I am using an 8x8 64 LED WS2812 Matrix panel connected to a wemos d1 Mini. It is battery operated with the Wemos powered from a 3.3v voltage regulator and the LED panel powered straight from the battery. Intermittently the panel goes all white and pretty bright instead of displaying the image I sent over. Normally, once it goes all white it does not show any more images until I reboot everything. I have the resistor and capacitor in place as adafruit recommends in the neopixel uberguide. I don't know of a way to debug what signal is being sent but am curious if anyone has ideas why the panel would go all white. Is it not receiving a signal? Is it receiving bad signal? Is it some default state?
A bad signal is a possibility, yes.
In theory, ws2812 needs a 5V data signal, but the Wemos is a 3.3V device, so can only put out a 3.3V signal. Generally, this is enough, but it is not guaranteed to work. You could try using a level shifter to boost the 3.3V signal up to 5V. But do not use one of those eBay 4-channel level shifter modules designed for use with i2c devices, they are not fast enough for use with ws2812 leds. A better choice is a 74hc14 or 74hct14 chip.
But before trying a level shifter, post a schematic showing how everything is connected and powered. You mentioned a 3.3V regulator and I wonder why you would use that because the Wemos has one built-in. So I am also wondering what this regulator is and how you connected it to the Wemos. Maybe you connected it in the wrong way and this is the reason for the problems.
Use a 74ACT part, can see 2V as a valid high signal.
72ACT241 for example
https://www.digikey.com/en/products/detail/texas-instruments/CD74ACT241E/1692008
Power from 5V, with 0.1uF cap from Vcc pin to Gnd.
I have attached the schematic. As I am driving this with 4 AA batteries which starts at 6 - 6.4V I thought I needed to use a voltage regulator. I have done some tests and the 3.3v can work but I may be finding out it does not always work.
LEdbuttonSchematic.pdf (103 KB)
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