🌐 Project Overview

TELEGUARD v1.0 is a highly reliable, industrial-grade IoT controller and monitoring board designed specifically for harsh environments where standard consumer electronics fail. Built around a robust STM32 architecture, it serves as a bulletproof platform for remote monitoring, telemetry, water leak detection, and high-voltage signal analysis via the GSM network.

🧠 Processing & Connectivity

• Microcontroller: Powered by the STMicroelectronics STM32G030F6P6 ARM Cortex-M0+ MCU, providing efficient processing and a robust hardware watchdog.
• GSM Telemetry: Equipped with the Quectel M08R GSM module for reliable SMS and data connectivity. Note: The footprint is pin-to-pin compatible with the SIM800C, allowing developers to assemble and use either module based on their local availability.
• Onboard Data Storage: Features an onboard I2C EEPROM for saving system states, configurations, or logs.

• ⚠️ Firmware Developer Note: To optimize space, external I2C pull-up resistors are omitted from the PCB layout. Firmware developers must enable the STM32's internal pull-up resistors on the respective I2C pins for proper EEPROM communication.

⚡ Industrial I/O & Galvanic Isolation

• 220V AC Mains Detection: Features two dedicated high-voltage inputs capable of safely detecting 220V AC signals.
• Universal Sensor Input: Includes a versatile input channel that supports a wide variety of standard analog or digital sensors (e.g., water leak probes, temperature sensors, limit switches).
• 100% Galvanic Isolation: All input channels are strictly isolated from the main logic circuit using optocouplers, ensuring MCU safety against voltage spikes.
• Isolated Relay Output: Features one onboard 12V SPDT relay for switching heavy external loads. The relay is isolated via an optocoupler, and a physical PCB cutout (milling slot) is implemented under the relay to maximize creepage distance and separate the high-voltage traces from the low-voltage logic.

🛡️ Bulletproof Power Architecture & Protection

• High-Efficiency Switching Regulator: At the heart of the power stage is the Texas Instruments TPS54360 industrial step-down (buck) converter. This ensures a rock-solid, high-current supply for the GSM module, easily handling the demanding 2A peak transmission bursts without voltage drops, brownouts, or network disconnects.
• Power Supply: Designed to be powered by a standard 12V DC Adapter (minimum 2.5A recommended) via the onboard DC barrel jack.
• Triple-Layer Input Protection: The main power input is heavily guarded against overvoltage surges and overcurrent events using a combination of a Varistor (VDR), a TVS diode, and a fast-acting SMD fuse.
• Reverse Polarity Protection: A dedicated high-current Schottky diode completely protects the board from accidental reverse-polarity connections.
• Safe Sensor Powering: The power output terminal provided for external sensors is strictly current-limited. A PTC resettable fuse is integrated to cap the output at a maximum of 200mA, preventing external short-circuits from bringing down the main board.
• ESD Protection: Highly sensitive interfaces, particularly the SIM card socket, are protected by specialized TVS diode arrays to suppress Electrostatic Discharge (ESD).

📐 PCB Design & EMI Immunity

This board is not a simple prototype; it is designed for production. The PCB routing strictly adheres to industrial design rules. Proper ground planes (Polygon pours), component separation, and trace width calculations have been implemented to ensure excellent Electromagnetic Interference (EMI) immunity and noise resistance in industrial factory settings.