Wouldn’t it be fun to add bright, beautiful NeoPixels to your Raspberry Pi project? However NeoPixels, and the WS2811/2812 LEDs that make them up, require a data signal with very specific timing to work correctly. Because the Raspberry Pi runs a multi-tasking Linux operating system it doesn’t have real-time control over its GPIO pins and can’t easily drive NeoPixels. Typically a small microcontroller like a Trinket or Teensy can be used to communicate with the Raspberry Pi and generate the NeoPixel data signal. However thanks to the excellent rpi_ws281x library created by Jeremy Garff, you can now control NeoPixels or WS2811/WS2812 LEDs directly from your Raspberry Pi!
Jeremy’s library solves the real-time control problem by using the PWM and DMA hardware on the Raspberry Pi’s processor. The PWM (pulse-width modulation) module can generate a signal with a specific duty cycle, for example to drive a servo or dim an LED. The DMA (direct memory access) module can transfer bytes of memory between parts of the processor without using the CPU. By using DMA to send a specific sequence of bytes to the PWM module, the NeoPixel data signal can be generated without being interrupted by the Raspberry Pi’s operating system.
As 2022 starts, let’s take some time to share our goals for CircuitPython in 2022. Just like past years (full summary 2019, 2020, and 2021), we’d like everyone in the CircuitPython community to contribute by posting their thoughts to some public place on the Internet. Here are a few ways to post: a video on YouTub, a post on the CircuitPython forum, a blog post on your site, a series of Tweets, a Gist on GitHub. We want to hear from you. When you post, please add #CircuitPython2022 and email firstname.lastname@example.org to let us know about your post so we can blog it up here.
Stop breadboarding and soldering – start making immediately! Adafruit’s Circuit Playground is jam-packed with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with the drag-and-drop MakeCode programming site, learn computer science using the CS Discoveries class on code.org, jump into CircuitPython to learn Python and hardware together, TinyGO, or even use the Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for CircuitPython, MakeCode, and Arduino. It has a powerful processor, 10 NeoPixels, mini speaker, InfraRed receive and transmit, two buttons, a switch, 14 alligator clip pads, and lots of sensors: capacitive touch, IR proximity, temperature, light, motion and sound. A whole wide world of electronics and coding is waiting for you, and it fits in the palm of your hand.
Have an amazing project to share? The Electronics Show and Tell is every Wednesday at 7pm ET! To join, head over to YouTube and check out the show’s live chat – we’ll post the link there.
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