Electrical Schematics (Falcon) - norlab-ulaval/Norlab_wiki GitHub Wiki

Introduction

This page details the electronic design of Falcon, how things are powered and connected together.

Schematic

Below is the full electrical schematic of the drone's components in a simplified way. Specific parts are detailed in subsections below, and the original drawing is available here.

Kore Carrier Board

The Kore Carrier Board is at the center of the drone. It was chosen to simplify wiring as it includes strategically placed motor outputs, all the exposed flight controller ports, power measurements and 5/12 V DC outputs. The Cube Orange+ is screwed directly in the middle. Detailed documentation about this board is available here.

The connectors used for Cube ports are JST-GH, while the carrier board power ports are Molex Clik-Mate.

Electronic Speed Controllers

The ESC is an electronic circuit that controls and regulates the speed of a brushless DC motor. It acts as a middleman between the battery and the motor, taking signals from the flight controller to precisely adjust the motor's speed and direction. The image below shows a simplified illustration of the system.

On Falcon, the ESCs are tucked inside the four arms. Since there are two ESCs per arm and space is limited, we had to shift them and adjust the wire lengths accordingly. The image below shows the wiring of the ESCs to the motors in one arm.

  • Left: Flight controller connection. Red and black wires are for power and are soldered on battery-connected pads. The small white/black wires are for control signals, in this case PWM from the flight controller.
  • Right: Motor connection. The wires are soldered together and the order of the three phases is not important, as the ESC can be reversed in the firmware.

For ESC configuration, see the Encountered Issues page.

Doodle Labs Radio

The Doodle Labs Radio requires 5V/3A DC power to operate. Hence, we did not use the integrated DC/DC of the carrier board and added a separate LM2596, connected to the battery output of the carrier board, which includes a protection fuse. The three connectors of the picture below respectively correspond to:

  • Power input
  • Ethernet -> Jetson Nano
  • Serial -> Cube TELEM1 (as a backup link)

The full documentation of the device is available here.

Jetson Orin Nano

The Jetson Orin Nano is also powered for a separate DC/DC converter, as it requires 19V/2A to operate. As mentioned above, its Ethernet port is also connected to the Doodle Labs radio to communicate with the base station. Finally, it is linked to the flight controller through a telemetry UART connection (TELEM2).

⚠️ The UART on the Jetson was not strong enough to drive the RX pin of the Cube, hence we patched it with a small circuit, see Encountered Issues page for details.

The full documentation of the Jetson dev kit is available here.

Raspberry Pi Camera

The Raspberry Pi HQ Camera is directly powered by the Jetson's CSI connector. However, since the Jetson's CSI connector is 22-pin and the camera is 15-pin, we require an adaptor cable such as this one. Careful as there exist "Display Cables" which don't have the same pinout at all and will not work for the camera (example).

See Companion Computer page for more details about how to connect the camera to the Jetson.