I’m working with my first LED strip project - a sign I built for my wife’s new salon. I’m very happy with the results of my build but as I’ve been tinkering and testing around I realized if I go for all white (h=0 s=0 v=1) I get pure white from the first led and then as it makes its way towards the last I go to a yellow. Prehaps even more bizzare when I set the values to h=0 s=0 v=0 I get a greenish hue towards the end of the strip.
When the strip was whole this issue wasn’t present so I think my wiring may be the issue - I’m a beginner with soldering and this required cutting the strip into 4 pieces - I could well have overcooked something or created a small short. I tried my best to clear this by cleaning every connection but the issue persists.
I’m hoping someone knows the cause of this -or- perhaps even better a way for me to correct within code. I’m thinking there’s some kind of ‘drift’ in my hsv values and I’m wondering if I could throw a bit of code into the beginning of my patters to bring things back a bit.
What you are seeing is voltage drop over the strip. There’s some resistance in wire and strips, and when enough current runs through them some voltage is lost.
The color shifts because red LEDs have a lower working voltage than green and blue. So green and blue start dropping out or fading. The LEDs nearest power are still getting full voltage, while the ones at the end are much lower. This makes white turn orange, and purple fade to red.
For high current applications like this, you must “inject” power along the strip. Run much thicker wire from the power supply and join that with the power connections in the strip.
Calculate your power draw requirements and take a look at this chart to find an appropriate wire gauge.
The green use looks like a bad or stuck pixel. Maybe pixel count is off by a bit? Maybe one LED isn’t getting data.
@Spargo I agree with the wizard’s diagnosis: voltage drop.
I suggest you try this simple “injection”: in addition to connecting power and ground to the start of the LED strip, also connect power and ground to the end. Since your LED strip is in a circle, this will only require 2 short lengths of wire.
If this doesn’t work you’ll likely see the discoloration shift to the bottom of the circle. In which case you’ll need to also inject power (run power and ground wires from the power supply) to the middle of the strip (bottom of the circle).
Wow that makes me so happy to hear that is SO much easier than I was worried it would be ha ha ha! I’ll run some extra connections to the midpoint and end and see how that goes - thank you so much!