Frank Hunleth presented a great introduction to Nerves at the March 25th meeting of DC Elixir.

He began by showing us some commercial products controlled by Nerves. They contained custom circuit boards that included a capable processor running Nerves and Elixir code from onboard flash memory.

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Frank explained how Nerves supports embedded systems by bundling a Linux kernel and drivers with an Erlang BEAM, Erlang libraries, Elixir libraries, and an Elixir application. The firmware image can also include data files and Linux binaries.

Frank demonstrated the Lumos library he is developing to control NeoPixels. He connected a strip of RGB NeoPixels to the SPI output of a Raspberry Pi 5 computer running Nerves. Meeting attendees connected to IEx or LiveBook running on the Raspberry PI via WiFi. After Frank revealed the function call needed to set the red, green, and blue levels of a particular NeoPixel, attendees began experimenting. We became wizards in training.

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Discussions continued after the meeting at a nearby Dog Haus Biergarten.

It’s not. I had intentions of adding animations, polishing the docs, and making it public. The SPI method of driving WS2812 strips works really well.

However, I rediscovered GitHub - a-maze-d/fledex: Small library to help program an LED strip · GitHub right after the presentation. It uses the same technique for driving the LEDs that I did, and it has so much more support for animations and color correction.

My current plan is to switch to fledex. I think it supports everything I need and more.