Garmin LIDAR-Lite V3 Software&Document Download
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PULSEDLIGHT LIDAR-Lite V2 Download
If you have a LIDAR-Lite that has a manufacture date label prior to February 2015 there are I2C interface communications issues that will cause unreliable operation of the sensor with Pixhawk and will cause your vehicle to crash. When using these versions of LIDAR-Lite please use the PWM alternative listed below for best results.
The cable is configured with a 6-position Molex CLIK Mate connector on one end and tinned leads on the opposite end. You will need to solder the tinned ends to a modified DF13 4-pin I2C cable as shown below.
The power to the rangefinder should be supplied from a separate external BEC as shown in the diagram below.
The low pass filter shown in the diagram is required for first generation hardware (for hardware with manufacture dates prior to February 2015) - a schematic and PCB design are provided here. These should not be required in later versions of the LIDAR Lite (at which point the diagram will change as shown below:
It is important to ensure that the ground from the BEC is connected to the ground on the servo rail.
As of the 3.3.x release of Plane and Copter you can connect your Lidar via PWM as an alternative to I2C. This works around a number of bugs in the I2C interface for the Lidar. The bugs include generating spurious pulses on the I2C bus and lockups of the Lidar in flight.
To connect via PWM you need to connect 4 pins on the Lidar to the PWM rail of the Pixhawk. The connections are as follows:
|LIDAR-Lite Pin||Pixhawk Pin|
|J1||CH6 Out V+|
|J2||CH6 Out Signal (internal pin 55)|
|J3||CH5 Out Signal (internal pin 54)|
|J6||Ch6 Out Ground|
You need a resistor between J3 and ground. The exact value of the resistor isn’t critical, somewhere between 200 Ohm and 1kOhm will do. Testing for the development of the driver was done with a 470 Ohm resistor. The resistor is what tells the Lidar to start taking a reading, so connecting a resistor between pin 3 and ground tells the Lidar to go into continuous acquisition mode.
Here’s a picture of the necessary cable, with the resistor shown before being covered by heat-shrink tubing:
You then need the following parameters set to enable the PWM driver:
The use of pin 55 as the stop pin is just a suggestion, not a requirement. It connects to the enable pin on the Lidar, and allows the driver to reset the Lidar if it stops providing readings.
The use of pin 54 for the PWM signal is required, and only FMU AUX5 (pin 54) can be used due to the internal timer routing of the Pixhawk.
Note: when using LIDAR-Lite in PWM mode please keep the following in mind:
When using the PWM driver you can optionally set RNGFND_PWRRNG to a terrain height in meters above which the Lidar will be disabled to save power. When the terrain data indicates that the vehicle is above that height the RNGFND_STOP_PIN will be used to disable the Lidar. This saves around 100mA of current.
Your GCS must provide terrain data for this to work.
we would free provide the accessories package to use LIDAR Lite V3. The accessories can let LIDAR Lite to work with pixhawk or Arduino board.