Hi all, need some advice with an issue on my first project.
I bought a WS2815 5 meter 12v 60 led per meter (90w) strip, a ESP32, a 12-5v converter and large 480w 12v PSU. I connect the power supply to the 12-5v converter and the led’s and the converter to the ESP32.
I though I would get a large PSU so I could power a number of strips off it but dont know if this is causing the issues im seeing.
Anyway everything works from a WLED perspective, can connect, change colour, programs etc. but the LED seems to be fairly dim, and sometimes the whole strip flashes white. If i reduce the pixel count in WLED to say 30 the leds are much brighter but still ficker white when changing colurs. Any suggestions?
Hi @tonyno, thanks for the reply. Im struggling to understand your suggestion. The power supply has a voltage adjustment. Could you elaborate on the suggestion?
So i though i’d try plugging in the esp32 via usb and get very bright constanlty changing colours while in the solid colour mode on WLED. the esp32’s blue light keeps flashing every second which corrisponds with the change in colours on the LED strip. No idea what is going on.
With a 5m strip containing 300 led’s you will need a minimum of 2 power injection points, one at each end of the strip to help solve the brightness issue. Flickering will almost always be down to low signal / voltage on the data line creating errors.
Take a look on this forum as there are many posts relating to this problem. Most are quickly corrected with a simple add on component (Line level shifter) that costs next to nothing. Below you will find some simple wiring diagrams of how they connect to your led’s.
Note Voltage will need to be adjusted to feed your 12v pixels as these circuits relate to the WS2812b pixels
@Modelman Thanks for this. From what i understand, there is a 3.3v out of the esp32 (D2 in my case) which i need to increase to 5v to address the “low signal / voltage on the data line creating errors”
I think i have found something on ebay for a small cost. Do I need the 470ohm resistor as well?
Just for fun I recently tested a 470 ohm resistor using the SN74CT125 level shifter on a 10m (33ft) data run and it worked perfectly. Basically any resister between 100-470 ohm will work with a level shifter. It’s simply acting as a buffer protecting your first pixel from peaks and surges.
The advantage of the SN74CT125 is that you have 4 independent level shifters in one package. Great if you ever want to use multiple pixel runs with long data lines.
What I get now is the first ~50 lights are lit but i cant seem to control anything. bypassing the shifter and resistor makes it work with the given issues i have been having above. Im now starting to think the shifter i got may not be right. Any thoughts?
There are some shifters than cannot handle the response time needed to control pixels.
The most popular are the 74HCT125N, SN74HCT125N, 74HCT125 variants which come in a 14 pin package seen below. These just seem to work great with everything I’ve ever tested.
After folowing your advice I managed to get some ‘SN74HCT125N’ chips and all is working perfectly. I guess it was all there in varisous doumentation but I thank you for helping me through it. Now on to working out the best way to mass produce this setup
Perhaps some people have already done it. A few WLED users have developed custom PCB designs to help power and control digital addressable LED strips.
I personally like Quindor’s QuinLED DigUno - which can now control multiple strips, and the QuinLED DigQuad which has fantastic capabilities to safely control 4 strips with a single ESP32.
