Schematic and Photo Of Arduino PCF8574 I2C LCD Keypad Shield

  My PCF8574 I2C LCD Keypad Shield has been completed. The benefit of I2C LCD Keypad Shield over LCD Keypad Shield is that it free up 6 digital I/O used by LCD Keypad Shield for other use.
  The schematic used is version 1.1 other than the version 1.0 posted on Feb. 28, 2014. The difference between version 1.1 and version 1.0 is that the version 1.1 has a 4-pins I2C connector as shown on the bottom-left corner of the shield on the photo to act a either a shield or a breakout. When the shield serves as a breakout, the 5-way button cannot function. The sketch runs is same as the one posted on Feb. 28, 2014.

  When the shield is stacked directly upon the Arduino Uno, it should be noticed avoiding the pins of PCF8574 touching the shield of USB type B connector of Arduino. A insulated stick is a simple way. It is recommend to use Arduino boards with mini or micro USB connector such as Leonardo or stack on any other shield.


Schematic

Photo