WS2812 LED strip cable connectors - Page 1
Forum section: electronics / beginners

author: HerbCSO
author_rank: Newbie
timestamp: June 27, 2020, 12:20:15 pm
content: Hi there, electronics n00b here.I'm working on an WS2812 LED strip under-cabinet lighting project. I'm planning to drive the LEDs with a Raspberry Pi ZeroW, and they're the 1m, 144 LEDs/m variety. I'm basically following the Adafruit Neopixels on Raspberry Pi tutorial for connecting it all up (https://learn.adafruit.com/neopixels-on-raspberry-pi/raspberry-pi-wiring), and I'm using the 74AHCT125 level shifter for the control logic. I have power hooked up through a separate connection to a 5V, 200W power supply to drive 3 strips, connected in series. I'm feeding in power from both ends since feeding it in from only one end causes a pretty significant dip in voltage and therefore brightness at the end of the strip. I've had it all hooked up for testing the circuit and everything seems to work fine. Draws about 89W with all LEDs at full brightness all white (RGB all on) and I can control all the LEDs perfectly well with some of the sample Python scripts. (I'm happy to take input here if folks think any of this is a bad idea.)I also got a black LED channel system to mount the strips under the cabinets and keep everything looking nice and neat (https://www.amazon.com/gp/product/B07KC8P2KD). I'm planning to mount the strips in 3 separate 1m sections, one under each cabinet, so I will need cables to connect them.Now my question:I'd like to be able to individually connect and disconnect each strip, so I need some connectors. Can anybody recommend specific ones (for shipping to the US)? They would need at least 5 pins - VCC and GND, the data line, and another VCC and GND for hooking up to the far end of the strip. I'd love to use something like a USB-C plug form factor, but I don't know if I can just get a USB-C extension cable like this one (https://www.amazon.com/dp/B083YT24VS), cut it apart, and start soldering wires. Aside from the fact that the wires are likely tiny, since there are something like 20 separate connections AFAIK, I suspect the electronics in the plug would just plain not work if I hook them up "wrong" (it'd be wrong any which way I do it since this wouldn't be USB anymore by any stretch of the imagination ;] ). Also I frankly don't think my soldering ability is good enough for that many teensy wires.I've been scouring AliExpress, Amazon, and eBay for connectors that might work, but haven't been able to find anything I like yet. They're either big and clunky (like this onehttps://www.aliexpress.com/item/32812653428.html), which is not great since they'll be visible under the cabinets, so I need something that looks nice, or they're too tiny to be able to handle the load (e.g. the 5-pin variety ofhttps://www.aliexpress.com/item/32920898043.htmlwhich I suspect is an under-sized AWG 20 cable orhttps://www.aliexpress.com/item/32836886896.htmlwhich seems to be an AWG 22, and I think I need at least AWG 18 for the full power delivery).Am I just stuck with the big and clunky so I have to find a way to hide it?

author: ozcar
author_rank: Frequent Contributor
timestamp: June 27, 2020, 10:15:54 pm
content: 144 LEDs per metre sounds high to me for under-cabinet lighting.Your power usage is a bit lower than I would have expected though. More often than not I see 20mA per colour per LED given as the maximum draw, so 60mA per LED for RGB ones. You'd think the seller would know, and they do say 30W total, which works out as about 42mA per LED. However, I note one reviewer there says that information on the bag indicated 43.2W, which as it happens is exactly what you get if you take the current to be 60mA per LED.Either way, the power connectors have to handle around 20A+. I'm thinking maybe keep the data line separate, and use Deans plugs as used in the R/C world for the power. Not sure why you have to have the connectors where they would be visible?

author: HerbCSO
author_rank: Newbie
timestamp: June 28, 2020, 06:04:10 pm
content: Thanks for the tip about the Dans plugs - I'll look into that. I have some separators between the cabinets, so I need to run a connector through that. It's not really visible unless you're kid-sized, but I'm trying to be a bit of a neat freak about this install. So the cleaner of a look I can get the better.Data line is pretty much separate - these strips come with an extra set of power cables. They do also get pretty warm when running full blast, so I'll likely cap them to 50% max brightness when running full white.I got the 144/m because I also want to do some lighting effects with them (much to my wife's chagrin... ;] ).As for the power usage: I totally agree. I'd read that they were supposed to be 60mA per LED, so not quite sure why it's lower, but the measurements say that's what it is.