light_weight_telemetry_system

A lightweight, real-time telemetry system for drones using an STM32 microcontroller and LoRa modules. Transmits GPS coordinates, altitude, and temperature over 500m with <5% packet loss. Ideal for UAV monitoring and data logging.

Drone Telemetry System with STM32 and LoRa

[Drone Battery (5V)] → [AMS1117 3.3V LDO]
│
├── [STM32F411]
│ ├── [LoRa (SX1276)] via SPI
│ ├── [GPS (NEO-M8N)] via UART
│ └── [BMP280] via I2C
├── [LoRa Antenna]
└── [Sensors]

Features

• Real-Time Data: GPS (latitude/longitude), barometric altitude, and temperature.
• Long Range: 500m+ line-of-sight communication using LoRa.
• Low Power: STM32 sleep modes and LoRa duty cycling.
• Lightweight: Total system weight <50g.
• <5% Packet Loss: Optimized LoRa settings with CRC checksums.

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Hardware Components

Component	Model/Specification
Microcontroller	STM32F411CEU6
LoRa Module	SX1276 (HopeRF RFM95W)
GPS Module	u-blox NEO-M8N
Altitude/Temp Sensor	BMP280
Voltage Regulator	AMS1117 3.3V LDO
Antenna	868/915 MHz Helical Antenna

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Wiring Diagram

Component	STM32 Pin	Connection Details
LoRa MOSI	PA7	SPI1_MOSI
LoRa MISO	PA6	SPI1_MISO
LoRa SCK	PA5	SPI1_SCK
LoRa NSS	PA4	GPIO (Chip Select)
LoRa RESET	PB0	GPIO (Reset)
LoRa DIO0	PB1	GPIO (Interrupt)
GPS TX	PA3	USART2_RX
GPS RX	PA2	USART2_TX (Optional)
BMP280 SDA	PB7	I2C1_SDA
BMP280 SCL	PB6	I2C1_SCL

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Software Setup

1. IDE: Install STM32CubeIDE.
2. Libraries:
   • RadioLib for LoRa communication.
   • TinyGPS++ for GPS parsing.
   • STM32 HAL drivers (auto-generated by STM32CubeMX).
3. Code Upload:
   • Clone this repository.
   • Open the project in STM32CubeIDE.
   • Build and flash to the STM32.

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Hardware Assembly

1. Solder components to a perfboard or custom PCB.
2. Connect sensors and LoRa module to the STM32 as per the wiring table.
3. Power the system from the drone’s battery via the 3.3V LDO regulator.
4. Mount the antenna away from carbon fiber parts and motors.

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Usage

1. Transmitter (Drone):
   • The STM32 reads sensor data and transmits packets via LoRa at 1 Hz.
   • Packet format: [latitude, longitude, altitude (m), temperature (°C)].
2. Receiver (Ground Station):
   • Use another LoRa module connected to an STM32
   • Decode packets and display data using a serial monitor.

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