COMET - Cost-efficient Open-Source Multicopter for Embedded-Systems Teaching

Documentation Index

Welcome to the COMET documentation! This documentation will guide you through the processes of preparing, printing, assembling, setting up the electronics, configuring, and safely operating the drone.

Quick Links:

• Bill of Materials: docs/bill_of_materials.ods
• Printing guide: docs/printing.md
• Build manual: docs/build.md
• FCU and ESC configuration: docs/config.md
• Safety instructions: docs/safety.md

Software

The following is a list of the software used to create, 3D print, and operate COMET:

• FreeCAD 1.1.3
• Python 3.12.3
• PrusaSlicer 2.9.4
• INAV Configurator 8.0.1

Docker Environment Setup

For convenience, all software tools are contained in a Docker-based containerized environment. To set up the respective Docker image, use the following command in the root folder of this repository. All files related to this setup can be found in the docker folder.

. setup.sh

After this command, the update_project.sh script can be used in the repository’s root directory to update all project files according to the printing guide in docs/printing.md.

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Tools

The following is a list of the tools needed to build COMET:

• length ruler (from the 3D-printed frame parts)
• side cutter
• nose plier
• soldering iron, solder, and flux
• 1.5mm allen key
• 2.5mm allen key
• 5.5mm open-jaw wrench
• tweezers
• zip ties (different sizes)
• shrinking tube (different sizes)
• (optional) cable striper
• (optional) threaded inserts melting aid set

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Quick Start

These steps will guide you through the process of building your very own COMET drone.

1) Get the files

• Download one of the release ZIPs
• OR clone the repository:

  git clone https://github.com/uastw-embsys/comet.git
  

2) Order the non-printable parts

• Refer to the “bill of materials” sheet in docs/bill_of_materials.ods. It contains a detailed list of parts grouped by subassemblies from the build manual.
• Use the “order list” sheet for recommended parts, including filament spools for multiple drones. Don’t order filament spools if they’re already available.

3) 3D print the frame

• Make sure the 3D printer is properly calibrated (e.g., elephant footing and over- or under-extrusion).
• Print the gauge with the frame part filament and update parts based on clearances.
• 3D print the frame and color-coded parts:
  • Use 3MF projects in mechanical/prints/ that match your slicer and 3D printer
  • OR set up your own slicer project and use the provided projects as a reference.
• Install heat-set inserts where specified.
• For more detailed instructions, refer to the printing guide in docs/printing.md.

4) Assemble COMET

• Begin by assembling the individual COMET subassemblies.
• Assemble all subassemblies and finish the wiring.
• Perform final checks to ensure that the build is correct.
• Enjoy your self-built drone!
• For more detailed instructions, refer to the build manual in docs/build.md.

5) Flash and configure the FCU and ESCs

• Flash the official INAV 8.0.1 to the FCU, then apply the settings through the INAV CLI.
• Calibrate the accelerometer, magnetometer, and radio.
• Use the ESC Configurator to flash the Bluejay firmware onto the ESCs and apply the parameters.
• Verify the failsafes, motor order, and spin directions.
• For more detailed instructions, refer to the FCU and ESC configuration in docs/config.md.

6) First test flight!

• Perform all checks according to the safety instructions found in the docs/safety.md file.
• Share your experience and first flight with us!

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