The LD19 Sees 360°. Why It Cannot Replace a TFmini-S
Quick Answer
The LDROBOT LD19 is a 360-degree scanning LiDAR for two-dimensional maps, not a drop-in alternative to a forward-facing rangefinder. Give it regulated 5V power, connect its one-way TX line to a 3.3V-compatible UART receiver, ground PWM for internal speed control, then select the LD19 model and 230400 baud in its ROS2 driver.
The Same 12m Number Hides Two Different Sensors
Our catalogue lists both the LD Robot LD19 D500 and Benewake TFmini-S with a nominal 12m maximum. That shared number is where the similarity ends.
The LD19 spins a laser around the horizontal plane, producing angle, distance and intensity data for mapping and obstacle avoidance. Our current product record specifies a 360-degree scan, 6–13Hz rotation, 5000 ranging samples per second, 45g sensor mass and 54 × 46.29 × 35mm body. This is the sensor we would choose for a small indoor rover that needs a plan view of walls, furniture and doorways.
The TFmini-S is a fixed, single-point sensor: it measures along one narrow forward beam. Benewake specifies 5g, a 0.1–12m range on a 90% reflective target and an adjustable frame rate up to 1000Hz. For altitude, docking or “is there an obstacle directly ahead?”, we would take that simpler geometry and lower mass rather than fit a spinning scanner.
Wire the LD19 Before You Touch ROS2
The four LD19 connections are 5V, ground, TX and PWM. Its supply range is 4.5–5.5V; our listing gives 290mA operating current. TX is one-way data at 230400 baud, 8 data bits, one stop bit and no parity, so connect LD19 TX to the receiver pin on your USB-UART adaptor or single-board computer. There is no LD19 RX line to cross back.
If you are not commanding motor speed externally, ground PWM. Documentation revisions differ on whether an unconnected or high-impedance pin also selects internal control, but the development manual’s grounded-PWM method is unambiguous and defaults to roughly 10Hz. We would use a CP2102 USB-UART adaptor for a laptop or USB-connected Raspberry Pi and verify that the serial side accepts 3.3V logic.
The ROS2 Setup That Usually Gets Missed
LDROBOT’s current ROS2 repository includes an LD19 launch file with product_name set to LDLiDAR_LD19, port_baudrate set to 230400 and the default device at /dev/ttyUSB0. Change the port to the device that actually appears on your computer, build the workspace with colcon build, source install/setup.bash, then run ros2 launch ldlidar_stl_ros2 viewer_ld19.launch.py.
A successful driver launch is not yet a trustworthy map. Set the static transform to the sensor’s measured position on your chassis, confirm clockwise versus counter-clockwise scan direction, and mask angles blocked by the robot body. For aircraft that need motion estimation rather than a floor-plan scan, start with our optical-flow sensor guide. Browse the verified sensors collection by measurement job, not by headline range.
What We Would Actually Choose
Choose LD19 for two-dimensional SLAM and room-scale rover navigation. Choose TFmini-S for one fast distance channel where 5g matters. We would not buy either merely because “12m LiDAR” appears in the specification: scan geometry, interface and mounting decide whether the data is useful.
FAQ
Q: Can the LD19 connect directly to a Raspberry Pi?
A: Yes, through a suitable 3.3V UART input or a USB-UART adaptor. Provide regulated 5V power, share ground and never feed 5V into the Pi’s UART RX pin.
Q: Does the LD19 need a command to start scanning?
A: No. With power applied and PWM grounded, it uses internal motor control and transmits one-way UART data after the rotor stabilises.
Q: Is the LD19 suitable as a drone altimeter?
A: Not our first choice. A 45g horizontal scanner is built for planar mapping; a light single-point sensor is the cleaner fit for one downward distance measurement.