Tesseract
Posts: 1
Joined: Sun Aug 07, 2016 12:39 pm

Control 5m of WS2812 LED Strip: Wire it up

Sun Aug 07, 2016 1:20 pm

Hi everyone,

I want to control 5m of WS2812 LED Strip with my Raspberry Pi, which will be placed around two ikea billy shelfs. I read some articles and tutorials regarding this topic:
- http://popoklopsi.github.io/RaspberryPi ... /#!/ws2812
- https://learn.adafruit.com/adafruit-neo ... onnections
- http://powerpi.de/atemberaubendes-ambil ... al-teil-1/

I understood that I need a maximum of 9A for 150 LEDS, because one LED consumes a maximum of 60mA. In the first link above, the current runs through the breadboard, which seems to be a bad idea when using 9A. In the third link the LED strip is powered directly using a separate power supply. Only ground and data is connected to Raspberry Pi (and clock, because he uses a WS2801 strip).
Furthermore it seems to be good practice to connect a capacitor between the led strip and the power in order to smooth the initial onrush of current and a resistor between the DIN and the GPIO in order to prevent spikes on the data line. Also I need a level shifter, because the outgoing data signal of the RPI is 3.3V and the LED Strip expects 5V. Interestingly, the guy in the third tutorial doesn't use a level shifter, but maybe this is because he uses a WS2801 strip, I don't know.

Up to now I end up with this:
I have a 5V 10A power supply (https://www.amazon.de/Schaltnetzteil-LE ... rds=5V+10A) which separately powers the LED strip + a capacitor. The led strip has to be connected with a ground pin (e.g. pin 6) and GPIO18 (pin 12) for data + a resistor.
The problem is, I don't really know how to put this together with the level shifter on the breadboard.
Is there anything what I need on top of the already mentioned stuff.

Would be really nice, if someone could tell me how to wire this up. :)
I have no problems regarding the software side, but I'm really new to this hardware stuff...

Thanks in advance :D

User avatar
Bottersnike
Posts: 52
Joined: Wed Apr 06, 2016 7:17 am
Contact: Website

Re: Control 5m of WS2812 LED Strip: Wire it up

Fri Aug 19, 2016 7:30 am

I had a similar problem a while back. What I ended up doing was having three transistors coming out of my pi's GPIO which connected onto R, G, and B and I then connected the GND of my power supply to the GND pin on the strip. The transistors use the GPIO to switch the 9v going through them and into the pi.
Micro:Pi is an (almost) fully fledged IDE for programming a BBC Micro:Bit using C++. Go check it out at https://bottersnike.github.io/Micro-Pi

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