? I assume to get them down to $1 a piece, it would have to be pretty cheap or did you get some bulk discount?
You mentioned putting the LED behind the map, were you thinking of the light shining through the paper or something else? Super dumb question, but I shouldnt have any problems with conductivity when plugging a LED through the paper and then posterboard before connecting to the chip should I?
You really want to keep the LED close to the IC. Running long wires between them can lead to issues. You could use regular through hole LEDs with this if you change the layout to allow for the legs to go through, or you can bend the legs and solder them as if they're SMD parts, just on the surface of the board instead of through it.
On the other hand, having SMD lights like I did means you can put the LED behind the map without needing to poke a hole. Might be nicer ...
I see. Thanks for setting me straight on the LEDs being wired at a distance vs closer to the actual chip. My first vision of this project involved lots of TCL5940 but I would still end up running the LEDs 2-5 feet away from the chip.
You mention being able to put the LED behind the map. Do you mean put it behind the map and have the light shine through? I hadnt thought of that, but it could potentially work, however I do have like 12 pins to put in florida so even on a 5 foot map I need a bit more standout per pixel.
Something like this http://www.ebay.com/itm/370729430086, (in a ws2801 version) may work for me, I could run the LED through the paper, stick it into the chip on the backside of the board, and then connect each chip together. Seems kinda clunky tho, maybe I'll have to cut the hole in the map :/
Awesome information so far in this thread! I feel like I'm starting to have a better understanding of what I'll need to do, but since we're mostly talking about SMD I still have some gaps.
In order to have my "loose" pixels, I'd need to have all of these parts wedged into a small area. I could put the chips on a breadboard though, with the resistors and capacitor and just plug each long LED wire into the breadboard :/
Or I guess I could build something like you've shown here but instead of connecting the LEDs directly to the chip, I'd run them via a wire for each leg of the LED. I only need about 50 RGB LEDs so four or five of these should do the trick.
Sorry to ramble on, hoping my random thoughts will inspire someone to set me straight :p I'm pretty new at this so I apologize if my questions aren't up to par :p
So I have this map project that I'm working on and I bought a prebuilt string of ws2801 LEDs. So far the project is going great and I'll be done with the prototype shortly, but in an effort to build a more svelte end result, I'd like to look into building my own string. To explain, the prebuilt strings come with bulky cases, I need something that I can stick through my map, and do the wiring on the back side of the board(prob posterboard). This will allow me to place more LEDs in a small area and damages less of the map for removal (no big hole, just the LED legs). I'm thinking the legs will come through, I'll solder them to some wire and run it over to a breadboard with the chip attached and linking back out to the next led.
For those who end up here for info some day, yes, if you want an easy way to control a ws2801 string download the adafruit library, https://github.com/adafruit/Adafruit-WS2801-Library/blob/master/examples/strandtest/strandtest.pde run the example and easily pick up on how to control each individual LED. This allows you to still use the standard ethernet shield for control.
Use the following to light up the pixel of your choice
I've gotten some great info from this topic, (and others) so I hope its okay that I necroposted. I'm starting down this path myself. Following all the great tips I can control my LEDS individually (mostly) using fastspi, but in seeing the last few posts I know I'm running up against my next obstacle soon
That is because the ethernet add-on that you're using is more than likely also using the SPI bus.
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For my own project last year, I went the bit-bang route. I only had two strings of 20 LEDs each. I used the analog pins (of all things) to control the strings, A0 and A1 for one, and A2 and A3 for the other. Note: bit banging IS slower than SPI, so depending on how fast you plan on sending data to the LEDs, bit-banging them may not work for you. For me it was plenty fast still.
Could you go into a bit more detail about bitbanging these pixels? Like most people, I'd like to write a function that will do most of the lifting and let me do changeLED(LED[1],'blue'); Since I'll be using the standard Ethernet shield on 13, I'll need a way to go without fastSPI. I'm hoping my project will accept http requests to turn a pixel a certain color, and then another digital out to set of an alarm (when a project needs attention) So I dont think it needs to be fast, the colors wont change rapidly and will stay solid lit.
Just set everything to white first (you don't need an array for that), then cycle through the BlueLEDgroup array and turn those blue. When you're done with that, then you can call FastSPI_LED.show() which will turn the LEDs on.
Even though I'll be moving off fastspi after your advice, I'm curious what the single command is to set the whole string white
OTOH I noticed that near the bottom of the front page it says:
Note for people using sparkfun's ws2801 led strips - you need to call FastSPI_LED.setDataRate(1) before calling init/start. The library defaults to a data rate of 0 for ws2801 strips, which is valid for the chips on the 12v strips, but not on the 5v strips (or, at least, the 12v strips that I have here) - it's too fast and you get weird random flashing occuring.
They are dancing mad now! I should have known to include FastSPI_LED.setDataRate(1), I saw that in one of KirAsh4's other posts but didn't think to add it.
Thanks a ton for the help, my next steps are going to be to learn to control each one individually then hook up the ethernet to start addressing them from there I'm sure I'll have lots of questions along the way so I'll keep you informed of the progress.
I updated the sketch to reflect pin 11 and moved the green wire over to it. I'm still getting rather eratic output from the lights. See below Sorry for the low quality, was trying to rush this in during lunch. There are 25 lights in the strand, only the first few are lighting up in this example, but in various testing I have seen the whole string power on.
I've connected it up based on this spec, but all I really get is the first LED lit up blue. This is green to 13 and yellow to 4, to match the code.
If I switch Yellow and green, I get various lights lit up but it does not follow the pattern designated in the code. I get eratic flashing. If i remove the data from out 4, I still have various lights lit up. I've included a few shots to help debug whether maybe the lines are done wrong.
As for the code, I'm using Pin 4 as specified in FastSPI example. I commented out the other modes and just ran FastSPI_LED.setChipset(CFastSPI_LED::SPI_WS2801);. I'm hooking clock into pin 13 and digital into 4.
Input Output My connection Do these solders look okay?
Hmm. This map will have about 50 LED to be exact and I plan to keep them at a solid color to indicate account status. Ideally I could leave this plugged in forever, but if I need to switch out off I can. You said I need 5-6 Amps, does that mean the v5 won't do it?
Power supply volts is usually independent of amps. The 5 volts aren't negotiable, the amps are.
I'd get at least 6A if you're going to leave it on 24/7. 8A would be even better.
hm, I'll probably come back to you on this one. I should be able to drive this from my PC until I know enough to try and attach an external supply. Thanks for the recommendation!
Tonight, i'll cut of the SM connector, hook it to Arduino and let FastSPI fly. thanks again
Note that strings like this can require a surprising amount of current. If you switch all LEDs on simultaneously that's 60*3*0.02 = 3.6 Amps. You need at least a 4 Amp power supply, preferably 6 Amps or more if you plan to switch it on for hours at a time (although you probably won't have it all white very often in practice so 5-6 Amps is probably OK).
Hmm. This map will have about 50 LED to be exact and I plan to keep them at a solid color to indicate account status. Ideally I could leave this plugged in forever, but if I need to switch out off I can. You said I need 5-6 Amps, does that mean the v5 won't do it?
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