What is Nerves?

A set Elixir libraries for embedded hardware development.

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

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"

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
Kiosk s

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

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

No wires!
Commonly available
Vintage Net
Vintage Net Wizard

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

Interact with runtime
RingLogger
RamoopsLogger
Toolshed

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

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.