[Barclay]

Ho fatto così:

#include "Plafo.h"
#include <Wire.h>
#include "RTClib.h"

RTC_DS1307 RTC;

Plafo plafo;

void setup(void) {
  
  Serial.begin(57600);
  Wire.begin();
  RTC.begin();
  
  if (! RTC.isrunning()) {
    Serial.println("RTC is NOT running!");
    RTC.adjust(DateTime(__DATE__, __TIME__));
  }
 
 
  //Channel,startHour,startMinute,endHour,endMinute,fadeLen,maxPWM,pin
  plafo.setChannel(blue,18,0,4,0,30,180,7);//Dalle 18.00 alle 4.00, alba/tramonto 30 minuti, pwm massimo 180, pin 7  
  plafo.setChannel(white,18,15,3,45,75,180,5);//Dalle 18.15 alle 3.45, alba/tramonto 75 minuti
  plafo.setChannel(uv,19,30,2,30,0,HIGH,22);//Dalle 19.30 alle 2.30, accensione immediata, pin 22 (digitale)
  plafo.setChannel(moon,4,10,7,0,0,HIGH,23);//Dalle 4.10 alle 7.00
}

void loop(void) {
  
  DateTime now = RTC.now();
 
    Serial.print(now.year(), DEC);
    Serial.print('/');
    Serial.print(now.month(), DEC);
    Serial.print('/');
    Serial.print(now.day(), DEC);
    Serial.print(' ');
    Serial.print(now.hour(), DEC);
    Serial.print(':');
    Serial.print(now.minute(), DEC);
    Serial.print(':');
    Serial.print(now.second(), DEC);
    Serial.println();
 
    Serial.print(" since 1970 = ");
    Serial.print(now.unixtime());
    Serial.print("s = ");
    Serial.print(now.unixtime() / 86400L);
    Serial.println("d");
 
    // calculate a date which is 7 days and 30 seconds into the future
    DateTime future (now.unixtime() + 7 * 86400L + 30);
 
    Serial.print(" now + 7d + 30s: ");
    Serial.print(future.year(), DEC);
    Serial.print('/');
    Serial.print(future.month(), DEC);
    Serial.print('/');
    Serial.print(future.day(), DEC);
    Serial.print(' ');
    Serial.print(future.hour(), DEC);
    Serial.print(':');
    Serial.print(future.minute(), DEC);
    Serial.print(':');
    Serial.print(future.second(), DEC);
    Serial.println();
 
    Serial.println();
    delay(1000);

  
  
  //Sostituire "hour","minute", "second" con le variabili dichiarate sul vostro progetto, che contengono rispettivamente l'ora, i minuti e i secondi correnti.
  plafo.perform(8,0,0);

}

ma mi da una sfilza di errori...
il formato orario che inserisco a fine codice è corretto?
Scusa, ma come puoi immaginare sono proprio ai primordi.
------------------------------------------------------------------------
Ecco gli errori

Plafo\plafo.cpp.o: In function `Plafo::elapsedTimeToSecond(unsigned char, unsigned char, unsigned char, unsigned char, unsigned char, unsigned char)':
C:\Programmi\Arduino\libraries\Plafo/plafo.cpp:91: multiple definition of `Plafo::elapsedTimeToSecond(unsigned char, unsigned char, unsigned char, unsigned char, unsigned char, unsigned char)'
plafo.cpp.o:C:\DOCUME~1\Piero\IMPOST~1\Temp\build8057541304359831578.tmp/plafo.cpp:91: first defined here
c:/programmi/arduino/hardware/tools/avr/bin/../lib/gcc/avr/4.3.2/../../../../avr/bin/ld.exe: Disabling relaxation: it will not work with multiple definitions
Plafo\plafo.cpp.o: In function `Plafo::performChannel(void*, unsigned char, unsigned char, unsigned char)':
C:\Programmi\Arduino\libraries\Plafo/plafo.cpp:49: multiple definition of `Plafo::performChannel(void*, unsigned char, unsigned char, unsigned char)'
plafo.cpp.o:C:\DOCUME~1\Piero\IMPOST~1\Temp\build8057541304359831578.tmp/plafo.cpp:49: first defined here
Plafo\plafo.cpp.o: In function `Plafo::perform(unsigned char, unsigned char, unsigned char)':
C:\Programmi\Arduino\libraries\Plafo/plafo.cpp:37: multiple definition of `Plafo::perform(unsigned char, unsigned char, unsigned char)'
plafo.cpp.o:C:\DOCUME~1\Piero\IMPOST~1\Temp\build8057541304359831578.tmp/plafo.cpp:37: first defined here
Plafo\plafo.cpp.o: In function `Plafo::elapsedTimeToSecond(unsigned char, unsigned char, unsigned char, unsigned char, unsigned char, unsigned char)':
C:\Programmi\Arduino\libraries\Plafo/plafo.cpp:91: multiple definition of `lastSecond'
plafo.cpp.o:C:\DOCUME~1\Piero\IMPOST~1\Temp\build8057541304359831578.tmp/plafo.cpp:91: first defined here
Plafo\plafo.cpp.o: In function `Plafo::elapsedTimeToSecond(unsigned char, unsigned char, unsigned char, unsigned char, unsigned char, unsigned char)':
C:\Programmi\Arduino\libraries\Plafo/plafo.cpp:91: multiple definition of `channels'
plafo.cpp.o:C:\DOCUME~1\Piero\IMPOST~1\Temp\build8057541304359831578.tmp/plafo.cpp:91: first defined here
Plafo\plafo.cpp.o: In function `Plafo::setChannel(int, unsigned char, unsigned char, unsigned char, unsigned char, unsigned int, unsigned char, unsigned char)':
C:\Programmi\Arduino\libraries\Plafo/plafo.cpp:24: multiple definition of `Plafo::setChannel(int, unsigned char, unsigned char, unsigned char, unsigned char, unsigned int, unsigned char, unsigned char)'
plafo.cpp.o:C:\DOCUME~1\Piero\IMPOST~1\Temp\build8057541304359831578.tmp/plafo.cpp:24: first defined here
Plafo\plafo.cpp.o: In function `Plafo':
C:\Programmi\Arduino\libraries\Plafo/plafo.cpp:14: multiple definition of `Plafo::Plafo()'
plafo.cpp.o:C:\DOCUME~1\Piero\IMPOST~1\Temp\build8057541304359831578.tmp/plafo.cpp:14: first defined here
Plafo\plafo.cpp.o: In function `Plafo':
C:\Programmi\Arduino\libraries\Plafo/plafo.cpp:14: multiple definition of `Plafo::Plafo()'
plafo.cpp.o:C:\DOCUME~1\Piero\IMPOST~1\Temp\build8057541304359831578.tmp/plafo.cpp:14: first defined here