I’m working on a research project and have a few hopefully quick questions about the RS&BOOM. For context: I’m putting together a sensor package for some field recording that will include an RS&BOOM. Specifically, it’s for characterising the noise coming from aircraft during landing and takeoff, including the infrasonic range. It’s part of a larger project that aims to simulate and predict the impact of aircraft overflight noise on the communities below for a new airport (the communities are, by what I’m sure is just complete coincidence, all lower-income areas).
Can we add and run our own code on the Raspberry Pi? Is the OS “locked down” in any way? My understanding is that the software comes loaded on the device, shipped as a docker image running on top of a standard Linux distribution. I wouldn’t expect anything to be locked down, but need to make certain.
At a rough estimate, what percentage of CPU time and memory does the software as-shipped consume under normal operation? My intention is to use the RS&BOOM’s Pi to also run the code for recording the other sensors in the package: a calibrated microphone, and a radio for grabbing aircraft status reports (ADS-B). Doing this avoids the complication of having a second Pi (including communication, power, syncing clocks, etc.). I don’t expect either of these sensors to consume much processing power or memory; it would just need to write an audio stream and fairly small text log to disk.
As a programmer with zero experience in acoustics: how low can the infrasound transducer get in frequency before you can’t rely on the output? Eyeballing the charts in the data sheet, it looks like you could make 0.1Hz work. The project lead basically gave me a request for “as low as possible” and mentioned 0.01Hz at one point, but I dunno if he’s getting that.
This is quite interesting, looking forward to the result you’ll get! Let’s cover one question at a time:
Yes, you can add and run your own code on the Raspberry Pi. The OS is not locked down. You’re correct that the Raspberry Shake software runs on Debian Linux with the core functionality distributed via Docker. You have full access to the underlying Linux system, so you can install additional software, run custom scripts, and integrate other sensors as needed for your project.
Under normal operation, the Raspberry Shake software is quite lightweight. We could say, as an estimate, that around a quarter of the resources are used on average. This leaves some headroom on the Raspberry Pi for additional tasks. Recording audio streams and logging ADS-B text data should be within the remaining capacity, especially since these are relatively low-overhead operations.
That said, on points 1) and 2), however, we recommend that only the Shake OS runs on the Pi computer itself, to provide maximum processing power to the tasks it has to perform in all situations. It will be a matter of experimenting with what you want to add and checking how much this additional software may affect Shake’s performance.
According to the technical specifications, the RS&BOOM’s infrasound sensor has:
-3dB points at 1 Hz to 44 Hz (with the default 1s mechanical filter)
-3dB points at 0.08 Hz to 44 Hz (with the optional 20s mechanical filter - available upon request only)
For your aircraft noise characterization project, the RS&BOOM should work well for infrasonic frequencies down to around 0.08-0.1 Hz (with the 20s filter), but it could be difficult to lower it even further to capture 0.01 Hz. You might want to discuss this limitation with your project lead.