Whether it is a library, conference room, school classroom, or some other public space, we all require peace and quiet to work sometimes, but achieving it can be a challenge. After wondering if loudmouths could be automatically asked to be silent via some kind of sensor-driven system, Bas op ten Berg, the founder of BotBerg, chose to build one using just a few components.
His smart shusher is based on the Arduino Nano 33 BLE Sense board and its built-in MP34DT05 MEMS microphone element. By reading in the pulse-density modulation (PDM) value from the output pin, he could easily convert it into the sound pressure, and thus the ambient noise level. Setting the noise threshold is done by carefully adjusting a connected potentiometer that gets read multiple times per second from an analog input pin. When the set threshold has been exceeded for a predetermined amount of time, a DFRobot MP3 player module is triggered and plays a sound file containing the phrase “Pssst, silence please! Silence please!” which is sure to grab anyone’s interest. All of the parts are housed within an equally attention-grabbing 3D printed lower face so that it appears to be speaking.
Beyond this local, offline functionality, op ten Berg offers other ways to expand the project, including ideas such as BLE connectivity, extra sounds/lights, or even switching on a relay. More details can be found on his website.
Read more about this on: Arduino Blog