/* KeyPressed on PIN1 by Mischianti Renzo https://www.mischianti.org/2019/01/02/pcf8574-i2c-digital-i-o-expander-fast-easy-usage/ */ #include "Arduino.h" #include "PCF8574.h" // Set i2c address PCF8574 pcf8574(0x39); unsigned long timeElapsed; void setup() { Serial.begin(115200); delay(1000); pcf8574.pinMode(P0, OUTPUT); pcf8574.pinMode(P1, INPUT); Serial.print("Init pcf8574..."); if (pcf8574.begin()){ Serial.println("OK"); }else{ Serial.println("KO"); } } void loop() { uint8_t val = pcf8574.digitalRead(P1); if (val==HIGH) Serial.println("KEY PRESSED"); delay(50); }