arduino-development

name: arduino-development description: This skill should be used when the user asks to "create an Arduino project", "program an Arduino", "write Arduino code", "upload to Arduino", "compile Arduino sketch", "use arduino-cli", "blink an LED", "read a sensor", mentions "microcontroller programming", "embedded development with Arduino", "Arduino Uno", "Arduino Nano", "Arduino Mega", "ESP32 with Arduino", "ESP8266", "Adafruit board", or discusses IoT prototyping, sensor projects, servo control, or Arduino library usage. version: 1.0.0

Arduino Development

Guidance for Arduino development using the arduino-cli command-line tool (v1.4.1).

Core Workflow

Every Arduino project follows this sequence:

1. Detect the board: Run arduino-cli board list to identify connected hardware. The output includes the port address and FQBN (Fully Qualified Board Name) needed for all subsequent steps.

2. Install the platform core: Each board family requires a platform core. Extract the core ID from the FQBN (first two colon-separated segments, e.g., arduino:avr from arduino:avr:uno). Install with arduino-cli core install <core-id>.

3. Create the sketch: Run arduino-cli sketch new <Name>. This creates a directory with a .ino file containing empty setup() and loop() functions. The directory name must match the .ino filename.

4. Write the code: Edit the .ino file. Every sketch requires:

   • void setup() -- runs once at power-on/reset
   • void loop() -- runs repeatedly after setup

5. Compile: Run arduino-cli compile --fqbn <FQBN> <sketch-dir>. The output reports flash and RAM usage.

6. Upload: Run arduino-cli upload -p <port> --fqbn <FQBN> <sketch-dir>. Some boards require pressing a reset button before upload.

7. Monitor (optional): Run arduino-cli monitor -p <port> to view Serial output. Default baud rate is 9600.

Available Slash Commands

Use these commands for streamlined workflows:

• /arduino-new <name> -- Create a new sketch
• /arduino-build [path] [--fqbn <FQBN>] -- Compile a sketch
• /arduino-upload [path] -- Upload to a connected board
• /arduino-boards [search] -- List boards or search for board support
• /arduino-libs <search | install name> -- Find or install libraries

Arduino Sketch Structure

A minimal sketch:

void setup() {
  Serial.begin(9600);
  pinMode(LED_BUILTIN, OUTPUT);
}

void loop() {
  digitalWrite(LED_BUILTIN, HIGH);
  delay(1000);
  digitalWrite(LED_BUILTIN, LOW);
  delay(1000);
}

Key conventions:

• Pin constants: LED_BUILTIN, A0-A5, D0-D13
• Serial communication: Serial.begin(baud), Serial.println(data)
• Digital I/O: pinMode(), digitalWrite(), digitalRead()
• Analog I/O: analogRead(), analogWrite() (PWM)
• Timing: delay(ms), millis(), micros()
• Prefer millis() over delay() for non-blocking timing

Multi-File Projects

For larger projects, place additional files alongside the .ino:

MyProject/
├── MyProject.ino       # Main sketch (must match dir name)
├── sensors.h           # Header for sensor module
├── sensors.cpp         # Sensor implementation
└── config.h            # Configuration constants

All .ino, .c, .cpp, .h files in the sketch directory are automatically compiled together. Use #include "file.h" for local headers.

Library Management

• Search: arduino-cli lib search <keyword>
• Install: arduino-cli lib install "<Library Name>"
• List installed: arduino-cli lib list
• Include with: #include <LibraryName.h>

3rd Party Board Support

Boards like ESP32, ESP8266, and Adafruit require additional board manager URLs. Configure with:

arduino-cli config set board_manager.additional_urls <URL1>,<URL2>

Then run arduino-cli core update-index to refresh.

Additional Resources

For detailed board-to-FQBN-to-core mappings, consult:

• references/board-platforms.md -- Common boards, FQBNs, cores, and board manager URLs

For common compilation and upload errors, consult:

• references/troubleshooting.md -- Error diagnosis and fixes

For advanced project structure patterns, consult:

• references/project-patterns.md -- State machines, non-blocking timing, multi-file organization

Important Notes

• Use --json flag when parsing arduino-cli output programmatically
• The board list command shows Bluetooth and debug serial ports too; only entries with matching_boards in the JSON represent actual Arduino devices
• Some boards (ESP32, STM32) require additional board manager URLs
• On macOS, serial ports appear as /dev/cu.usbmodem* or /dev/cu.usbserial*