LED Dimming library

[Panos Toumpaniaris]

Ok, before reading further, take note that this is my very first attempt at anything c++ like, with virtually no programming background.
I cannot be held responsible for anything or everything going wrong, although it's probably relatevily safe..
However if you led strips come to life and start chasing your cat, please do post a video!

Having said that, here's the problem: Having two or more led lights/strips to be dimmed on the same node. You can have up to 6 on Nano, 14 on Mega and 11 on Due, so there are a lot of options.

The example sketch in the Build section uses the dreaded delay(), so nothing can be done while the light dims.
Replacing it with gw.wait() makes the entire dimming process rather unpredictable if a message is received while dimming. Noone knows where it's going to stop.

My (crude and amateurish) solution : https://github.com/ptoump/LedDimmer

It's a library which provides you with a LedDimming class keeping the state machine philosophy of arduino multi-task programming.

Each LedDimmer object comes with a constructor LedDimmer(int led_pin), a state changing routine dim(int time_step, int target_level) and an updater, update().

Here's some example code :

#define SN "DimLED_x2_bsm"
#define SV "1.4"

#include <MySensor.h> 
#include <SPI.h>
#include <MyTransportNRF24.h>
#include <MyHwATMega328.h>
#include <LedDimmer.h>

// Uncomment the following line to enable debug
// #define DEBUG_Local 

#ifdef DEBUG_Local
#define DEBUG_Local_SERIAL(x) Serial.begin(x)
#define DEBUG_Local_PRINT(x) Serial.print(x)
#define DEBUG_Local_PRINTLN(x) Serial.println(x)
#else
#define DEBUG_Local_SERIAL(x)
#define DEBUG_Local_PRINT(x) 
#define DEBUG_Local_PRINTLN(x) 
#endif

#define LED1_PIN 9      // Arduino pin attached to MOSFET Gate pin
#define LED2_PIN 10      // Arduino pin attached to MOSFET Gate pin

#define LED1_CHILD 0           // Id of 1st LED strip child
#define LED2_CHILD 1           // Id of 2nd LED strip child

// Please note the CE,CS PINS !!!!
MyTransportNRF24 transport(7, 8, RF24_PA_MAX);
MyHwATMega328 hw;
MySensor gw(transport, hw);

const int ledpins[] = {LED1_PIN,LED2_PIN};
const int fade_period = 3 * 1000;     // fade time in ms

LedDimmer dim1(ledpins[0]);
LedDimmer dim2(ledpins[1]);

MyMessage dim1Msg(LED1_CHILD, V_DIMMER);
MyMessage dim2Msg(LED2_CHILD, V_DIMMER);


/***
 * Dimmable LED initialization method
 */
 
void setup()  
{ 
  DEBUG_Local_SERIAL(115200);    
  DEBUG_Local_PRINTLN("Serial started");
   
  gw.begin( incomingMessage );
  gw.sendSketchInfo(SN, SV);
    
  // Register the LED Dimmable Light with the gateway
  gw.present( LED1_CHILD, S_DIMMER );
  gw.present( LED2_CHILD, S_DIMMER );
    
  // Pull the gateway's current dim level - restore light level upon sendor node power-up
  gw.request( LED1_CHILD, V_DIMMER );
  gw.request( LED2_CHILD, V_DIMMER );
}

/***
 *  Dimmable LED main processing loop 
 */
void loop() 
{
  gw.process();
  dim1.update();
  dim2.update();
}



void incomingMessage(const MyMessage &message) {
  if (message.type == V_LIGHT || message.type == V_DIMMER) {

    int led2dim = message.sensor ;
    
    //  Retrieve the power or dim level from the incoming request message
    int requestedLevel = atoi( message.data );
    
    // Adjust incoming level if this is a V_LIGHT variable update [0 == off, 1 == on]
    requestedLevel *= ( message.type == V_LIGHT ? 100 : 1 );
    
    // Clip incoming level to valid range of 0 to 100
    requestedLevel = requestedLevel > 100 ? 100 : requestedLevel;
    requestedLevel = requestedLevel < 0   ? 0   : requestedLevel;
    
    DEBUG_Local_PRINT( "Changing led no [ ");
    DEBUG_Local_PRINT( led2dim );
    DEBUG_Local_PRINT( " ] level to " );
    DEBUG_Local_PRINTLN( requestedLevel );
    
     
    switch (led2dim) {
      case 0:
          dim1.dim(dim1.calcStep(fade_period, requestedLevel), requestedLevel); 
      break;

      case 1:
         dim2.dim(dim2.calcStep(fade_period, requestedLevel), requestedLevel);
      break;
    } //*/
  }  // ENDIF messagetype


    
}

Now group your dimmers together and have them change state at the same time..... Magic!!

I hope you find it usefull!

panos