Overview Note: this code is for experimental use only and constantly evolving!
Link to videos: https://youtu.be/co4E9P2Q5RQ
Requirements:
- Lidar Lightware SF/LW20 with serial connection
- Servo to control the scanning
- Arduino Mega
- NEW: Support for Arduino MicroPro boards
- USB cable to connect the Arduino to the breakout board
- Solo accessory bay breakout board
- 3DR Solo running Arducopter 3.5 or Arducopter 3.6 (lower versions are not supported)
- Latest Solex version for speech output
Prerequisites:
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Arduino:
- install the libraries for the lightware SF20 https://github.com/LightWare-Optoelectronics/LW20-Api
- deploy the Arduino sketch with the latest Arduino IDE
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Solo:
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Bridge the 3DRID pin on the breakout board to GND to set the Solo IMX as USB host and then connect the Arduino to the USB connector on the breakout board.
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You must have PyMata version 2.1 installed on Solo. Newer versions than 2.1 do not properly install on Solo. To download PyMata, go here: https://github.com/MrYsLab/pymata-aio
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Then install the buttonmanager.py and shotmanager.py files in the Solo /usr/bin directory using a SSH client
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The code works on all Solo firmware versions, however the LED visualization only works in Arducopter 3.5 and higher or with the special firmware of Hugh Eaves (thank you!) https://github.com/hugheaves/solo-led-control
Note: the code is not yet compatible with OpenSolo shotmanager!
Functionality: The code is constantly evolving. Current features include:
- 3 sector scanning for obstacles for objects within a 6 meter range ahead of Solo.
- scan is enabled by log-button press on the controller paddle. A short button press toggles the GoPro on/off as before.
- Scanning on/off is indicated by a text and voice prompt in Solex.
- the LEDs indicate the detection of an obstacle by flashing in purple color (Left LED: obstacle to the left; right LED: obstacle to the right; both front LEDs: obstacle in center)
- If a front collision is detected, Solo goes into BRAKE mode in all flight modes except LAND or RTL. It automatically switches back to Loiter (FLY) once Solo successfully stopped.
- Obstacle avoidance keeps track of the forward pitch angle along with Solo altitude. As soon as the pitch angle for the current altitude would cause the lidar beam to hit ground, obstace avoidance is temporarily disabled. Both front LEDs flash in yellow to indicate that status.
- NEW: downward-facing Rangefinder support to increase precision at low altitudes
- Text and speech output in Solex, for obstacles in the center of the flight path also the approximate distance to the obstacle is reported
Known limitations:
- no support for OpenSolo yet
- Works reliably only under clear weather conditions. In rain, snow and fog, the SF20 reports randomly false readings.
Feedback, issue reports and suggestions always welcome!