High Speed Analog / Digital MUX Breakout CD74HC4067 for Arduino
If you are running out of digital pins to control a 16-channel relay on your Arduino Uno? One thing comes in mind to upgrade to an Arduino Mega. But no, that's not the only workaround available. You could use a demultiplexer to increase the number of pins you can control or access by addressing them.
This module uses a CD74HC4067, a multiplexer/demultiplexer IC that can connect 16 other components using just 6 pins from Arduino. It can be as bidirectional switches, thus allowing any analog input to change as an output and vice-versa.
It can operate with 2V to 6V power supply with a wide operating temperature range: -55C to 125C.
This module needs 6 pins from the Arduino; 2 for your power(VCC/GND), 4 of which is for the addressing of the output pin, 1 for the signal (HIGH/LOW), and 1 for enabling pin. When the enabling pin is high, it disconnects the Common pin.
You may use this in a project that uses many components, but with a little memory usage that the Arduino board can handle.