Thread by @BrooklinJMyers

Todays summary: Watched @lawik's LiveStream: Video: Nerves, Livebook & small displays (eInk, OLED)
underjord.io/livestream-ner…

How @NervesProject helps you get started with Elixir and IoT without needing to know a lot about the hardware.

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#myelixirstatus #elixirnewbie

Raspberry pi is a great way to get your start in IoT, and Nerves and Livebook take that even further. Cool enough: the first real Elixir code Lars wrote was for the Rasberry Pi Zero.

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You can sandwich a Rasberry Pi and an eInk display together. The Rasberry Pi runs your application and your application can use The Libraries Inky and Chisel to write to the display.

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To do it yourself, you can clone nerves_livebook and follow the getting started guide with additional steps in the "going further" section to handle nerves_livebook not working (yet) with mix install. You need to add Inky and Chisel dependencies and a font for Chisel.

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The Inky library allows you to write to the display using the Inky.start_link function with an InkySample and then set up a painter function to redraw the entirety of the school.

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The Chisel Library made by @lgr0ldan allows you to convert a bitmap into pixels which you can then drop onto an OLED display. Chisel takes in a put_pixel function which draws one pixel at a time, deferring the full render push until every pixel is ready.

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the mix firmware with a MIX_TARGET=<yourdevice> command in Nerves Livebook pushes a firmware update to your app by making a second partition to boot from and keeps the old partition in case of a serious issue.

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The Raspberry Pi Zero is great for having fun with IoT. For more serious projects Lars likes the Pi 3 and Pi 4.

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Lars also shows how to connect a game controller peripheral with an analog stick and a couple buttons to the Rasberry Pi.

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You can read the button states using the Circuits GPIO library. GPIO (General Purpose Input Output) is a common way of working with simple electronic devices.

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You configure the GPIO pin numbers for your hardware, and then you can read the state using the Circuits.GPIO.read(ref) function.

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You can use set interrupts to respond to changes in the game controller's state. First, you create a Genserver, which listens to any incoming set interrupt messages.

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Then upon receiving a new set interrupt message with the current controller state, you respond however you'd like - for example, you could draw to the screen. Taking that further, you could make a game!

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Really enjoyed this stream by Lars. I wasn't able to catch it live but hope to catch the next one.

For the full video go here: underjord.io/livestream-ner…

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