Ai-Thinker Rd-03H 24GHz Human Presence Radar Module
The Ai-Thinker Rd-03H is a compact 24GHz millimeter-wave radar module for human presence detection, motion detection, and slight-movement sensing. It uses ICLEGEND Micro's S1KM0000 radar SoC with a one-transmit, one-receive antenna design, making it suitable for embedded projects that need non-contact presence feedback in a slim DIP module format.
Unlike simple PIR sensing, 24GHz FMCW radar can detect motion and micro-motion within the configured sensing area. The official Rd-03H specification lists up to 8m wall-mounted sensing distance, ±60° coverage, UART configuration, automatic detection-threshold generation, and a 35 × 7mm module size for compact device integration.
For related OpenELAB radar options, compare the Ai-Thinker Rd-03 24G Millimeter Wave Radar V2 , Ai-Thinker Rd-03D 24G Radar , Ai-Thinker Rd-03E 24G Radar , and Ai-Thinker Rd-03L V2 24G Human Presence Sensor . For evaluation and configuration workflows, the Ai-Thinker Radar Debugging Board is a useful companion accessory.
Technical Specifications
| Parameter | Value |
|---|---|
| Brand | Ai-Thinker |
| Model | Rd-03H |
| OpenELAB SKU | AT-Rd-03H |
| Product Type | 24GHz human presence detection radar module |
| Radar SoC | ICLEGEND Micro S1KM0000 |
| Radar Technology | FMCW millimeter-wave radar |
| Frequency Range | 24GHz to 24.25GHz ISM band |
| Antenna | Onboard 1T1R antenna |
| Package | DIP-5 with standard 2.54mm pin header spacing |
| Module Size | 35.0 × 7.0mm, ±0.2mm |
| Maximum Sensing Distance | Up to 8m for wall mounting in the ±60° range, based on Ai-Thinker open-space testing |
| Ceiling Sensing Reference | At 3m mounting height, circular projection radius is listed as 5m typical |
| Detection Coverage | Up to ±60° detection angle |
| Supported Detection | Moving human body and slight human movement detection |
| Interface | UART |
| Default Baud Rate | 115200 bps |
| Pin Definition | VCC, GND, TX, RX, IO |
| Supply Voltage | 3.0V to 3.6V, 3.3V typical; verify delivered hardware version before using 5V |
| Recommended Supply Current | At least 200mA available from the power supply |
| Average Working Current | 50mA typical at 3.3V and 25°C |
| Operating Temperature | -40°C to 85°C |
| Storage Environment | -40°C to 125°C, less than 90%RH |
| Configuration Support | Sensing range, interval sensitivity, unattended delay time, and automatic threshold generation |
| Mounting Methods | Wall mounting and ceiling mounting are supported by the official specification |
Integration Notes & Installation Guidance
- Power Supply — Use a stable 3.3V supply for the default version and reserve at least 200mA current capacity.
- Ripple Control — Ai-Thinker recommends LDO power where possible; if DC-DC is used, keep output ripple low and reserve suitable capacitors.
- UART Setup — Use the module UART interface for configuration and data communication, with 115200 bps as the listed default serial rate.
- Antenna Clearance — Keep metal parts and high-frequency devices away from the antenna area to avoid degrading radar performance.
- Stable Mounting — Fix the module firmly; vibration or shaking of the radar itself can affect detection results.
- Backside Interference — Avoid moving objects behind the radar, or use shielding when the installation environment creates unwanted backlobe detection.
- Multi-Radar Layout — When multiple 24GHz radar modules are used nearby, avoid direct beam alignment and increase spacing where possible.
- Environment Check — Large reflectors, moving curtains, pets, fans, plants, and air outlets can affect the detection result and should be considered during commissioning.
- ESD Handling — Treat the module as an electrostatic-sensitive device and use proper ESD handling during installation.
Packing List
- 1 × Ai-Thinker Rd-03H 24GHz Human Presence Detection Radar Module
FAQ
Q: What is the main difference between Rd-03H and a PIR sensor?
A: Rd-03H uses 24GHz millimeter-wave radar and can detect motion and slight human movement in the configured sensing area, while PIR sensors mainly respond to infrared changes.
Q: What is the maximum detection distance?
A: The official specification lists up to 8m in wall-mounted open-space testing within the ±60° range. Actual results depend on mounting position, environment, reflectors, and target condition.
Q: What voltage should I use?
A: Use 3.3V for the default version. The specification notes version-dependent voltage support, so verify the delivered hardware before applying 5V.
Q: Which interface does the module use?
A: The module supports UART communication, and the default serial rate is listed as 115200 bps.
Q: Can it be ceiling mounted?
A: Yes. The specification supports ceiling mounting and gives a 3m mounting-height reference with a 5m typical circular projection radius.
Q: Why does the radar trigger when no person is present?
A: Moving curtains, fans, pets, plants near air outlets, large reflectors, vibration, or moving objects behind the radar can cause false detection and should be checked during installation.
Q: Does it need configuration?
A: For best results, configure the sensing range, interval sensitivity, and delay settings according to the final installation environment.