Attributes

Brand	-
Category	Robotics / STEM Teaching Tools / Sensors
Origin	-
Operating Frequency	24 GHz Millimeter Wave
Model Number	LD303
Detection Range	0.5m to 15m (Adjustable)
Interface Type	TTL Serial Output (UART)
Supply Voltage	3.3V - 5V DC
Beam Angle	Horizontal 90°, Vertical 60°
Response Time	< 100ms
Operating Temperature	-20°C to +70°C
Dimensions	25mm x 25mm x 4mm
Application Scenario	Smart Home, Presence Detection, Automation

6 reviews

Anonymous

Mar 20, 2026

Rating: 3/5

Documentation could be better

The hardware itself seems robust and the range is accurate. My only complaint is that the protocol documentation for the TTL output was a bit sparse, requiring some trial and error to get the data stream right.

Anonymous

Mar 19, 2026

Rating: 4/5

Good value but needs calibration

The sensor detects motion well even through thin plastic covers. However, you need to spend some time calibrating the sensitivity via the serial commands to avoid false positives. Overall, a solid choice for the price.

Anonymous

Mar 16, 2026

Rating: 4/5

Compact and reliable

Small form factor makes it easy to hide in enclosures. The 24GHz frequency provides good resolution. Deducting one star because the connector pins are a bit fragile, so handle with care during soldering.

Anonymous

Mar 12, 2026

Rating: 5/5

Perfect for bathroom automation

Installed this to control exhaust fans. It detects breathing and slight movements so the light doesn't turn off while someone is sitting still. Works perfectly behind a decorative panel.

Anonymous

Mar 12, 2026

Rating: 5/5

Superior to standard PIR

Unlike traditional PIR sensors that only detect heat movement, this millimeter wave radar can detect static presence. This was exactly what I needed for my office occupancy counter. Highly recommended.

Anonymous

Mar 11, 2026

Rating: 5/5

Excellent precision for DIY projects

I integrated this LD303 module into a smart lighting system and it works flawlessly. The serial output is easy to parse with an Arduino, and the detection range is very consistent compared to PIR sensors.

5 FAQ

Q: Can this sensor detect a person sitting completely still?

A: Yes, unlike PIR sensors, the LD303 millimeter wave radar can detect micro-movements such as breathing, allowing it to sense static presence effectively.

Q: What is the baud rate for the TTL serial output?

A: The default baud rate is typically 115200 bps, but it can be configured via specific serial commands found in the detailed technical manual.

Q: Does this work through a plastic enclosure?

A: Yes, 24GHz millimeter waves can penetrate non-metallic materials like plastic, wood, and glass, so it works well inside hidden enclosures.

Q: What is the maximum detection distance?

A: The maximum effective detection range is approximately 15 meters for large moving objects, though this can vary based on environmental factors and configuration settings.

Q: Is there a library available for ESP32?

A: While we do not provide an official library, many users have created open-source libraries for ESP32 and Arduino that parse the LD303 data stream. Please check GitHub for community contributions.

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