What is Nerves?

A set Elixir libraries for embedded hardware development.

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What is Nerves?

This Talk

Explore workflows for Nerves in various contexts.

Develop, debug, and deploy firmware to Nerves targets.

Nerves #FTW

  • Developer experience (DX)
  • Documentation
  • Open source community
  • Nerves Core Team
  • Hardware support

Now is the best time to get started with Nerves.

"What about the chip shortage? Why now?"

Reasons

Workflows:

  • Host
  • SD Card
  • Serial Cable
  • HDMI Cable
  • USB Cable

 

  • WiFi
  • IEx
  • Hotswap
  • OTP
  • Livebook
  • NervesHub

What's in store?

Host

Host

What/how?

Code written on and for the host environment.

 

 

It works, ship it!

Keep application and hardware code separate.

Add hardware abstraction layers or adapters.

Host

What/how?

Nerves Project

Dependencies

Configuration

Application Code

Hardware

Host

Test

Host

Use cases

  • Literally everywhere
  • Testing
  • Except for HAL
  • Mocking HAL

 

Resources

Host

Benefits

  • Best DX
  • Shortest feedback loop
  • Separation of concerns
  • Hardware interoperability
  • Faster debugging
  • Code easier to reason about
  • Simplified tests

Drawbacks

  • More configuration
  • Mocking
  • Not actual hardware
5

SD Card

What/How?

Burning firmware to a microSD card is the most primitive workflow for Nerves.

 

Use one of: mix burn, fwup, dd, or Etcher.

SD Card

Use cases

  • Early development
  • Custom Nerves system
  • Unsupported development board/hardware
  • Device provisioning sequences

SD Card

Drawbacks

  • Cumbersome
  • Interrupts "flow"
  • Wears out SD cards

Benefits

  • Ensures fresh firmware
  • Sometimes it's faster than WiFi

 

5.25"
5.25"
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Serial Cable

What/How?

Allows you to open a direct console connection to the Nerves target through a terminal emulator like screen.

Serial Cable

Use cases

  • Early development
  • Firmware debugging
  • Hardware debugging

Can I help?

Serial Cable

Drawbacks

  • Wires
  • Confusing tx/rx
  • Impaired console
  • Not always available

Benefits

  • See console output immediately
  • No networking or configuration!

 

HDMI Cable

What/How?

Some Nerves targets include micro HDMI or mini HDMI ports that you can connect directly to an external display.

HDMI Cable

Use cases

  • Early development
  • Hardware debugging
  • Kiosks

HDMI Cable

Warning

  • May require config

Benefits

  • See console output early
  • No networking or configuration!*

Drawbacks

  • Wires
  • Not always available

USB Cable

What/How?

The suggested path of least resistance for connecting to a Nerves target in the official Getting Started guide.

USB Cable

Use cases

  • New to Nerves
  • Early development
  • Other options unavailable

USB Cable

Drawbacks

  • Wires
  • Requires DATA cable, not just power

Benefits

  • Fast, easy, convenient
  • Supplies both power and data
25

WiFi

What/How?

Nerves targets can be configured to connect to WiFi.

OTA firmware updates via nerves_ssh.

Vintage Net supports a myriad of WiFi configurations.

WiFi

Use cases

  • Hobby projects
  • Prototyping
  • Commercial use

WiFi

Drawbacks

  • Even with Vintage Net, wireless networking may present confusing situations.

Benefits

40

IEx

What/How?

An interactive shell or REPL for Elixir.

Nerves enables IEx sessions over ssh.

IEx

Use cases

  • Host development
  • Testing during development
  • Remote shell sessions
  • Pretty much anytime!

IEx

Warning

  • Use caution when changing code in memory

Benefits

Hotswap

What/How?

Enables fast and easy OTA updates to Nerves targets.

kentaro/mix_tasks_upload_hotswap

Passes compiled modules to IEx.Helpers.nl/2, which leverages Erlang's rpc:call to load new BEAM code.

Hotswap

Use cases

  • Firmware development
  • Hardware hacking
  • Debugging application startup

Fixed it!

Hotswap

Drawbacks

  • All modules replaced each time
  • Doesn't support changes to config or deps

Benefits

  • No wires!
  • Tight feedback loop
  • Relatively easy to setup
  • Great DX with OTP

Warning

  • May present confusing situations
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OTP

What/How?

A special blend of powerful abstractions rolled into a small set of battle-tested Erlang libraries. Including the classics like supervisors, processes, links, and GenServer.

OTP

Use cases

  • Concurrent process management
  • Tweaking startup sequences
  • Designing supervision trees
  • Debugging failure conditions

OTP

Drawbacks?

Benefits

  • Fault tolerant, self-healing
  • Direct control over process restarts
  • Great DX with Hotswap or IEx
  • Process inspection and communication

Livebook

What/How?

A library for managing live, interactive, and collaborative code notebooks. Get started by downloading a pre-built firmware release that includes Livebook and some demo notebooks.

https://livebook.dev/

livebook-dev/nerves_livebook

Livebook

Use cases

  • Experimenting with new hardware
  • Documentation and guides
  • Onboarding developers
  • Demos!

Livebook

Warnings

Benefits

  • It's a live coding journal that runs on Nerves!
  • Collaborative
  • Reproducible
  • Tight feedback loop

NervesHub

What/How?

"An open-source firmware updates server"...

Also includes:

Install on AWS with nerves-hub/terraform repo.

Run as separate services on another platform.

NervesHub

Use cases

  • Commercial IoT
  • Consultancy
  • Community

NervesHub

Drawbacks

  • Community hosted version no longer available
  • Hard to configure self-hosted Nerves Hub

Benefits

  • OTA updates
  • Products
  • Deployments
  • Tags
  • Remote IEx
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Workflows:

  • Host
  • SD Card
  • Serial Cable
  • HDMI Cable
  • USB Cable

 

  • WiFi
  • IEx
  • Hotswap
  • OTP
  • Livebook
  • NervesHub

Rewind Recap

Advanced Workflows:

 

Thoughts? Questions?

How are you using Nerves?

Thanks!

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