Quelltext der Seite Switching power with the Arduino over a I2C connected PCF8574

== Goal ==

This little project wants do demonstrate how it is possible to switch a great number of lines with one single Arduino controller. It uses the PCF8574P chip. It is actually a reimplementation of this project:

* http://circuitsforbeginners.blogspot.com/2009/11/project-rolling-dice-expanding-arduino.html

== References ==

* http://www.arduino.cc/en/Reference/Wire The WIRING "Wire" library
* http://www.neufeld.newton.ks.us/electronics/?p=241 A project in which the workings of the I2C protocol are well described
* www.nxp.com/documents/data_sheet/PCF8574.pdf The Datasheet for the PCF8574

== The Scheme ==

[[Image:pcf8574_i2c.jpg|400px]]

== The Code ==

 #define CARD_ADR (0x4 << 3 | 0x0) // address 0100000
 
 #include <Wire.h>
 
 void setup()
 {
   Wire.begin(); // join i2c bus (address optional for master)
 }
 
 void loop()
 {
   /* switch on P0 */
   Wire.beginTransmission(CARD_ADR);
   Wire.send(B00000001);
   Wire.endTransmission();
   delay(1000);
  
   /* switch off all pins */
   Wire.beginTransmission(CARD_ADR);
   Wire.send(B00000000);
   Wire.endTransmission();
   delay(1000);   
 
   /* switch on P1 */
   Wire.beginTransmission(CARD_ADR);
   Wire.send(B00000010);
   Wire.endTransmission();
   delay(1000);
  
   /* switch off all pins */
   Wire.beginTransmission(CARD_ADR);
   Wire.send(B00000000);
   Wire.endTransmission();
   delay(1000);   
  
 }


== The Movie ==

You can watch the movie which explains this subproject on my Youtube channel.