2 Channel GSM SMS Remote Control Relay Module (SIM800C)

Take control of your electrical devices from anywhere using SMS with this 2 Channel GSM Relay Module. Powered by the reliable SIM800C GSM module and STM32F103C8T6 microcontroller, this intelligent relay board allows you to remotely switch two independent electrical loads ON or OFF simply by sending a text message.

Designed for industrial automation, agriculture, smart farming, security systems, and remote equipment control, this module supports 9V to 36V DC input and includes two high-quality 10A relays capable of controlling AC or DC loads.

The module supports up to three authorized phone numbers, ensuring secure access while allowing users to change system passwords and monitor relay status remotely via SMS.

Whether you’re managing greenhouse irrigation, controlling oxygen pumps, operating roller shutters, or automating remote equipment, this GSM relay module provides a reliable solution without requiring Wi-Fi or Internet connectivity.

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Key Features

✔ Remote SMS control from any GSM network

✔ Dual independent 10A relay outputs

✔ Built-in SIM800C GSM module

✔ STM32F103C8T6 ARM microcontroller

✔ Wide operating voltage: 9V–36V DC

✔ Supports up to 3 authorized phone numbers

✔ Password protected system

✔ Query relay status remotely

✔ Relay state memory after power interruption

✔ External GSM antenna included

✔ Ideal for locations without Internet access

Technical Specifications

• Model: GSM SMS Remote Control Relay Module
• GSM Module: SIM800C
• Microcontroller: STM32F103C8T6
• Channels: 2
• Input Voltage: 9V–36V DC
• Recommended Supply Current: Minimum 1A
• Relay Rating: 250VAC 10A
• Communication: GSM SMS
• Authorized Users: Up to 3 phone numbers
• Relay Control: Individual ON/OFF
• Status Feedback: SMS reply
• Antenna: External GSM antenna included

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SMS Functions

Authorization

Supports up to three authorized mobile numbers for secure operation.

Password Change

Change the default system password remotely via SMS.

Relay Commands

Relay 1

• ON1 – Turn Relay 1 ON
• OFF1 – Turn Relay 1 OFF

Relay 2

• ON2 – Turn Relay 2 ON
• OFF2 – Turn Relay 2 OFF

Status Query

Send:

STA

The module replies with the current status of both relays.

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LED Status Indicators

The onboard LEDs display system operating status including:

• Power On
• System Ready
• Configuration Mode
• SMS Reception
• Fault Status

These indicators simplify troubleshooting and installation.

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Applications

This GSM relay controller is suitable for:

• Smart Greenhouses
• Farm Irrigation Systems
• Water Pumps
• Oxygen Pumps
• Remote Electrical Equipment
• Server Rooms
• Security Systems
• Access Control
• Roller Shutters
• Pet Feeding Systems
• Industrial Automation
• Remote Lighting Control

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Package Includes

• 1 × 2 Channel GSM SMS Relay Module
• 1 × GSM Antenna

2 Channel GSM SMS Remote Control Relay Module SIM800C STM32F103C8T6 9V-36V Dual 10A Relay Board 2 Channel GSM SMS Remote Control Relay Module SIM800C STM32F103C8T6 9V-36V Dual 10A Relay Board