In a recent blog post I talked about finding some Pine A64 single board computers in a box and how this was the catalyst for my High Altitude Balloon (HAB) Telemetry experiments. In this post I continue describing the initial experiment with the Pine A64’s to test if they were capable of running the Project Horus software.
Pine A64 Operating System
So the choice of Linux operating system for the Pine A64 2GB SBC had grown substantially since the first time I experimented with these boards after the initial KickStarter campaign. After some trials and tribulations I settled on the DietPi distribution. This included a relatively modern kernel and a nifty installation and package management system, with a Debian based back-end. It is also highly optimised to run on small SBC’s, it only runs the bare minimum processes required and has logging to RAM enabled rather than to SDCard.
Setting up DietPi on this board was no different to any other ARM based SBC. Burning the image to SDCard, booting the device with a USB keyboard and monitor was straight forward. One nice part of DietPi is the setup and configuration is done within a Ncurses menu, similar to the raspberry Pi. So tuning and setting up the board just requires poking around these menus and configuring the hardware you want to use. Once done I found I was using just under 1GB of the 32GB SDCard I’d inserted, which included all of the GCC build tools I needed to compile programs from source. I was impressed.
Tracking Software and SDR’s
The first HAB tracking software I wanted to try was the Horus 4FSK binary telemetry. The Project Horus software team have done a great job documenting how to build and run this software in their GitHub wiki. The Horus guide recommends the RTL-SDR if you intend to run a Headless Raspberry Pi and I had a draw full of them left over from various projects. If you’re not familiar with these you can find them here, please be aware of fakes on eBay the frequency stability of these fakes typically results in tears. I’ve used the RTL-SDR V3 as pictured above.
It didn’t take me more than an hour to get this software running which included building the RTL-SDR software from source, editing the startup scripts and testing that dual 4FSK de-modulators were running. I was lucky to have a RS41 radio sonde that had been modified to generate this data mode, more detail can be found here. I was thankful that the DietPi distribution is very similar to the current Raspberry Pi platform, so all commands simply worked, those that didn’t required nothing more than installing the missing package or dependency and trying again.
Running both Horus 4FSK binary telemetry decoders on DietPi saw the system peak load get no higher than 0.6 (~15%), considering that the Pine A64 is a quad core 1.2GHz ARM, this is very lightly loaded. There is definitely more scope to add further functionality on this SBC.
So having cloned the SDCard just prior to installing the Horus 4FSK binary telemetry software, I then started again a fresh on the second Pine A64 and installed the Wenet software. Again the installation documentation for Wenet is excellent and I chose to go the Docker path rather than build from source. This time however the system peak load, rose to 1.6 and peaked no higher than 2.5 (~63%), meaning a single Docker Wenet decoder is about as much as I was confident loading this system with using a RTL-SDR.
Next Steps
So based on the above experiments, it was clear the Pine A64’s that spent the better part of 5 or more years languishing in my shed were more than capable of tracking HAB balloons and would finally be pressed into service.
As hinted within the Project Horus documentation there is more than just software required to track High Altitude Balloons. It was time to continue digging through that shed to find more treasures for this new project.
That however will need to wait for the next post, more to follow.