If you have something that needs to be turned on and off why not do it in a unique way. This Sound-Activated Outlet project lets us use an Arduino to monitor for sound patterns and then control an outlet accordingly.Â
“The circuit for this project can be divided into two main parts: A microphone assembly and a relay driver.
The microphone assembly is composed of an electret microphone element, two resistors, and a capacitor. When the microphone picks up sound vibrations, the output voltage fluctuates in response. This signal is sent to one of the analog input pins on the Arduino.
The relay driver is composed of a power MOSFET transistor, a diode, and a relay. The power transistor is added because the relay requires more current than the digital pins on the Arduino can output. So the output signal that is sent from the digital pin activates the transistor and the transistor connects power to the relay and turns it on. The relay either connects or disconnects power from the AC outlet to the attached appliance. The diode acts as a suppression diode and protects the Arduino from voltage spikes that occur when the relay is turned off. If you don’t want to build a relay driver from scratch, you can use a commercial relay shield or a PowerSwitch Tail.”