I am building LED Matrix's with Adafruit Neopixels, and I read somewhere that the amount of pixels you can control is limited to how much RAM you have on your controlling device, in this case, a "Raspberry Pi 1 Model B+". I know this is an older model, but I know it should be able to control some amount of LEDs.

Thanks for any help you might be able to give!

  • @jsotola Excuse me, how many can I control. I intend to use a separate power supply. – Aaron Mann Jan 14 at 16:51
  • The software require a block of memory for every pixel it controls. It's not a power issue. – fcm Jan 22 at 19:27

By looking at the serial protocol of the NeoPixels you should notice that each LED receives 3 bytes (24 bits) in order to set its color. This is the data that has to be sent out via GPIO in order to light the LEDs. Depending on your programming language and coding habbits you can calculate the required RAM.
In plain old C that would be #NeoPixels * 3 bytes. So if you have 10k NeoPixels that would akkumulate to 30kb of RAM. If you plan to get this high LED count, RAM is not going to be your problem but power distribution.

Maybe you are confusing the Raspberry Pi with a Microcontroller like the Arduino. There the RAM is a scarse resource. The 2 kb RAM is shared between the program and the array for the NeoPixel color values. The Raspberry Pi has 256 MB in its lowest incarnation (of which a big chunk is used by the OS - but you are still left with a double digit number of megabytes free).

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