LD2461 Human Presence & Trajectory Radar Sensor
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Overview
Code Examples
About LD2461 Human Presence & Trajectory Radar Sensor
The LD2461 is a 24GHz millimeter-wave radar sensor designed for advanced human presence detection and trajectory tracking. It features a 2T4R (2 transmit, 4 receive) antenna configuration, enabling it to detect up to 5 moving or stationary targets simultaneously. The sensor provides precise range and angle measurements, making it suitable for applications such as smart lighting, occupancy monitoring, and security systems. For more information, refer to the official datasheet: LD2461 Datasheet.
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LD2461 Specifications
Complete technical specification details for LD2461 Human Presence & Trajectory Radar Sensor
📊 Technical Parameters
LD2461 Pinout
The **LD2461** is a 5-pin 24GHz mmWave sensor with advanced 2T4R antenna and 5-target tracking:
Visual Pinout Diagram
Pin Types
Quick Tips
**Interface**: UART (256000 baud),📡 **Technology**: 24GHz FMCW radar with 2T4R antenna (2 transmit, 4 receive),👥 **Multi-Target**: Tracks up to 5 moving or stationary targets simultaneously,📍 **Precision**: Range and angle measurements for trajectory tracking
**Motion Data**: Position, speed, and presence for each target,📏 **Advanced Tracking**: Multi-target trajectory analysis,⚡ **Power**: 5V DC (OUT signal is 3.3V logic)
**OUT Logic**: 3.3V compatible, safe for ESP32 GPIO,🎯 **Applications**: Occupancy monitoring, security systems, smart lighting, gesture detection,📊 **High Data Rate**: Requires stable power and UART for multi-target streaming
Pin Descriptions
| Pin Name | Type | Description | Notes |
|---|---|---|---|
1 VCC | Power | Power input | 5V DC regulated power supply |
2 GND | Power | Ground connection | |
3 TX | Communication | UART transmit | Sends trajectory data (connect to ESP32 RX) |
4 RX | Communication | UART receive | Receives commands (connect to ESP32 TX) |
5 OUT | Communication | Digital presence output | 3.3V HIGH when presence detected (optional) |
Wiring LD2461 to ESP32
To interface the **LD2461** with an **ESP32** for trajectory tracking via UART:
Visual Wiring Diagram
Connection Status
Protocol
Pin Connections
| LD2461 Pin | Connection | ESP32 Pin | Description |
|---|---|---|---|
1 VCC Required | 5V | Power supply (5V regulated and stable) | |
2 GND Required | GND | Ground | |
3 TX Required | GPIO16 (RX2) | Sensor transmit to ESP32 receive | |
4 RX Required | GPIO17 (TX2) | Sensor receive from ESP32 transmit | |
5 OUT Optional | GPIO18 | Digital presence output (optional) |
**UART2**: Use UART2 on ESP32 (GPIO16/17 are default UART2 pins)
**Baud Rate**: 256000 bps, no parity, 1 stop bit
**Power**: Requires clean stable 5V supply (high data rate sensor)
**TX/RX**: Connect sensor TX to ESP32 RX, sensor RX to ESP32 TX
**OUT Pin**: 3.3V logic level, safe for direct ESP32 GPIO connection
**5-Target Tracking**: Streams data for up to 5 simultaneous targets
**Trajectory**: Provides position, speed, and angle data
**Data Rate**: High-speed UART - ensure no other components share UART2
**Mounting**: Secure mounting required (vibrations affect performance)
LD2461 Troubleshooting
Common issues and solutions to help you get your sensor working
Common Issues
Issue: The ESP32 receives no data from the sensor.
Ensure correct wiring: verify that TX and RX lines are properly connected, and confirm that the UART baud rate is set to 256000 bps. Also, ensure that the sensor is powered with a stable 5V supply.
Issue: The sensor does not detect presence even when someone is in range.
Check the sensor's field of view and ensure there are no obstructions. Verify that the sensor's configuration parameters are set correctly for the desired detection range and sensitivity.
Issue: Sensor intermittently detects presence or fails to maintain detection.
Ensure that the sensor is securely mounted and not subject to vibrations. Check for sources of interference in the environment that may affect radar performance.
Issue: UART component in ESPHome reports failure to initialize.
Verify that the UART pins specified in the configuration match the physical connections. Ensure that no other devices are using the same UART bus, and that the baud rate is correctly set to 256000 bps.
Debugging Tips
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.
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
LD2461 Programming Examples
Ready-to-use code examples for different platforms and frameworks
external_components:
- source:
type: git
url: https://github.com/Chreece/LD2461-ESPHome
refresh: 0s
uart:
id: uart_bus
tx_pin: GPIO17
rx_pin: GPIO16
baud_rate: 256000
ld2461:
uart_id: uart_bus
sensor:
- platform: ld2461
x:
name: "Target X Position"
y:
name: "Target Y Position"
speed:
name: "Target Speed"
target_count:
name: "Target Count"
text_sensor:
- platform: ld2461
status:
name: "LD2461 Status"As of now, there is no official ESPHome support for the LD2461 sensor. However, an external component has been developed to facilitate integration: Chreece/LD2461-ESPHome. This component is under development and may require manual configuration and testing.
from machine import UART
import time
# Initialize UART2 for LD2461 (TX=17, RX=16)
uart = UART(2, baudrate=256000, tx=17, rx=16)
buffer = b''
while True:
if uart.any():
buffer += uart.read()
if b'\n' in buffer:
lines = buffer.split(b'\n')
for line in lines[:-1]:
try:
print(line.decode('utf-8').strip())
except UnicodeDecodeError:
pass
buffer = lines[-1]
time.sleep(0.05)A MicroPython implementation for the LD2461 sensor is available, developed by marconicivitavecchia. It provides basic functionality for interfacing the sensor with an ESP32 using MicroPython. For more details and code examples, refer to the GitHub repository: esp32-LD2461.
Wrapping Up LD2461
The ESP32 LD2461 Human Presence & Trajectory Radar 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.
Best Practices
For optimal performance, ensure proper wiring and follow the recommended configuration for your chosen development platform.
Safety First
Always verify power supply requirements and pin connections before powering up your project to avoid potential damage.
Ready to Start Building?
Now that you have all the information you need, it's time to integrate the LD2461 into your ESP32 project and bring your ideas to life!
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