Things used in this project

Hardware components:
A000066 iso both
Arduino Arduino UNO & Genuino UNO
grove shield
connector for grove sensors to arduino
grove RFID reader and tags
to identify a cup/user
grove LED
to indicate whether a cup has been detected
grove light intensity sensor
detection of a cup
grove relay
to trigger the coffee machine to make some
grove button
for the user to choose to take some coffee (perhaps after getting a warning)


Hackaton_CoffeeMachine.txtPlain text
Arduino sketch, disclaimer: this sketch still has some debugging to do
#include <Ethernet.h>			        //for loading components required by the iot device object.
#include <EthernetClient.h>
#include <PubSubClient.h>

#include <ATT_IOT.h> // SmartLiving for Makers Arduino Library
#include <SPI.h>                                //required to have support for signed/unsigned long type.	
#include <SoftwareSerial.h>			

char deviceId[] = ""; // Your device id comes here
char clientId[] = ""; // Your client id comes here;
char clientKey[] = ""; // Your client key comes here;

ATTDevice Device(deviceId, clientId, clientKey);            //create the object that provides the connection to the cloud to manager the device.
char httpServer[] = "";                  	// HTTP API Server host
char* mqttServer = "";                   

int rfid = 2;                                            // Digital 8 is the input pin, this corresponds with the number on the Grove shiled where the push button is attached to
int led = 5;                                             // Pin 8 is the LED pin and it's also used to construct the AssetID
int button = 8;
int lightsensor = 0;
int validcup = 100;
int relay = 4;

SoftwareSerial SoftSerial(2, 3);
// unsigned char buffer[64]; // buffer array for data recieve over serial port
char buffer[64]; // buffer array for data recieve over serial port
int count=0;     // counter for buffer array 

String currentRFIDconnected = "";
String supportedRFIDs[] = {"2300FB4B0A99", "BBBB"};
int coffeeCount[] = {0, 0};

//required for the device
void callback(char* topic, byte* payload, unsigned int length);
EthernetClient ethClient;
PubSubClient pubSub(mqttServer, 1883, callback, ethClient);

void setup()
  pinMode(led, OUTPUT);                                  // initialize the digital pin as an output.         
  pinMode(rfid, INPUT);                                  // initialize the digital pin as an output.         
  pinMode(button, INPUT);
  pinMode(lightsensor, INPUT);
  pinMode(validcup, INPUT);
  pinMode(relay, OUTPUT);                                  // initialize the digital pin as an output.         
  Serial.begin(9600);                               	// init serial link for debugging
  byte mac[] = {  0x90, 0xA2, 0xDA, 0x0D, 0x8C, 0xC1 }; 	    // Adapt to your Arduino MAC Address  
  if (Ethernet.begin(mac) == 0)                             // Initialize the Ethernet connection:
    Serial.println(F("DHCP failed,end"));
    while(true);                                    		//we failed to connect, halt execution here. 
  delay(1000);                                          	//give the Ethernet shield a second to initialize:
  if(Device.Connect(&ethClient, httpServer))                //connect the device with the IOT platform.
    Device.AddAsset(rfid, "rfid", "RFID Reader",false, "String");
    Device.AddAsset(button, "button", "Button",false, "bool");
    Device.AddAsset(led, "led", "light emitting diode", true, "bool");
    Device.AddAsset(lightsensor, "lightsensor", "sensor of light", false, "int");
    Device.AddAsset(validcup, "valid cup", "valid cup", false, "bool");
    Device.AddAsset(relay, "toggle machine on", "toggle coffee machine", true, "bool");
    Device.Subscribe(pubSub);                               // make certain that we can receive message from the iot platform (activate mqtt)
  } else {
    while(true);                                            //can't set up the device on the cloud, can't continue, so put the app in an ethernal loop so it doesn't do anything else anymore.                              

unsigned long time;                                 		//only send every x amount of time.
unsigned int prevVal =0;
bool canTakeCoffee = false;

void loop()
  unsigned int r = analogRead(lightsensor);
  if(r < 600){
    //there is a cup, is there an rfid tag
    if (SoftSerial.available())              // if date is comming from softwareserial port ==> data is comming from SoftSerial shield
      while(SoftSerial.available())          // reading RFID data into char array 
        buffer[count++];     // writing RFID data into array
        if(count == 64)break;
      Device.Send(buffer, rfid);       // Sned RFID dara to SmartLiving
        digitalWrite(led, HIGH);
        digitalWrite(led, LOW);
        digitalWrite(led, HIGH);
        digitalWrite(led, LOW);
        digitalWrite(led, HIGH);
        digitalWrite(led, LOW);
          if(coffeeCount[0] < 3){
            digitalWrite(relay, HIGH);

      clearBufferArray();              // call clearBufferArray function to clear the storaged data from the array
      count = 0;                       // set counter of while loop to zero
      digitalWrite(validcup, HIGH);
  } else {
    digitalWrite(validcup, LOW);
    digitalWrite(relay, LOW);
    digitalWrite(led, LOW);
    Device.Send("no cup", rfid);

  String buttonState = "false";
    buttonState = "true";
  String validCupState = "false";
    validCupState = "true";  
  Device.Send(buttonState, button);
  Device.Send(String(analogRead(lightsensor)), lightsensor);
  Device.Send(validCupState, validcup);
  if (Serial.available())            // if data is available on hardwareserial port ==> data is comming from PC or notebook
    SoftSerial.write(;       // write it to the SoftSerial shield

void clearBufferArray()              // function to clear buffer array
  for (int i=0; i<count;i++)
    { buffer[i]=NULL;}                  // clear all index of array with command NULL

// Callback function: handles messages that were sent from the iot platform to this device.
void callback(char* topic, byte* payload, unsigned int length) 
  String msgString; 
  {                                                     //put this in a sub block, so any unused memory can be freed as soon as possible, required to save mem while sending data
    char message_buff[length + 1];                      //need to copy over the payload so that we can add a /0 terminator, this can then be wrapped inside a string for easy manipulation.
    strncpy(message_buff, (char*)payload, length);      //copy over the data
    message_buff[length] = '\0';                        //make certain that it ends with a null         
    msgString = String(message_buff);
    msgString.toLowerCase();                            //to make certain that our comparison later on works ok (it could be that a 'True' or 'False' was sent)
  int* idOut = NULL;
  {                                                     //put this in a sub block, so any unused memory can be freed as soon as possible, required to save mem while sending data
    int pinNr = Device.GetPinNr(topic, strlen(topic));
    Serial.print("Payload: ");                          //show some debugging.
    Serial.print("topic: ");
    if (pinNr == led)       
      if (msgString == "false") {
        digitalWrite(led, LOW);                      //change the led    
        idOut = &led;                                
      else if (msgString == "true") {
        digitalWrite(led, HIGH);
        idOut = &led;
  if(idOut != NULL)                                     //also let the iot platform know that the operation was succesful: give it some feedback. This also allows the iot to update the GUI's correctly & run scenarios.
    Device.Send(msgString, *idOut);    



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