It had been a long time since i wanted to make a building automation system. In fact it was the first product i ever dream&#x2019;t of making. Time passed and i didn&#x2019;t quite find the time and interest to venture into it as i felt that building automation is a old concept and there are too many players doing the same stuff.<br><br>So i designed this board, which can control the relays on board, based on the inputs provided either from cloud or from a call using DTMF.<br><br>Features :<br>For the first iteration we designed it to have the following features,<br><br>4 cube Relays driven by MOSFET&#x2019;s to control 110V to 230V AC appliances<br>SIM800C 2G Quadband GSM module for cloud/call connectivity with micro SIM card connector<br>External Whip Antenna with right angle SMA connector<br>MP3 player with micro SD card<br>STM32 Cortex M0 Low power MCU with RTC<br>Switching power supply to take inputs from 5V to 24V DC<br>DC power jack for power input<br>SWD connector for programmi