This module could modulate your voice on the FM radio wave. And anyone who has a radio device could receive it. We build everything on this module, which makes it very easy to build a tiny radio station
The Hall Effect Sensor Module can be used to detect the presence of an magnetic field. If there is an magnetic field present, it will report a high level signal.
The DS3231SN is a low-cost, extremely accurate I²C real-time clock (RTC) with an integrated temperature-compensated crystal oscillator (TCXO) and crystal. The device incorporates a battery input, and maintains accurate timekeeping.