CD74HC4067 board for the very handy 16-Channel Analog/Digital Multiplexer/Demultiplexer, use the CD74HC4067 16-channel analog signal switch;Analog signal input: C0-C15 16 channels; Analog output: DIG; Channel control: S0-S3 It works with both digital and analog signals (the voltage can't be higher than VCC), and the connections function in either direction.If you want two-way communications,you can add a second board to route your microcontroller's TX line to 16 device's RX lines. By using multiple boards, you can create similar arrangements for I2C,SPI,etc. The internal switches are bidirectional, support voltages between ground and VCC, have low "on" resistance and low "off" leakage, and to prevent crosstalk, perform "break-before-make" switching. The board also breaks out the chip's "enable" pin, which when driven high, will completely disconnect the common pin (all switches "off"). To control it, digital outputs to the chip's address select pins (S0-S3), and send it the binary address of the channel you want. This allows you to connect up to 16 sensors to your system using only 5 pins. Since the mux/demux also works with digital signals, you can use it to pipe TTL level serial data to or from multiple devices. For example, you could use it to connect the TX pins of 16 devices to one RX pin on your microcontroller. You can then select any one of those 16 devices to listen to. Material:plastic colour:blue Package Contents: 12 * CD74HC4067 16 channel analog module Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.