BoardPilotHLK-LD2420 mmWave presence radar with ESP32
Supply 3.3 V
Bus GPIO
Measures presence, distance
Pins and ESP32 wiring
| Pin | Role | ESP32 pin | Notes |
|---|---|---|---|
| 3V3 | Power | 3V3 | Needs 3.3 V. Pin order may differ by board revision: check the silkscreen |
| GND | Ground | GND | |
| OT1 | Output (the part drives it) | D25 | UART TX of the radar. Connect to an ESP32 RX pin (115200 or 256000 baud, depends on firmware) |
| RX | Input (the ESP32 drives it) | D26 | UART: the part receives data here. Connect to an ESP32 TX pin |
| OT2 | Output (the part drives it) | D27 | HIGH when a person is present (3.3 V) |
Suggested wiring for the 30-pin ESP32 DevKit, avoiding flash, input-only and strapping pins. BoardPilot checks it for you as you wire.
Sources
- Hi-Link HLK-LD2420 user manual, Supply 3.3 V; pins 3V3, GND, OT1 (UART TX), RX, OT2 (presence output)
Try it in 3D in BoardPilot
Learn the basics
Lesson: UART, I2C and SPI Lesson: GPIO: pins in and out UART (serial port) Baud rate GPIO
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Part data: CC BY 4.0, free to reuse with credit to BoardPilot.