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Arduino Code and Video for PowerShell Command-Line Control of a Relay via USB

In this tutorial, we will explore how to control a relay using an Arduino and a USB to UART module, all through Windows PowerShell commands. This setup allows you to turn a light on and off remotely by sending specific commands via the command line. By the end of this guide, you'll have a working system that can control AC devices safely and effectively.

We will be utilizing the Arduino's serial communication capabilities to listen for commands sent from PowerShell. The specific commands used will be integers that correspond to turning the relay on and off. This project requires careful handling of AC voltage, so safety precautions must be observed throughout the process. For additional clarification, be sure to watch the full video (in video at 00:00).

Hardware Explained

The main components involved in this project include the Arduino board, the USB to UART module, and the relay. The Arduino acts as the brain of the operation, processing serial commands and controlling the relay accordingly. The USB to UART module facilitates communication between the Arduino and your computer, enabling command input through PowerShell.

The relay serves as a switch that controls the flow of electricity to the light. When the relay is activated, it closes the circuit, allowing current to flow and the light to turn on. When deactivated, it opens the circuit, cutting off the power and turning the light off. This allows for safe control of high-voltage devices from a low-voltage system.

Datasheet Details

• Ensure proper voltage levels for the relay and UART module.
• Use a heat sink if the relay is expected to handle high loads.
• Double-check all connections before powering the system.
• Keep the module away from moisture and conductive materials.
• Utilize common grounding for all components to avoid voltage spikes.

Wiring Instructions

Begin by connecting the VCC pin of the relay module to the 5V pin on the Arduino. Next, connect the GND pin of the relay to one of the ground pins on the Arduino. The control pin (labeled as IN or similar) from the relay should be connected to digital pin 8 on the Arduino.

For the USB to UART module, connect the TX pin to the RX pin of the Arduino and the RX pin of the module to the TX pin of the Arduino. Be sure to connect the ground pin of the USB module to the same ground as the Arduino to ensure a common reference. This setup allows for seamless communication between the Arduino and your computer through PowerShell.

Code Examples & Walkthrough

byte RX_Value = 0;        // stores received byte
#define relay 8 // pin 8 for relay
int comON = 6; // code to turn ON the light
int comOFF = 2; // code to turn OFF the light

In this excerpt, we define the variable RX_Value to hold the received command from the serial monitor. The relay is set to pin 8, and we define two commands: comON for turning the light on and comOFF for turning it off.

void setup() {
  Serial.begin(9600); // Start serial communication at 9600 baud
  pinMode(relay, OUTPUT); // Set relay pin as output
  digitalWrite(relay, HIGH); // Turn the relay OFF initially
}

In the setup() function, we initialize serial communication at 9600 baud, which must match the settings in PowerShell. The relay pin is configured as an output, and we set it to HIGH to ensure the relay is off when the program starts.

if (Serial.available()) {
    RX_Value = Serial.read(); // Read the incoming byte
    if (RX_Value == comON) {
        digitalWrite(relay, LOW); // Turn the relay ON
    } else if (RX_Value == comOFF) {
        digitalWrite(relay, HIGH); // Turn the relay OFF
    }
}

This code snippet demonstrates how the program listens for incoming serial data. If a command is received that matches comON, the relay is activated, turning the light on. Conversely, if comOFF is received, the relay is deactivated, turning the light off. This loop continues, allowing for responsive control from PowerShell.

Demonstration / What to Expect

When the setup is complete and the code is uploaded, you should be able to open PowerShell and send the commands to control the light. Typing the corresponding command should immediately trigger the relay, turning the light on or off as desired. Be cautious when handling AC devices, ensuring no live wires are exposed during testing.

Video Timestamps

• 00:00 - Introduction and overview of the project
• 02:30 - Wiring explanation
• 05:00 - Code walkthrough
• 08:15 - PowerShell command demonstration
• 10:45 - Conclusion and safety tips

图像

Wirig relay module to AC load

FT232-AZ-USB-to_TTL-serial-adapter

Arduino wiring for FTDI usb with relay

CP2102 usb to UART with relay

CP2102 usb to UART with relay

CP2102 usb to UART with relay

Arduino wiring for CP2102 usb to UART with relay

Wirig relay module to AC load

FT232-AZ-USB-to_TTL-serial-adapter

Arduino wiring for FTDI usb with relay

CP2102 usb to UART with relay

CP2102 usb to UART with relay

CP2102 usb to UART with relay

Arduino wiring for CP2102 usb to UART with relay

++
/*
 * This Arduino code is to read and decode serial monitor
 * code sent from USB to UART or USB to UART FTDI chip
 * commands sent from Windows PowerShell or other systems commands.
 * When the code is detected and matched with the present codes
 * for example, 6 is to turn the relay ON and 2 to turn OFF the relay,
 * in turn, will turn ON the AC bulb.
 Watch the video for this code: https://youtu.be/HzLCkzX5q3w
 * 
 */
// Written by Ahmad S. Robojax at 19:11 on Saturday, April 01, 2018
byte RX_Value = 0;        // stores received byte

#define relay 8 // pin 8 for relay

int comON = 6;//code to turn ON the light
int comOFF = 2;// code to turn OFF the light

void setup() {
  // Robojax code for USB command to Relay
  Serial.begin(9600);
  while (!Serial) {
    ; // wait for serial port to connect. Needed for native USB port only
  }

  pinMode(relay,OUTPUT);// define pin 8 as output
  digitalWrite(relay,HIGH);// turn the relay OFF
  Serial.println("Robojax USB Command");
}

void loop() { // run over and over
  // Robojax code for USB command to Relay
  if (Serial.available()) {


    RX_Value = Serial.read();
    if(Serial.read() == comON)
    {
          digitalWrite(relay,LOW);// turn the relay ON
          Serial.print("Code to Turn ON:");
          Serial.println(RX_Value);// print the received command
    }
    if(RX_Value == comOFF)
    {
         digitalWrite(relay,HIGH);// turn the relay OFF
         Serial.print("Code to Turn OFF:");
         Serial.println(RX_Value); // print the received command     
    }

  }
}// loop