Sample: Arduino with Node-RED Dashboard

This walkthrough covers the Node-RED integration sample from Ardulink-2-Samples — controlling Arduino via a web-based dashboard using MQTT.

Architecture 

┌──────────┐  Serial ┌──────────────┐  MQTT  ┌───────────┐  HTTP  ┌──────────┐
│  Arduino │ <─────> │ ardulink-mqtt│ <────> │ Mosquitto │ <────> │ Node-RED │
│  (FW)    │         │ (bridge)     │        │ (broker)  │        │ (UI)     │
└──────────┘         └──────────────┘        └───────────┘        └──────────┘
  • Arduino — Runs the Ardulink firmware
  • ardulink-mqtt — Bridges serial/Arduino to MQTT
  • Mosquitto — MQTT message broker
  • Node-RED — Visual flow-based programming with dashboard

Prerequisites

  • Docker installed on your machine

Quick Start

1. Start Node-RED + Mosquitto

The sample includes a Docker Compose file:

cd Ardulink-2-Samples/node-red
docker-compose up -d

This starts:

  • Mosquitto MQTT broker on port 1883
  • Node-RED on port 1880

2. Start the MQTT Bridge

Connect to your Arduino (or use virtual-console for testing):

java -jar ardulink-mqtt-2.3.1.jar \
    -connection ardulink://virtual-console

3. Open the Dashboard

Navigate to http://localhost:1880/ui in your browser.

You’ll see a dashboard with controls that send commands through MQTT to the Arduino.

4. Edit the Flow

Navigate to http://localhost:1880/ to see or modify the Node-RED flow.

How It Works

Node-RED Flow

The flow consists of:

  1. MQTT In nodes — Subscribe to Arduino pin topics
  2. Dashboard widgets — Sliders, buttons, switches
  3. MQTT Out nodes — Publish commands back to Arduino

Topic Mapping

Node-RED Topic Arduino Action
ardulink/digital/13 Read/write digital pin 13
ardulink/analog/0 Read/write analog pin A0
ardulink/custom Custom messages

Building Your Own Dashboard

Add a Slider

  1. Drag an MQTT Out node to the flow
  2. Set the topic to ardulink/analog/0
  3. Connect a Slider node (range 0-1023)
  4. Deploy — moving the slider sets the Arduino’s analog pin

Add a Status Display

  1. Drag an MQTT In node, topic: ardulink/digital/13
  2. Connect to a Text or Gauge node
  3. Deploy — pin changes appear on the dashboard

Complex Dashboard

Add widgets for:

  • Motor speed sliders
  • Direction buttons
  • Sensor value gauges
  • LED status indicators
  • Temperature/humidity charts

Using with Physical Arduino

Replace the virtual-console connection with your real serial port:

java -jar ardulink-mqtt-2.3.1.jar \
    -connection "ardulink://serial?port=/dev/ttyACM0" \
    -broker "tcp://localhost:1883"

Next Steps