Cleanflight on the Skyline 32

The Skyline 32 is the flight controller; it has an onboard accelerometer and gyroscope, and sends commands to the ESCs. We compile the firmware (called CleanFlight) with an option that allows us to control the Skyline via USB. In this part, you will mount and configure the Skyline 32, install new firmware on it, and power up the motors!

Mounting the Flight Controller

Plug the voltage monitoring cable (now soldered to your BEC) and the 6-channel PWM cable into your skyline

Use double-sided foam tape to mount the skyline to the front of your drone. The USB port should be facing forward, so you have access to it.

It is very important that the flight controller is perfectly aligned with your drone’s frame. Any missalignments will mean that the sensors are getting incorrect (coupled axes) information about the acceleration. Make sure the edge of the flight controller is parallel with the edge of the frame.

Carefully plug your 6” USB cable into the USB port of the skyline. These little surface-mount USB micro ports are very prone to failure, so to minimize the likelyhood of ripping off the port or breaking a connection cover the USB connector thoroughly with hot glue. Yes, you will not be able to remove the USB cable. This is intentional.

Compiling Firmware For Skyline32

Download the pre-compiled hex.

You can also recompile the firmware. To do this, download the firmware source code at https://github.com/cleanflight/cleanflight and compile with

make arm_sdk_install

make NAZE OPTIONS=USE_MSP_UART

Flashing Fimware

1. Plug the skyline into the computer via USB. If your skyline is already on a drone, do not connect the battery.
   
2. Open cleanflight configurator and go to the "Firmware Flasher" tab. This tab is before you connect to the base station.
   
3. Click "Load Firmware [local]" and load your custom firmware file.
   
4. Click the "Flash Firmware" button to flash the flight controller.
   
5. If this is a success, the bar at the bottom will say "Programming: SUCCESSFUL" and you are ready to move to the next step.
   

Configuration Options

You will configure the flight controller based on our drone’s specific geometry and hardware.

1. Plug in Skyline and click "Connect"
   
2. Go to "Ports" tab and make sure SerialRX for UART2 is disabled and click "Save and Reboot." UART2 is a pin on the flight controller, and we want to make sure it only uses the USB.
   
3. Go to "Configuration" tab
   1. Flip the yaw by 180 degrees and click "Save and Reboot." This is because we mount the flight controller the opposite direction in order to leave the USB port free to plug into the Rasberry Pi.
      
   2. Also change the receiver to "MSP RX input" and click "Save and Reboot." By default it is configured to receive data from an RC receiver, but we want it to take commands over MSP.
      
   3. Set the Minimum Throttle to 1100.
   
   
4. Go to the "Receiver" tab and change the input map to "AERT1234" and click "Save." The input map is the order (Aileron, Elevator, Rudder, Throttle, and then auxiliary channels 1-4.) You have to type it into the Channel Map box; it will not be in one of the pulldowns. Click save.
   
5. We need tell it to be in Angle mode for the entire range (and not acrobatic mode). Go to the "Modes" tab
   1. Under "Angle", click "Add Range."
      
   2. Drag the sliders so that the range spans from 900 to 2100. (The entire range.)
      
   3. Click "Save."
      
   
   
6. We need to change the PID parameters to ones that work better on our drone. Go to the "PID Tuning" tab.
   1. Change the "ROLL" and "PITCH" PID terms to match the image. Roll should be (Proportional: 60, Integral: 40, Derivative: 50, RC Rate: 1.00, Super Rate: 0.00, Max Vel: 200). Pitch should be (Proportional: 60, Integral: 40, Derivative: 50, RC Rate: curly bracket, Super Rate: 0.00, Max Vel: 200)
      
   2. Change the "Angle Limit" to 50.
      
   3. Click "Save."
      
   
   

Plug in the motors

The numbers corresponding to each motor are as shown. Recall that the camera is in the back of the frame and the flight controller is in the front.

The yellow cable coming out of the skyline has 6 numbered connectors. Plug each motor into the corresponding connector (1-4) according to the above numbering scheme. The connectors shouldn’t be too easy to plug in backwards, but make sure the yellow wire from the motor goes to the yellow wire in the connector from the skyline.

Test the motors

This is the first time you will be firing up your drone! At this point, make sure there is nothing that could be potentially causing a short on your PDB. Take a battery and plug it into the XT60 connector. If you did everything right, lights should come on and the motors beep. If this doesn’t happen, unplug the battery immediately! It is likely the case that something is backwards or shorting, and you could be causing damage by applying a voltage.

Now plug in the Skyline to your computer via USB and connect to the cleanflight configurator.

1. Go to the Motors tab in Cleanflight. Make sure the props are off!
2. Read the safety notice and check the box that says “I understand the risks, propellers are removed - Enable motor control.”
3. Slowly power up each motor. Verify first that the correct motor spins and second that it spins in the correct direction using the diagram below.
4. If the motor does not spin, verify the connections, make sure there are no shorts and that it has power.
5. If the motor spins in the wrong direction, make a note of which motor it is. You will be able to flip the directions of motors that are spinning the wrong way in the next section.