20pcs I2C 8-bit I/O Expander Module PCA8574AD Expansion Board RobotDyn for Arduino - products that work with official fo

Feature If you just don t have enough digital I O pins on your for Arduino to interface with all your sensors and controls you might want to look at using the I2C bus to connect a few port expander chip PCA8574AD have 8 digital I O bits and can be set to addresses 0x38 0x3F respectively The I2C bus on the for Arduino uses SCL SDA a couple of pull up resistors and the Wire library You can connect more expander module More 8 modules Just change the address of each module On the backside of the board have instruction If you need more connecting modules pls cut off the connection of pull up resistor on the back side of board Only 1 board needs a pull up resistor Package includes 20x Expansion Board