ESP32 LD2410S Human Presence Sensor
Overview
The LD2410S is an ultra-low-power 24GHz mmWave radar sensor for human presence detection, supporting both stationary and moving target detection. It uses a unique UART communication protocol at 115200 baud and operates at 3.3V, making it ideal for battery-powered smart home automation systems.
About LD2410S Human Presence Sensor
The LD2410S is an ultra-low-power 24GHz mmWave radar sensor designed for human presence detection. It operates at 3.3V and consumes approximately 0.1mA, making it ideal for battery-powered applications. Unlike other LD2410 variants, the LD2410S uses a different UART communication protocol with a baud rate of 115200. It can detect both moving and stationary human targets within a range of up to 8 meters. For more information on the LD2410 series, see LD2410.
Where to Buy
Starting from
$8 per unit
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Technical Specifications
Pinout Configuration
The VCC pin is used to supply power to the sensor, and it typically requires 3.3V or 5V (refer to the datasheet for specific voltage requirements). The GND pin is the ground connection and must be connected to the ground of your ESP32.
The LD2410S module is a compact, ultra-low-power radar sensor designed for energy-efficient human presence detection. It operates at 3.3V and provides UART-based communication along with an optional digital output pin. The pin definitions are as follows:
3V3– Power input pin. Connect to a regulated 3.3V source. Supplying the correct voltage is critical to avoid damaging the sensor.GND– Ground reference. Connect this to the ground pin of the ESP32 or host controller to complete the circuit and ensure signal stability.TX– UART transmit pin. Sends data from the LD2410S to the microcontroller (connect to ESP32 RX).RX– UART receive pin. Receives commands from the microcontroller (connect to ESP32 TX).OUT– Optional digital output that goes HIGH when presence is detected. Operates at 3.3V logic level and can be used for interrupt-driven designs or to trigger external logic.
Note: Due to its lower voltage requirement, this sensor is ideal for battery-powered or mobile ESP32 applications. Ensure all connections are made with 3.3V logic-compatible devices.
Wiring with ESP32
The following wiring instructions demonstrate how to interface the LD2410S radar sensor with an ESP32 using UART communication. This setup is based on UART2 (GPIO16/17) for asynchronous serial input/output:
3V3(red wire) → 3.3V pin on the ESP32. Do not connect to 5V as this may permanently damage the sensor.GND(black wire) → GND on ESP32. A solid ground connection is necessary for reliable UART data transfer.TX(green wire) → GPIO16 (RX on ESP32). This wire sends serial data from the LD2410S to the ESP32.RX(blue wire) → GPIO17 (TX on ESP32). This pin allows the ESP32 to send configuration commands to the sensor.OUT(yellow wire, optional) → GPIO18 if you're using the digital output for real-time hardware presence detection or interrupts.
Ensure the UART baud rate is configured to 115200 bps and that UART2 is properly defined in your firmware. All wiring should use 3.3V logic-compatible lines, as the LD2410S is not 5V tolerant.
Troubleshooting Guide
Common Issues
🚫 No Data Received
Issue: The ESP32 receives no data from the sensor.
Ensure correct wiring: swap TX and RX if needed, and confirm baud rate is set to 115200. Verify power is supplied at 3.3V.
❌ Presence Not Detected
Issue: The sensor does not detect presence even when someone is in range.
Check detection parameters using the LD2410S configuration tool. Ensure UART communication is functioning correctly.
⚠️ Intermittent Detection
Issue: Sensor intermittently detects presence or fails to maintain detection.
Adjust detection thresholds using the configuration tool. Reposition sensor to minimize obstructions.
🔌 UART Initialization Fails
Issue: UART component in ESPHome reports failure to initialize.
Verify UART pins are correct, baud rate is 115200, and no other component is using the same UART bus.
Debugging Tips
🔍 Serial Monitor
Use the Serial Monitor to check for error messages and verify the sensor's output. Add debug prints in your code to track the sensor's state.
⚡ Voltage Checks
Use a multimeter to verify voltage levels and check for continuity in your connections. Ensure the power supply is stable and within the sensor's requirements.
Additional Resources
Code Examples
Arduino Example
As of now, there is no official Arduino library available for the LD2410S sensor. Due to its unique UART communication protocol at 115200 baud, existing LD2410 libraries are incompatible. Developers interested in integrating the LD2410S with Arduino are advised to refer to the sensor's datasheet and implement custom UART communication handling based on the provided protocol specifications.
ESPHome Example
The LD2410S sensor is not currently supported by the official ESPHome LD2410 component due to its different UART protocol and baud rate of 115200. However, there is a custom ESPHome component available that provides preliminary support for the LD2410S. You can find this custom component at MrUndead1996/ld2410s-esphome. Please note that this is a community-developed solution and may require additional configuration and testing.
PlatformIO Example
Currently, there is no official PlatformIO library available for the LD2410S sensor. Developers aiming to integrate the LD2410S with PlatformIO should refer to the sensor's datasheet and implement custom UART communication handling based on the provided protocol specifications.
MicroPython Example
At present, there is no official MicroPython library for the LD2410S sensor. Due to its unique UART communication protocol at 115200 baud, existing LD2410 libraries are incompatible. Developers interested in integrating the LD2410S with MicroPython are advised to refer to the sensor's datasheet and implement custom UART communication handling based on the provided protocol specifications.
Conclusion
The ESP32 LD2410S Human Presence Sensor is a powerful Human Presence sensor that offers excellent performance and reliability. With support for multiple development platforms including Arduino, ESP-IDF, ESPHome, PlatformIO, and MicroPython, it's a versatile choice for your IoT projects.
For optimal performance, ensure proper wiring and follow the recommended configuration for your chosen development platform.
Always verify power supply requirements and pin connections before powering up your project to avoid potential damage.
