# LED lighting project wiring Questions

let me begin by thanking anyone and everyone for any help.

I have a serious lighting project and am likely getting very ambitious.

I am trying to wire up a series of WS2812 LED strips. Each 2 strips of 24 LEDs will be contained in a box, so 48 RGB LEDs per box (think 2 rows per box). I will ultimately have ~48 boxes, so over 2300 LEDs. I want to wire these as simply as possible. There is a Power, Ground, and Data. Data is directional. I figure to avoid voltage drops I have to bring power in every third box or so. I am told each LED pulls 20 mAmps and there are 3 LEDs per WS2812 (R,G,& B). So in reality each of the 48 LEDs is really 3x, which equals 144 per box. Thus 60mAmps per RGB LED or 2880 mAmps per box, if my math is correct. Oh, and these are the 5V variety of LEDs.

Here are my questions:

1. What gauge wire could I use? Would quality Phone line or Cat 5/6 work if I get a 22 gauge version?

2. Could I use those connectors? Phone/Cat5/6 or are we talking too much power?

3. Could I daisy chain the data or would this cause problems? Do I need to run data out to a junction box?

4. Is there any easy way to connect or bring things back to power the the brain running all these lights? Was thinking of a Teensy 3.1 to control everything.

Any advise would be appreciated. This will be for public displays and I want to keep EVERYONE, me included, safe around these lights.

update:

Was planning on implementing in stages. Have 30 m of the LED strips at the moment and that will let me make ~25 of the boxes. Yes I know that is still a lot, but can wire up a couple of them at a time and test everything. This is why I am wanting to dot the i and cross the t.

If I read the amperage table correctly 22 gauge wire would support 7 amps. So I still have almost double the capacity. Thanks for the catch on the controller.

Any idea on those connectors?

update:

At the moment I have a 60Amp power supply. Could get more of these or something larger. Haven't figured that out yet.

• First, you have ignored the controller current, which is an extra ~20 mA, so it's about 3.8 amps per box. Have you considered your total power requirement? 185 amps is not what I'd recommend for a first project. And at 5 volts, that's a 900 watt+ power supply. Jul 6 '15 at 23:16
• What is the source of power for your circuitry? Jul 7 '15 at 14:24
• I assume you are using something like powerstream.com/Wire_Size.htm to get 7 amps. You should pay close attention to the next column - power transmission, which better describes your application. As for current, see 52ebad10ee97eea25d5e-d7d40819259e7d3022d9ad53e3694148.r84.cf3.r… for a typical RJ45 connector. 1.5 amps max. Jul 7 '15 at 19:58
• The best wiring solution will depend on the the physical layout of the boxes and the proximity of power sources. Are they going to run end-to-end in a very long line with power sources available only at the head and tail, or are they going to be in a grid? Jul 8 '15 at 4:11
• It this a temporary installation, or something that needs to work reliably for years? Jul 8 '15 at 4:17

People typically use JST-3 connectors to connect these strips because that is typically how they come from the factory. You can get more of these connectors from AdaFruit or Amazon or lots of other places.

If you are going to be soldering a lot of these connectors on, then I recommend getting a solder pot. You can then dip the tips of the wires into the pot, then the end of the strip into the pot, and then just hold the tip of each wire to its pad on the strip and touch with a soldering iron for a second. It goes quick.

I'd try to organize your cable runs so that maybe you hit a whole row of boxes horizontally with each logical string. This is really just about physically making the cable easy to deal with, so do it however works best.

For power, I personally would run a bus of of ~14 gauge black/red wire along with each physical string of strips. This cable should be able to support at least 1500 pixels if connected to a suitable power supply. About once every 100 pixels or so, I'd tie the power lines of the strips into the power bus using tap connectors. If you want to whole thing to be completely disassemblable, you could use Molex power connects between the boxes (or groups of boxes), just make sure the connectors can handle the full amperage you will be pushing though them.

I'd prefer to run each physical string into its own power supply rather than having one big one, again just to keep things physically manageable and to be able to use smaller supplies and keep your wires cooler. :) I've had very good luck with the Meanwell 5V DC supplies, but you can get very cheap supplies on amazon and alibaba.

For driving the data to the whole display, you could use something like an arduino but most of the code out there can only drive a single string so you'd have to daisy chain all of your strips into one long logical string. Yuo will also have to jump though hoops to drive that many pixels with an arduino's tiny amount of RAM unless your patterns are very simple. I'd probably use a beaglebone black running this fork of the popular ledScape code...

https://github.com/Yona-Appletree/LEDscape

This can drive up to 48 strings simultaneously and has lots of convenient ways get you pixels into it, including being able to use Processing for very fancy stuff.

If the data cables from the last string end up very close to the beagle bone, you can connect them directly to the bone's IO pins. Even though the bone is sending 3.3 volts and the neopixels want at least 3.8 volts, I've found that it almost always works fine. If the run between the bone and the farthest string is going to be more than a foot or two or you see glitching on the display, then you can make a very simple level converter from a couple of transistors and a resistor or you can buy nice (but expensive) ones here..

http://rgb-123.com/shop/

Note that they also sell the PixelPusher which should work for you, but is also a little expensive for my tastes.

Note that when you are connecting everything up, try really hard to always get the pixels powered up before sending a data signal into them otherwise you can blow the 1st pixel in the string.

Report back with your results!

UPDATE: Here are some photos of 1500 pixel panels I build using some of these techniques...

https://www.flickr.com/photos/bigjosh/sets/72157655896681772/with/19099344714/

Note that using a Beagle Bone also lets you use a Wifi to control the display from your cellphone!

• Awesome, so much good info in here and answer many of my questions. Thank you!!! Will keep you posted, that Soldering pot looks awesome. I have been dreading that portion. Thanks! I am sure I will have questions, must digest it a bit. Jul 16 '15 at 17:57
• @bigjosh I personally would run a bus of of ~14 gauge black/red wire along with each physical string of strips. This cable should be able to support at least 1500 pixels if connected to a suitable power supply. 1500 px * 60 mA/px = 90 amps. Ampacity for 14 gauge wire = way below that. Can you explain? Aug 6 '17 at 19:49
• I'd use a separate power supply & cable for each string, and keep the strings less than about 100 pixels each. You can go higher, but eventually the current gets hard to manage and power supplies get expensive and dangerous and wires get hot. Aug 7 '17 at 6:59

I have been cutting the strips to get them to fit inside the box that I am using. The boxes are mobile, but the LEDs will be permanently installed inside and used in many locations.

As for details on the LEDs, here is where I got them: aliexpress.com/snapshot/6335436125.html?orderId=64519262042016

This is my current power supply: aliexpress.com/snapshot/6335436120.html?orderId=64519262052016

I will likely have to bring power in at multiple locations, which is why I want an easy connector to create junctions

The boxes I am referring to are these: flic.kr/p/toW8id