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Lab 09 - Believer Avionics & Lab 10 - Parameters and Build Guide
Summary
This lab is focused on connecting the CubePilot flight controller to the Ground Control Station (GCS), configuring telemetry settings, adding the MS4525DO airspeed sensor and Here 3+ GPS and adjusting the other software parameters.
GCS
We used the AIDA PC to connect and configure the Cubepilot flight controller with a USB cable, and we moved the flight controller around manually to see if the flight controller was connected and outputting data correctly. Once we verified that the flight controller was working, we then used the telemetry modules we configured beforehand as a wireless link between GCS and the flight controller. It connected without problem, and we are successfully able to modify the SERIALX parameters.
SERIALX Parameters
Name
Original
Modified
Notes
SERIAL1_BAUD
115,200
115
Open
SERIAL1_PROTOCOL
MAVLink1
MAVLink
Open
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Air Speed Sensor
Connecting the air speed sensor was a simple process - we just connected it to the TELEM1 port and then modified the parameters to the recommended values. After successfully saving those changes, we were able to see our airspeed indication change as we blew air into the tube connected to the sensor.
ARSPDX Parameters
Name
Original
Modified
Notes
ARSPD1_TYPE
None
I2CMS4525D0
Open
ARSPD1_ADDR
40
0x28H
Open
ARSPD1_BUS
Bus1(external)
Bus0(internal)
Open
ARSPD1_TUBE_ORDR
either port
Port1
Open
ARSPD1_USE
Use
Use
Open
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GPS
Setting up the GPS was a similarly simple process - we plugged the 2 leads into the CAN1 and CAN2 ports, then flashed ArduPlane on the Cube in order to set up the GPS unit. We took the GPS outside and saw that it connected to satellites correctly - and the GCS updated to our location.
CAN Parameters
Name
Original
Modified
Notes
CAN_P1_DRIVER
Disabled
1
Open
CAN_P1_BITRATE
1000000
1000000
Open
CAN_D1_PROTOCOL
UAVCAN
DRONECAN
Open
CAN_D2_PROTOCOL
UAVCAN
DRONECAN
Open
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GPSX Parameters
Name
Original
Modified
Notes
GPS1_TYPE
AUTO
UAVCAN
Open
GPS1_ADDR
0
20
Open
GPS1_DELAY
150ms
100
Open
GPS1_POS_X
0
0
Open
GPS1_POS_Y
0
0
Open
GPS1_POS_Z
0
0
Open
GPS1_USE
UseForNavigation
UseForNavigation
Open
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Reflection
This lab was the first one where I was really able to see the way the Believer is laid out - although I have some experience with fixed-wings, the majority of my experience is with quad-type or experimental aircraft, and it was helpful to start seeing a “system” come together. It was also reassuring to see that the parts of the aircraft we’d been working on thus far did function as part of a whole.
Lab 10 Segment
Overview:
This lab was a continuation of Lab 9 - connecting to any aircraft requires two things. A transmitter and a receiver. On our aircraft we’re using the controller as a User Interface for a third-party transmitter rather than using the built-in transmitter. We’re using a “backpack” module called the TBS Tracer, which uses a protocol called CRSF - known for its superior penetration and distance capabilities over most standard protocols.
Copy of Parameters Version Control
Date
FCU Version
File
Notes
11/11/2025
1.31.3
Open
Open
Open
Open
Open
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Receiver Setup
Andrew and I each soldered header pins to the 3 Nano RX boards, updated the Transmitter to use the TBS tracer “backpack” module, and then bound the transmitter and receiver - verifying that they bound using the GCS software. Although the transmitter and receiver bound, the controller needed to be updated to be properly set up - we did that with a provided zip file, and the DATX with the tracer was able to communicate with the receiver. We did need to alter the Cube’s software as it wasn’t set up properly - we flashed the Cube with Version 1.31, but the version and parameters files had some sort of discrepancy, so that caused and error - we were given a new file that was supposed to facilitate these changes; however, we ran into a multitude of issues, which were ultimately resolved by using a different path to upload the file. At this point, we were able to test if everything still worked, and everything but the GPS did.
We fixed the GPS issue by flashing a new (different/updated) firmware. With the different firmware, the GPS parameters were changed, and then we reinstalled the Windracers firmware. I believe our group was the first to receive the updated firmware, as Professor Rose used a Cube running Ardupilot to tweak parameters and then test them in our system running Windracers' firmware. This process was relatively lengthy, stretching from the tail end of lab 10 to the beginning/middle of lab 11. We were able to get GPS signal, however, and verified this by placing the GPS module up against the window.
Note: Revised after GPS issues were resolved
| Connector | Connector Type |
|-----------|----------------------------------|
| GPS1 | JST-GH 1.25 mm (6-pin) |
| GPS2 | JST-GH 1.25 mm (6-pin) |
| TELEM1 | JST-GH 1.25 mm (6-pin) |
| TELEM2 | JST-GH 1.25 mm (6-pin) |
| I2C2 | JST-GH 1.25 mm (4-pin) |
| CAN1 | JST-GH 1.25 mm (4-pin) |
| CAN2 | JST-GH 1.25 mm (4-pin) |
| POWER1 | Molex CLIK-Mate 2mm (6-pin) |
| POWER2 | Molex CLIK-Mate 2mm (6-pin) |
| DSM | JST-GH 1.25 mm (3-pin) |
| POWER | JST-GH 1.25 mm (6-pin) |
| ADC | JST-GH 1.25 mm (6-pin) |
| DST | JST-GH 1.25 mm (15-pin) |
| ETH | TE Multi-purp plug (8P) |
Reflection
This lab was relatively straightforward aside from the aforementioned firmware/GPS issues - similarly to the last lab, I feel as though I’m starting to understand how the Believer system operates, as well as its advantages and disadvantages as a closed system. Being in a group was crucial for this lab, as I feel that individually all of us would’ve struggled significantly more than we did, given the unfamiliar nature of both Windracers Ground Control as well as their “sealed”/closed-off approach to flight controller firmware. If this had been ArduPilot, the fix likely would’ve been much faster and perhaps more relevant to our issues, easy to upload. Ultimately, it seems as though this lab is a good look into semi-closed source software and likely how many of the platforms i’ll be working with will be operated in the future.
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