Qlink: Serial Command API for Arduino

Overview

Qlink is a powerful yet lightweight serial command API designed for Arduino, Raspberry Pi, PC, and other embedded systems. It streamlines communication between devices by providing a simple framework for registering and handling commands sent over a serial connection. With support for multiple parameter types (INT, FLOAT, STRING, LONG), Qlink is the ideal solution for controlling your Arduino projects from external applications written in Python, C#, or from a simple serial monitor.

Key Features

• Dynamic Command System: Easily define and register custom commands with a clean macro-based syntax (DEF and REG).
• Multi-Type Parameter Support: Natively parse integer, float, string, and long arguments from incoming serial commands.
• Simplified Responses: Send formatted strings back to the host device with a single link.response() call.
• Lightweight & Efficient: Designed for microcontrollers, Qlink has a minimal footprint and processes commands in real-time.
• Cross-Platform Control: Enables seamless control of Arduino from a PC (Windows/Linux), Mac, or Raspberry Pi.

Common Use Cases

• Controlling robots or CNC machines from a desktop application.
• Sending sensor data from Arduino to a Python script for logging or analysis.
• Creating interactive prototypes that respond to commands from a serial terminal.
• Configuring device settings (e.g., LED brightness, motor speed) on the fly without reprogramming.

Installation

The easiest way to install is directly through the Arduino IDE:

1. Open the Arduino IDE.
2. Go to Sketch > Include Library > Manage Libraries….
3. Search for “Qlink”.
4. Click the Install button.

You can also install the library manually by downloading the zip file below.

Code Example: Simple Blink Control

The following example demonstrates how to control the built-in LED on an Arduino board using a DELAY command sent over serial.

#include <Qlink.h>

int blinkInterval = 1000;  // Default blink interval
Qlink link(Serial);        // Initialize Qlink on the hardware serial port

// Define the "DELAY" command, which accepts one integer argument
DEF(DELAY, INT) {
  blinkInterval = Convert(Args[0], int);
  link.response("Blink interval updated to %d ms", blinkInterval);
}

void setup() {
  Serial.begin(9600);
  pinMode(LED_BUILTIN, OUTPUT);
  REG(link, DELAY); // Register the DELAY command
}

void loop() {
  link.loop(); // Continuously listen for incoming commands

  // Blink the LED at the current interval
  digitalWrite(LED_BUILTIN, HIGH);
  delay(blinkInterval);
  digitalWrite(LED_BUILTIN, LOW);
  delay(blinkInterval);
}

To use this, you would simply send a command like DELAY 500 from your serial monitor or application, and the LED blink rate would instantly update.

Download the Qlink Library (.zip)