I was wondering if it’s possible to power the Plasma board + Neopixel strip with more than 3A (i.e., using a 45W USB-C port) directly through the Plasma’s USB-C connector.
Up to 3A is allowed (according to the USB-C specs), right?
I don’t know if the board can handle more than 3A.
Any suggestions?
You have two problems: USB-C has a max of 3A at 5V. So you wont find an USB-C power supply that delivers more. You cannot feed a higher voltage, the on-board regulator has a recommended maximum of 5.5V.
Now you don’t need an USB-C power supply to feed power to an USB-C plug, but without knowing the exact specs of the socket that Pimoroni uses, and without knowing the PCB layout and thermal dissipation it provides, a higher current might or might not destroy the board.
The main reason not to tinker here is that you can add multiple power supplies anywhere within the strip as long as you don’t connect the 5V of your power supplies together (do connect GND). The simplest solution would probably be to power the Plasma2350W with one supply and don’t connect the 5V screw-terminal of the to the strip.
I’m powering mine via J2, the +5V, data, clock and ground screw terminals. I have a 5V 4A supply wired to the +5V and Ground terminals. It powers my RGB Strip directly, and also powers the Plasma 2350.
[5V 4A (4000mA) switching power supply - UL Listed : ID 1466 : Adafruit Industries, Unique & fun DIY electronics and kits]
(5V 4A (4000mA) switching power supply - UL Listed : ID 1466 : Adafruit Industries, Unique & fun DIY electronics and kits)
I just cut the barrel jack off, then striped and tined the wires. Keep in mind that this will back feed +5V out of the USB C Jack. I use a data only cable when coding / programing. I cut the +5V wire in the USB cable.
Never thought of that, but it is actually a good and safe setup. The only thing is that you don’t have the Plasma “in line”, because power and LED connections are from the same side. Feeding directly through the USB-C as @pic is asking is certainly more elegant, but is limited.
BTW: Adafruit has a Neopixel BFF (Adafruit NeoPixel Driver BFF Add-On for QT Py and Xiao) that makes for a very small package. I tried it but also here the arrangement of the cables is nothing I would like to have in my living room.
Thank you so much, I now have a clear idea of my project.
I have 114 LEDs, but they will never all light up at once, so I’ll opt for the simplest solution. I’ll directly connect a 3A USB-C power supply (e.g., https://www.raspberrypi.com/products/type-c-power-supply/) to the Plasma board’s USB-C port and limit the number of simultaneously lit LEDs (N) via software.
I’d need a little help calculating N correctly. I’m assuming, in a worst-case scenario:
If I needed more than 3A, I’d opt for one of the solutions you suggested.
Thanks again,
Pino
I did some measurements. I usually set the brightness to 10% (0.1), and even then you need sunglasses if you set all LEDs to pure white (255,255,255). At 10%, I have something like 4.5-6mA per pixel. If you stay away from pure white, you are far below. Now this is for some animations I made with a 8x8 matrix (i.e. 64 pixels) or with a 60-pixel ring. If you have a strip and want to use it for some background lighting, you might need a higher brightness.
The board itself wont exceed about 60mA. During WLAN activity, it will have very short spikes above 180mA, but the board will never be the driver of your current needs.
I’m running a 144 pixels per meter strip as desktop lighting.
Flexible RGB LED Strip (aka NeoPixel, WS2812, SK6812)
When illuminated they are “all” illuminated. The intensity varies, but it’s not very often I go full bright all white. I use an Encoder Wheel to set the color / pattern, and adjust the brightness on the fly.
My one big safety related gotcha, is the back feeding +5V to what ever device I’m programing it with. Without isolation bad things can happen when two regulated power supplies fight each other trying to regulate the Bus. I just leave my custom programing USB C cable plugged in and tucked out of the way. It’s yellow with some black electrical tape in the middle. As soon as I see it I’m reminded of what its there for. ;)
I have patterns programed but to be honest, I only use those for showing off. More often than not I’m running White or Red at maybe 25% of full brightness. I have it on now, it’s about 5:30 AM and the only light in the room other than my RGB Strip is from my three monitors. Black keyboard with white text. It makes a big difference, for me anyway, as far as eye strain and headaches go. ;)