I'm mainly trying to follow this guide here in order to connect some LEDs to a Raspberry Pi. I've read other guides as well, but this link is where I got the majority of my setup done. I've never used a Pi, have never worked with LEDs, and have never played around with electronics parts before – so I'm going into this mostly blind. Any help would be appreciated.

I do have some programming experience; and it looks like there's no problem with the software – I've gone all the way to the end of the tutorial with no error message. Regardless, I still can't get my LEDs to turn on or do anything (technically not quite true, as I managed to get the very first LED to turn green once, but I'm still not sure how that happened).

- First part of the setup: a Raspberry Pi Zero W is powered (switch on the right is flipped on) and connected using a breakout kit to a breadboard with a 1.44" LCD screen in the middle. The breadboard is also connected to the LEDs off picture.

- A closer look of the Pi. The Pi works. I don't think it's the source of the problem. I had some trouble with the GPIO pins, but I figure they must be working fine if the screen turns on – maybe this is a wrong assumption?

- A closer look of the LCD screen. It turns on. I've also turned SPI on in raspi-config. It seems to work, although I haven't tried to get it to display anything. Is it possible that this screen being in the middle is interfering with signals getting to the LEDs? Doesn't seem likely, but maybe.

- The breadboard and LED setup. The LED's 2 separate red and white wires are connected to an adapter and is powered with 5V, 3A – in the future, I don't plan on having more than a few LEDs turn on at a time, so 3A seems sufficient. Two of the LED's 3 conjoined red, white, and green wires are connected to the breadboard: green is connected to GPIO 18 (6th from top on the right), white is connected to GND (5th from top on the left), and red is not connected to anything.

I've also tried white going into GND (3rd from top on the right), nothing changed (which was expected). I've also tried having all 3 wires connected (where red was connected to 1st from top on the right); when I did this, the power connection to the Pi became redundant (i.e., switch on the right in picture #1 was turned off, but both screen and Pi turned on anyway). Is it possible that in the latter scenario, I may have shorted something in the circuit and destroyed it?

- The LEDs. Nothing special here. This end is not connected to anything.

I go through the tutorial and run strandtest.py. The software runs fine, but the LEDs are unresponsive. So what could I be missing?

  • 2
    Can't tell from your setup image, have you got a common ground between LEDs, Pi and LED Power supply? Check your cheap T Cobbler board doesn't have any bridged solder between pins - mine had 3 short circuits.
    – CoderMike
    Jan 30, 2020 at 18:38
  • 1
    Yes, I believe the ground (white wire) is correctly connected. Good idea with the soldered pins, I hadn't thought to check them, but this one's clean. Jan 30, 2020 at 18:53
  • 1
    Randomly changing connections is never a good idea!! A hint to troubleshoot: instead of controlling the leds with a gpio just use the pi‘s 3.3V pin and manually connect it to the led‘s control pin (after you found out the correct pinout of course)
    – Sim Son
    Jan 30, 2020 at 20:37

1 Answer 1


If anyone is running into the same problem and is reading this post: I ended up fixing it and it's working just fine now. All I had to do was change the brightness down on the LEDs. I did some math (which, to be fair, I really should have done from the start) and apparently the strip was drawing more power than I estimated in the beginning. Bringing the brightness down also has the added benefit of making it easier to look at too.

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