Bat Detector 1.6

The BAT Detector is an innovative device that requires a 384kHz USB microphone, providing users the opportunity to explore the intriguing world of bat acoustics through their iPhone or iPad. Users can either purchase a pre-assembled microphone available at shop.smithrobotics.co.uk or choose to assemble one themselves via resources found at PCBWay.

All European bats and many of the globe’s "microbats" utilize ultrasonic sounds for navigation, hunting, and communication that are beyond the range of human hearing. The BAT Detector effectively brings these otherwise inaudible sounds to the user's perception through two distinct methodologies.

Unattended Bat Detection

One significant feature of the BAT Detector is its implementation of heterodyne bat detection, a classical technique allowing the detection of bat sounds in real-time. Unlike most traditional heterodyne detectors which require manual tuning to identify various species, the BAT Detector autonomously locks onto the strongest bat signals available. The heterodyne process converts the detected ultrasonic bat sounds into recognizable percussive noises such as cracks, pops, and slaps. Specifically, for leaf-nosed bats like Horseshoe species, the resultant sounds may resemble unusual alien warbles. It is crucial to note that these synthesized sounds do not accurately reflect the bats' original calls; rather, they are modified representations that retain rhythm and distinctiveness, making them valuable for bat research and observation.

Enhanced Auditory Experience with 16x Time Expansion

Another noteworthy feature is the 16x Time Expansion, which transforms bat sounds into an audible range. Once a high-end function, this quasi real-time feature captures short segments of ultrasonic calls and plays them back at one-sixteenth of their original speed. The choice of 16x ensures that these audio outputs fall well within human hearing capacity, spanning from 1kHz to just below 7kHz. Additionally, this process retains harmonic relationships within the bat calls, creating a musically transposed experience—bat calls are presented four octaves lower while maintaining pitch accuracy. Users will likely find this slowed-down version remarkably melodic. When combined with heterodyning and accurate frequency display, species identification becomes notably more efficient and reliable.

High-Fidelity Full-Spectrum Recordings

When engaged in recording mode, the BAT Detector initiates a five-second full-spectrum recording at 384kHz each time it detects bat sounds—or what it interprets as such. It is essential to clarify that these recordings capture the true ultrasonic sounds produced by bats, rather than what is emitted through the device's speakers. Users will require specialized software for further analysis of these recordings post-exportation from their devices.

Versatile Demo Mode for Educational Purposes

The BAT Detector also features a Demo Mode designed for educational settings or environments devoid of bats. By activating this option within the settings app, users can listen to a curated collection of bat recordings sourced from Wiltshire, England. Additionally, users have the option to utilize their personal recordings by organizing them into a dedicated folder named 'Demo' in Files->Bat Detector—provided they meet specified criteria (5 seconds in length, 384kHz, mono, 16-bit). If unsure about compatibility, using Bat Detector for initial recording is recommended.