USB Relay Module 5V 1 Channel PC Control

Specifications

• Operating Voltage: 5V DC (Powered directly from the USB port)
• Relay Capacity: 10A @ 250V AC / 10A @ 30V DC
• Channels: 1 (Single Pole Double Throw - SPDT)
• Communication Interface: USB to Serial (Standard USB Type-A Plug)
• Baud Rate: 9600 bps (Default)
• Onboard Indicators: Red Power LED, Green/Blue Relay Status LED

      Control Commands (Hex):

• Turn ON: A0 01 01 A2
• Turn OFF: A0 01 00 A1

Applications

• Automated Hardware Testing Rigs: Automatically cycle power to a Device Under Test (DUT) via automated PC scripts.
• Server Room Management: Wire it to network switches or modems to perform hard reboots remotely.
• Smart Desktop Automation: Turn on your soldering iron, desk lamps, or 3D printers directly from your computer terminal.
• Industrial Kiosks: Safely trigger external lights, sirens, or door locks from a kiosk PC.

New Capabilities

• Past Projects: You've likely mastered toggling standard 5V relays using an Arduino or ESP32, dealing with logic levels and 5V power supply constraints.
• Feature Upgrade: This module removes the middleman MCU entirely. It unlocks the ability to use your desktop PC or a Raspberry Pi as the direct brain of your power automation, allowing integration with complex desktop software or web servers.
• Effort Level: Beginner. No C++ required. If you can send a serial command via Python or PuTTY, you can use this relay.

Virtual Technician & Wiring Guide

• ⚠️ WARNING: This module handles live AC Mains Voltage (230V). Always ensure the USB is unplugged before touching the terminal blocks. If you are not experienced with AC wiring, consult a professional.
• USB Port: Plugs directly into your PC or Raspberry Pi (No external 5V supply needed).
• NC (Normally Closed): Connected to COM when the relay is OFF. Use this if you want the device to stay ON by default.
• COM (Common): The main power feed (e.g., Live wire from the wall).
• NO (Normally Open): Connected to COM only when the relay is ON. Connect your appliance here to turn it on via software.

Package Includes :

• 1 x 5V 1 channel USB Control Relay Module.

Frequently Asked Questions (FAQ)

• Does this USB relay need external power?
  No, it draws the required 5V directly from the computer's USB port.
• What are the hex commands to control the 1 channel USB relay?
  Typically, send A0 01 01 A2 to turn it ON, and A0 01 00 A1 to turn it OFF at 9600 baud rate.
• Do I need to install special drivers on Windows 10?
  Most modern OS (Windows 10/11) will auto-detect the CH340 or HID chip and assign a COM port automatically.
• How to control 5v usb relay with Python?
  You can use the pyserial library to open the assigned COM port and send the hex bytearray directly to the module.
• Can I use this relay module with a Raspberry Pi?
  Yes, it functions identically on Linux/Raspberry Pi. It will show up as a /dev/ttyUSB device.
• Can this relay switch a 230V AC water pump?
  It can switch up to 10A at 250V AC. Ensure your pump's starting current does not exceed 10A (approx 2200W resistive, but inductive loads like pumps should be kept under 1000W).
• What is the default baud rate for the serial connection?
  The default baud rate is strictly 9600 bps, 8 data bits, no parity, 1 stop bit.
• Will this work on macOS?
  Yes, provided you have the correct USB-to-Serial drivers installed for macOS.
• What do the LEDs on the board indicate?
  The Red LED indicates that the board is receiving 5V USB power. The Green/Blue LED turns on when the relay coil is energized (NO and COM are connected).
• Can I plug multiple USB relays into one computer?
  Yes, you can plug in multiple modules. They will simply be assigned different COM port numbers (e.g., COM3, COM4).
• Is there optical isolation on this USB relay?
  No, standard 1-channel USB relays usually lack opto-isolation. The relay itself provides physical electromechanical isolation between the PC and the high voltage.
• What happens if my PC goes to sleep or reboots?
  The USB port will likely drop power. The relay will lose power and revert to its default "Normally Closed" state.
• How do I wire a light bulb to the relay?
  Cut the LIVE wire of the bulb. Put one end in the COM terminal and the other in the NO terminal. Neutral goes directly to the bulb.
• Is the relay normally open or normally closed out of the box?
  It features both. The screw terminals provide access to NO (Normally Open) and NC (Normally Closed).
• What chip does the USB relay use for communication?
  It generally utilizes a dedicated 8-bit microcontroller paired with a CH340 or similar serial IC.
• Can I control the relay using a web server?
  Yes, you can write a backend script (Node.js, Python Flask) that listens for HTTP requests and sends the serial commands to the relay.
• Is it safe to leave this relay turned on 24/7?
  Yes, the relay is rated for continuous operation, provided the load remains well within the 10A limit.