It's All About the BUZZzzzZZzzzZzzzZZZzzz
First, Understand the Bee. Then Choose the Mic
Before selecting a microphone, we first needed to understand the acoustic “specifications” of the Western honey bee (Apis mellifera).
A colony is a remarkably complex acoustic environment. Worker activity produces the familiar hive hum, while specific signals—including worker piping and stop signals—occupy identifiable frequency ranges and patterns. Queens add another acoustic layer through piping and tooting, with fundamental frequencies and harmonics extending across a broader range. Research has documented A. mellifera stop signals around a few hundred hertz, for example, with other piping signals occupying overlapping ranges.
For Ocellus, this meant the microphone needed to reliably capture low-frequency bee sounds, roughly 150–1,200 Hz, while also providing enough bandwidth to preserve the harmonics and other acoustic information useful for machine listening. It also needed low noise, low power consumption, digital output, and—critically—a package small enough to fit inside the hive.
After reviewing the literature, consulting specialists in bee behavior and acoustics, and speaking with several microphone manufacturers, we selected the Knowles SPH0645LM4H I²S digital MEMS microphone for our prototype.
At only about 3.5 × 2.65 × 1 mm, it provided an omnidirectional response, 65 dB signal-to-noise ratio, low power consumption, and a frequency range comfortably encompassing the honey bee signals we wanted to study. Its digital I²S output also allowed the microphone to communicate directly with the processor without requiring a separate audio codec.
The microphone wasn't selected because it was designed for honey bees. It was selected because we first learned what honey bees required from a microphone.
I would put your Worker/Queen Honey Bee Acoustics infographic directly after the second paragraph. It becomes the centerpiece of this post—the visual representation of the bee's “specifications.”
Then you don't need another complicated graphic. The post naturally leads into Safe and Sound, where you show how that microphone was actually incorporated into the PCB.
One small correction to the infographic itself: “Queen — Tooting (mated queen)” is not right. Tooting is generally associated with an emerged/virgin queen, while “quacking” is associated with queens still confined within their cells. I would fix that before putting this infographic on the website.
