LightWare SF1X/SF02/LW20 Lidar

LightWare develops a range of light-weight, general purpose, laser altimeters ("Lidar") suitable for mounting on UAVs. These are useful for applications including terrain following, precision hovering (e.g. for photography), warning of regulatory height limits, anti-collision sensing etc.

Supported Models

PX4 supports the following LightWare Lidar rangefinders:

• SF02 (50 m)
• SF10/A (25 m)
• SF10/B (50 m)
• SF10/C (100m) (Discontinued)
• SF11/C (120 m)
• LW20 (100 m) - Waterproofed (IP67) with servo for sense-and-avoid applications

The lidars can be connected to I2C or serial ports, depending on their type (see below)

• Serial: SF02, SF10/a, SF10/b, SF10/c, SF11/c
• I2C: SF10/a, SF10/b, SF10/c, SF11/c, SF/LW20

I2C Setup

The following models can be connected to the I2C port: SF10/a, SF10/b, SF10/c, SF11/c, SF/LW20

Hardware

Connect the Lidar the autopilot I2C port as shown below (in this case, for the Pixhawk 1).

Some older revisions cannot be used with PX4. Specifically they may be miss-configured to have an I2C address equal to 0x55, which conflicts with rgbled module. On Linux systems you may be able to determine the address using i2cdetect. If the I2C address is equal to 0x66 the sensor can be used with PX4.

Parameter Setup

Set the SENS_EN_SF1XX parameter to match the rangefinder model and then reboot:

• 0: Disabled
• 1: SF10/a
• 2: SF10/b
• 3: SF10/c
• 4: SF11/c
• 5: SF/LW20

Serial Setup

Hardware

The lidar can be connected to any unused serial port (UART), e.g.: TELEM2, TELEM3, GPS2 etc.

Parameter Setup

Configure the serial port on which the lidar will run using SENS_SF0X_CFG. There is no need to set the baud rate for the port, as this is configured by the driver.

If the configuration parameter is not available in QGroundControl then you may need to add the driver to the firmware.

Then set the SENS_EN_SF0X parameter to match the rangefinder model and reboot:

• 0: Disabled
• 1: SF02
• 2: SF10/a
• 3: SF10/b
• 4: SF10/c
• 5: SF11/c

Further Information

• Modules Reference: Distance Sensor (Driver) : sf1xx (PX4 Dev Guide)