Xiaomi Temperature Sensor

This page is for “Xiaomi Temperature Sensor” - LYWSD03MMC with custom firmware for enhanced functionality.

Commentary

I use the Xiaomi Temperature Sensor (LYWSD03MMC) with custom firmware from ATC_MiThermometer to enhance its capabilities beyond the stock firmware limitations. The custom firmware provides better control, improved display options, and enhanced functionality.

Current Usage: I don’t sync temperature data to a central dashboard yet - it’s primarily used for visual value at this point. The device works properly for local temperature and humidity monitoring with the custom firmware providing a better user experience and more reliable operation.

Custom Firmware Benefits: Enhanced display options, better battery management, improved sensor accuracy, and additional configuration options that aren’t available in the stock firmware.

Technical Specs

Hardware Specifications

• Model: LYWSD03MMC (Xiaomi Temperature Sensor)
• Sensor: SHTV3/SHTC3/SHT4x temperature and humidity sensor
• Range: -40°C to +125°C temperature, 0-100% humidity
• Accuracy: ±0.3°C temperature, ±3% humidity
• Connectivity: Bluetooth Low Energy (BLE)
• Battery: CR2032 coin cell (1 year life)
• Dimensions: 43 x 43 x 12.5 mm
• Weight: 22g

Custom Firmware Features

• Enhanced Display: Better LCD control and display options
• Improved Battery Management: Optimized power consumption
• Advanced Configuration: More sensor and device settings
• Better Accuracy: Enhanced sensor calibration and readings
• Extended Functionality: Additional features not available in stock firmware

Useful Applications

Custom Firmware Setup

• ATC_MiThermometer - Custom firmware from pvvx/ATC_MiThermometer
• Web-based Flasher - OTA firmware updates via web interface
• Telink Flasher - Hardware programming tools
• Python Interface - Custom control and configuration

Current Usage (Visual Monitoring)

• Local Display - Primary use for visual temperature and humidity readings
• No Central Dashboard - Currently not syncing to centralized monitoring
• Standalone Operation - Works independently for local environmental monitoring
• Visual Value - Provides immediate visual feedback on environmental conditions

Potential Future Integration

• Home Assistant - Open source home automation platform
• Home Assistant - Open source home automation
• OpenHAB - Home automation platform
• Node-RED - Visual programming for IoT
• MQTT - Message queuing for data transmission
• REST API - Programmatic access to sensor data

Tips and Tricks

Custom Firmware Installation

• Web-based Flashing: Use the web interface for easy firmware updates
• Hardware Requirements: USB-COM adapter for hardware flashing if needed
• Backup Original: Always backup original firmware before flashing
• Version Compatibility: Check hardware version (B1.4, B1.5, B1.6, etc.) for compatibility

Optimal Usage

• Placement: Place sensor away from heat sources for accurate readings
• Visual Monitoring: Use for immediate visual feedback on environmental conditions
• Battery Management: Monitor battery level and replace CR2032 when needed
• Multiple Sensors: Use multiple sensors for different rooms or locations

Custom Firmware Benefits

• Enhanced Display: Better LCD control and display options
• Improved Accuracy: Enhanced sensor calibration and readings
• Extended Battery Life: Optimized power consumption
• Advanced Configuration: More sensor and device settings available

Future Integration Planning

• Home Assistant: Consider integration for centralized monitoring
• Data Logging: Plan for historical data collection and analysis
• Automation: Set up automation based on temperature thresholds
• Dashboard Integration: Future central dashboard for multiple sensors

Reference material

• ATC_MiThermometer Custom Firmware
• ATC_MiThermometer Documentation