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What frequency are these set to? Why?The frequency is set to the 902-928 MHz band because this is a license-free ISM (Industrial, Scientific, and Medical) frequency band, which is applicable in the US. The 900 MHz band provides a good trade-off between antenna size and range.Why do the antennas need to be connected before powering?The antennas must be connected before powering because transmitting without a load can damage the radio’s power amplifier.What is special about the USB Serial plug? It is an FTDI USB-to-TTL cable with 3.3 V logic, specifically designed for the modem’s interface. It can supply 5V power for programming.What is pin one on the RFD900 USB Serial Connector, and what color wire connects to it? Please attach a photo before plugging it into your computer's USB. Pin 1 on the RFD900 USB Serial connector corresponds to the black wire of the FTDI cable. You must align the black wire to pin 1 before plugging in the USB to prevent mis-wiring.
What is BAUD?Baud is the number of symbols transmitted per second. Concerning the RFD900, the default serial baud rate is 57,000; both connected devices must match this rate in order to communicate.
The file provided by Windracers has a .apj file extension. What does this mean and why?It is pre-built binaries that include the Ardupilot code, compiled for the specific hardware. Allowing for easier loading via the ground-station tools for autopilots, support for customization, and providing a more flexible “container” format for boards with ardupilot-compatible bootloaders.What is Mission Planner? What are the alternatives to Mission Planner?Mission Planner is a ground control station (GCS) software application for ArduPilot-based autopilots. QGroundControl (cross-platform: Windows, Mac, Linux, mobile) – supports MAVLink, ArduPilot, and PX4. APM Planner 2, another GCS for ArduPilot, supports macOS / Linux / Windows. MAVProxy, a command-line-based GCS for advanced users.Do you expect the Windracers flight controller firmware to work with Mission Planner?The firmware they provided uses a .apj extension, which is the ArduPilot JSON firmware format. This suggests that it is an ArduPilot-compatible firmware build. Given that Mission Planner supports loading .apj files (though some versions had quirks) and is the standard GCS for ArduPilot boards. This means you can use Mission Planner with that firmware provided.How much memory does the Blue Cube have?Flash memory 2 MB, RAM 1 MB
Lab 08 - Believer Comms and Firmware
Introduction:
In this lab, my group worked on setting up and testing the RFD900x-US Telemetry Modem, as well as installing the Windracers Standard firmware on the ArduPilot Flight Controller and Blue Cube Autopilot system.
Pre-Lab Specific Questions & Answers
Activity 1: Set up RFD900x
Specification Questions:
Activity 2: Installing Firmware
Specification Questions:
Process:
Activity 1: Set up RFD900x
First, we downloaded the RFDTools software onto my computer to set up the modem to the required specifications. Then we connected the ground unit to my pc and modified the settings to the given specifications (Serial Speed (BAUD) = 115, NETID = 100). We had some trouble with changing the settings, as none of us in my group had done anything like this before, so navigating the RFDTools software was a little difficult for us. Connecting to the settings, we didn't know that you had to “load” settings. And, once the settings were saved, we had to disconnect it, but we did not know.
Second, we tested the communication of the modems by using another downloaded software named PuTTY. We connected two separate modified modems to two separate computers, both running the software. To connect the modems, we had to find out the COM port used and input it into the software, along with the BAUD value we used (115000). Once those were input, a datalink was established, and we were able to communicate between devices. My group members had a little trouble getting it to work on their end, but it worked the first try for me.
Activity 2: Installing Firmware
On one of the provided PCs, we accessed the pre-downloaded Mission Planner software to communicate with the Flight Controller. We followed the to install the firmware, which in our case was just as easy as selecting the provided .apj file off of our TA’s thumbdrive and setting the BAUD value to 115200 (same as the telemetry modem). On the original computer we tried to do this on, when we would select the .apj, the software kept crashing. So we swapped computers and continued without issue.
To test the installation, we used another program called Ground Control. We simply had to connect the flight controller to the program (via COM port and BAUD of 115200), and it automatically connected and was displayed in the flight planning menu.
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