Building Fault-Tolerant IoT Systems with Elixir and Nerves

Sep 23, 2025 8 min

The world of embedded systems and IoT development has traditionally been dominated by C, C++, and more recently, Python and JavaScript. However, a new player is emerging that brings unprecedented reliability and concurrency to the embedded space: Elixir with the Nerves framework.

What Makes Elixir Special for Embedded Systems?

Elixir, built on the battle-tested Erlang Virtual Machine (BEAM), was designed from the ground up for building fault-tolerant, concurrent, and distributed systems. These characteristics, originally developed for telecommunications infrastructure that required 99.9% uptime, translate perfectly to the challenges of modern IoT development.

The Actor Model in Practice

Elixir’s lightweight processes (actors) are not OS threads—they’re isolated units of computation that communicate through message passing. In an embedded context, this means:

# Each sensor can run in its own process
defmodule SensorReader do
  use GenServer

  def start_link(sensor_type) do
    GenServer.start_link(__MODULE__, sensor_type, name: sensor_type)
  end

  def init(sensor_type) do
    schedule_reading()
    {:ok, %{sensor: sensor_type, last_reading: nil}}
  end

  def handle_info(:read_sensor, state) do
    reading = read_sensor_data(state.sensor)
    broadcast_reading(reading)
    schedule_reading()
    {:noreply, %{state | last_reading: reading}}
  end

  defp schedule_reading do
    Process.send_after(self(), :read_sensor, 5000)  # Read every 5 seconds
  end
end

If one sensor fails, it doesn’t bring down the entire system—a critical advantage in remote IoT deployments where physical access might be limited.

”Let It Crash” Philosophy

Traditional embedded programming often involves defensive coding to prevent crashes. Elixir takes the opposite approach: design for failure and recover gracefully. Supervision trees automatically restart failed processes, maintaining system stability:

defmodule WeatherStation.Supervisor do
  use Supervisor

  def start_link(_) do
    Supervisor.start_link(__MODULE__, :ok, name: __MODULE__)
  end

  def init(:ok) do
    children = [
      {SensorReader, :temperature},
      {SensorReader, :humidity},
      {SensorReader, :pressure},
      DataPublisher
    ]

    Supervisor.init(children, strategy: :one_for_one)
  end
end

Enter Nerves: Elixir for Embedded

Nerves is a framework that brings Elixir’s power to embedded devices by creating minimal, purpose-built Linux systems. Instead of running a full desktop Linux distribution, Nerves creates a custom system containing only what your application needs.

Key Nerves Advantages

Minimal Footprint: A basic Nerves system can run in as little as 32MB of storage, making it suitable for resource-constrained devices.

Over-the-Air Updates: Deploy new code to remote devices without physical access:

# Update firmware remotely
NervesHub.update_firmware("new_version.fw")

Cross-Compilation: Develop on your laptop, deploy to ARM-based devices seamlessly.

Hardware Integration: Direct access to GPIO, I2C, SPI, and other hardware interfaces:

defmodule TemperatureSensor do
  alias Circuits.I2C

  def read_temperature do
    {:ok, i2c} = I2C.open("i2c-1")
    I2C.write_read(i2c, 0x48, <<0x00>>, 2)
    |> parse_temperature()
  end
end

Real-World Use Cases

Industrial Monitoring

Nerves excels in industrial environments where reliability is paramount. A manufacturing plant can deploy hundreds of sensors that monitor equipment health, with each sensor running in its own supervised process. If network connectivity drops, the system continues collecting data locally and synchronizes when connectivity returns.

Agricultural IoT

Smart farming applications benefit from Nerves’ fault tolerance. Soil moisture sensors, weather stations, and irrigation controllers can operate independently while coordinating through a central Phoenix LiveView dashboard for real-time monitoring.

Smart Home Integration

Home automation systems built with Nerves can integrate multiple protocols (Zigbee, Z-Wave, WiFi) while maintaining responsiveness. The concurrent nature of Elixir means handling multiple device communications simultaneously without blocking.

Development Workflow

Getting started with Nerves is surprisingly straightforward:

# Create a new Nerves project
mix nerves.new weather_station
cd weather_station

# Configure for Raspberry Pi
export MIX_TARGET=rpi4

# Install dependencies and build firmware
mix deps.get
mix firmware

# Burn to SD card
mix burn

The development cycle is fast: write code, compile firmware, and deploy to hardware in minutes rather than hours.

Integration with Phoenix

One of Nerves’ most powerful features is seamless integration with Phoenix web applications. You can build a complete IoT solution where:

  • Nerves devices collect and process sensor data
  • Phoenix backend aggregates data from multiple devices
  • LiveView frontend provides real-time visualization
# In your Nerves device
defmodule SensorData.Publisher do
  def send_reading(data) do
    HTTPoison.post(
      "https://your-phoenix-app.com/api/readings",
      Jason.encode!(data),
      [{"Content-Type", "application/json"}]
    )
  end
end

# In your Phoenix LiveView
def handle_info({:new_reading, data}, socket) do
  {:noreply, push_event(socket, "update-chart", data)}
end

Performance Considerations

While Elixir isn’t as fast as C for pure computational tasks, the trade-offs often favor development speed and system reliability. For most IoT applications, the bottleneck is I/O (network, sensors) rather than CPU, making Elixir’s concurrent model ideal.

Benchmarks show Nerves systems can handle thousands of concurrent sensor readings while maintaining sub-millisecond response times for critical operations.

The Future of Embedded Development

As IoT devices become more complex and interconnected, the traditional approaches of embedded development are showing their limitations. Systems need to handle:

  • Multiple communication protocols
  • Real-time data processing
  • Remote updates and monitoring
  • Fault recovery without human intervention

Elixir and Nerves address these challenges by bringing decades of telecom reliability engineering to the embedded world. The result is IoT systems that are not just functional, but truly robust and maintainable.

Getting Started

The best way to understand Nerves is to build something. Start with a simple temperature sensor project, then expand to include web connectivity and remote monitoring. The official Nerves documentation provides excellent tutorials for beginners.

The future of IoT is not just connected devices—it’s reliable, self-healing systems that can operate independently while coordinating intelligently. With Elixir and Nerves, that future is available today.

Interested in learning more about building IoT systems with Elixir? Check out my Nerves Weather Station project for a complete example of multi-application IoT development.

~Norman Argueta