Automated Delayed Noise Replayer

I need a self-contained system that can sit outdoors, listen specifically for my neighbours’ voices or shouting, and—only when they hit 55 dB or above—capture the sound, hold it for five seconds, then feed it wirelessly to an off-the-shelf Bluetooth karaoke speaker at the exact same loudness. Anything softer than that threshold is ignored; the rig must stay on, monitor continuously, and handle the entire record / delay / playback loop without my intervention.

I’m open to your choice of microphone, processor (Raspberry Pi, ESP-32, or similar), and calibration method, so long as you can prove the SPL matching is reliable and the Bluetooth hand-off stays in sync with the five-second delay. Weatherproofing is essential because the unit will live outside. Power can be mains with battery backup if that simplifies things.

Please send a detailed project proposal that covers hardware you would use, the signal-processing approach for real-time dB measurement and delay, and how you will validate the 55 dB gate as well as the playback level. A concise timeline and any previous work with audio DSP or environmental monitoring will help me pick the right person. Budget: USD 250–750 Skills: C Programming, Electronics, C++ Programming, Arduino, Bluetooth, Embedded Systems, Signal Processing, Audio Engineering