Laser Interface

Overview

Laser Interface

The Avionics Anonymous Laser Altimeter Interface is a tiny interface for several common laser rangefinders that allows connection to Pixhawk and other similar autopilots via UAVCAN - A nice robust interface, no sketchy long-distance I2C wiring and no hogged serial ports! These lasers are great for use as laser altimeters which help with nice auto landings. Comes fully assembled, ready to use!

Currently supported Lasers

At time of writing the following rangefinders are supported:

  • Lightware SF02

  • Lightware SF10/a

  • Lightware SF10/b

  • Lightware SF10/c

  • Lightware SF11/b

  • Lightware SF11/c

  • Lightware SF(LW)20/b

  • Lightware SF(LW)20/c

  • Lightware SF30/D

Coming soon:

  • Lidar Lite

  • Others - contact us with your needs!

What makes it special?

  • Robust UAVCAN interface is compatible with most Pixhawks and similar autopilots and makes it safe to install your laser far away from the autopilot, wherever is convenient!

  • Onboard power filtering for connected laser

  • Mount with screws through mounting ears or snip them off and foam tape it straight to your laser

  • Update firmware via CAN interface

Specifications

  • Weight: 3.2 grams

  • Size: 1.25in x 0.75in x 0.25in

  • Power: 4.0V to 5.5V, XXmA

Required Accessories

  • CAN Harness - connects between the autopilot and a CAN node and between each CAN node on the bus

  • CAN Terminator - connects to the last device on the CAN bus

Where to Buy

User Guide

Wiring

The rangefinder (laser) is connected to the AvAnon Laser Interface board, which is connected to one of the CAN ports on your autopilot. The wiring is per the pinout below, or the necessary cables can be purchased to connect to your system right out of the box:

  • CAN Harness - connects between the autopilot and a CAN node and between each CAN node on the bus

  • CAN Terminator - connects to the last device on the CAN bus

The interface board provides a filtered power output for the laser, but does not provide its own regulation. Therefore, the laser must be compatible with whatever voltage is supplied to the Laser Interface.

Pinouts

CAN Connector

Pin

Name

Description

1

POWER_IN

Power Supply. 4.0-5.5V supported, but must also be compatible with connected laser.

2

CAN_H

CAN high

3

CAN_L

CAN low

4

GND

Signal/power ground.

Laser Connector

Pin

Name

Description

1

POWER_OUT

Filtered power at the supply voltage.

2

TX/SCL

TX for serial mode, Clock for I2C mode

3

RX/SDA

RX for serial mode, Data for I2C mode

4

GND

Signal/power ground.

Connection to Lightware SF0x/SF1x/SF30 Lasers
Connection to Lightware LW20

Configuration

Autopilot Configuration

PX4

Several autopilot parameters must be set using QGC or similar:

  • UAVCAN must be enabled by setting UAVCAN_ENABLE non zero. Set this to 1 for basic functionality or 2 to allow the device's UAVCAN parameters to be accessed via QGC.

  • The minimum and maximum valid range for the laser must be set in the parameters UAVCAN_RNG_MIN and UAVCAN_RNG_MAX. These should be set according to the rangefinder manufacturer's datasheet.

Rangefinder Configuration

Certain parameters must be configured in your rangefinder per the manufacturer's guidance

Rangefinder Model

Notes

Lightware SF02

Must be set to 115200 baud

Lightware SF10/a

Must be set to 115200 baud

Lightware SF10/b

Must be set to 115200 baud

Lightware SF10/c

Must be set to 115200 baud

Lightware SF11/c

Must be set to 115200 baud

Lightware SF11/b

Must be set to 115200 baud

Lightware SF(LW)20/b

Must be set to 115200 baud. Returns default distance.

Lightware SF11/b

Must be set to 115200 baud. Returns default distance.

Lightware SF30/D

Must be set to 115200 baud. Returns default distance.

Node Configuration

The Laser Interface node has a number of parameters accessible via the UAVCAN interface. These may be set following the steps outlined here

Parameters

Parameter Name

Description

Default Value

Allowable Values

node_id

Node ID for this device

103

1-125

rangefinder_hw

Rangefinder type specifier - see list below

5 (or as ordered)

1-10 (see below)

first_return

Use "first" or "last" return range, if supported by rangefinder

0

0 = last return, 1 = first return

Rangefinder Hardware Options

Rangefinder Model

rangefinder_hw Value

Wiring Type

Lightware SF02

1

Serial

Lightware SF10/a

2

Serial

Lightware SF10/b

3

Serial

Lightware SF10/c

4

Serial

Lightware SF11/c

5

Serial

Lightware SF11/b

6

Serial

Lightware SF(LW)20/b

7

Serial

Lightware SF11/b

8

Serial

Lightware SF30/D

10

Serial

Firmware

Release Notes

v1.2

  • Improve SF0X timeout recovery

v1.0

  • Initial Release