This simple circuit will allow you to multiplex as many sonar units as you want using a single processor input. Each sonar unit will require and output from the processor. This circuit is handy when you only have a limited number in interrupts or inputs available.

The circuit above will allow 3 sonar units to use a single processor input. 2N2222 transistors are used to make a special OR gate. Any unused inputs in this circuit must be tied to ground for the circuit to work. As many additional channels as needed may be added. We also offer a sonar and encoder driver board.