Techno Bears

I was only planning to have a quick play with the LCD display I bought recently, but ended up finishing off my Arduino + Home Easy polar bear controller project as well. Not that it actually needed a display you understand, but I’d wired it up, so why not!

…complete with a manual override should it annoy Jo a bit too much! I finished a bit ahead of schedule in the end; the polar bears aren’t actually out yet… because it’s not Christmas! I have dug the tree up though, and as soon as it’s indoors we’ll have some ambient bears to tell us when to turn something off. Here’s the sketch so far, warts and all:

#include <Bounce.h>
#include <HomeEasyCtrl.h>
#include <Messenger.h>
#include <LiquidCrystal.h>

#define WIRELESS 6
#define BUTTON 7
#define LED 13

// Define a metronome
unsigned long previousMillis = 0;

// Set the default interval to every 3 minutes -
//   enough time for a cup of tea
unsigned long interval = 180000;

// Instantiate a Bounce object with a 5 millisecond debounce time
Bounce bouncer = Bounce(BUTTON,5); 

// Instantiate Home Easy controller with transmitter on pin 4 and LED on 13
HomeEasyCtrl lightController(WIRELESS,LED);

// initialize the library with the numbers of the interface pins
LiquidCrystal lcd(12, 11, 10, 5, 4, 3, 2);

// Instantiate Messenger object with the message function and the default separator (the space character)
Messenger message = Messenger(); 

// Flag indicating the desired state of the lights
bool deviceOn = false;

// Flag indicating whether bears are on manual!
bool manual = false;

// Last energy reading in watts
int watts = 0;

// Energy use messages
int energyUse = 0;
char* energyUseMessages[]={"Energy: low", "Energy: normal", "Energy: high"};

// Define messenger function
void messageCompleted() {
 int elementCount = 0;
 int last = 0;
 Serial.println("Message received");

 // Loop through all the available elements of the message
 while ( message.available() ) {
 elementCount++;
 int value = message.readInt();

 if ((value == 0) || (elementCount > 2)) {
 Serial.println("Oops");
 return;
 }

 Serial.println(value, DEC);

 // wait for same value twice for simple
 // error checking
 if (value == last) {
 watts = value;
 } else {
 last = value;
 }
 }
 Serial.println("Watts");
 Serial.println(watts, DEC);

 checkEnergyUse();
}

void checkEnergyUse() {
 if (watts < 50 || watts > 350) {
 deviceOn = false;
 previousMillis = millis();
 // Don't mind waiting for things to go off
 if (watts < 50) {
 energyUse = 0; // low
 } else {
 energyUse = 2; // high
 }
 } else if (watts > 100 && watts < 300) {
 deviceOn = true;
 previousMillis = millis();
 energyUse = 1; // normal
 // Want things to come on immediately
 lightController.deviceOn();
 } // otherwise, no change

 updateDisplay();
}

void updateDisplay() {
 lcd.clear();

 // 1st line
 if (manual) {
 lcd.print("Manual override");
 } else {
 lcd.print(energyUseMessages[energyUse]);
 }

 // 2nd line
 lcd.setCursor(0,1);
 if (deviceOn) {
 lcd.print("Polar bears: on");
 } else {
 lcd.print("Polar bears: off");
 }
}

void setup() {
 pinMode(BUTTON,INPUT);

 // Initiate Serial Communication
 Serial.begin(9600); 

 // set up the LCD's number of rows and columns:
 lcd.begin(16, 2);
 lcd.print("Ready");
 lcd.setCursor(0,1);
 lcd.print("Polar bears: off");

 // set up incoming message processor
 message.attach(messageCompleted);
}

void loop() {

 // Check push button for manual override
 if ( bouncer.update() ) {
 if ( bouncer.read() == LOW) {
 if (!manual) {
 manual = true;
 deviceOn = true;
 lightController.deviceOn();
 } else {
 if (deviceOn) {
 deviceOn = false;
 lightController.deviceOff();
 } else {
 manual = false;
 checkEnergyUse();
 }
 }
 updateDisplay();
 }
 }

 // The following line is the most effective way of
 // feeding the serial data to Messenger
 while ( Serial.available( ) ) message.process(Serial.read( ) );

 // Keep the device in the desired state
 if ( millis() - previousMillis > interval ) {
 previousMillis = millis();

 if (deviceOn) {
 lightController.deviceOn();
 } else {
 lightController.deviceOff();
 }
 updateDisplay();
 }
}

No polar bears have been harmed in the making of this post. At least not yet anyway.

Update: Seems to be working quite well, although the manual override button seems to have problems- it seems to randomly flip back on when I want it to stay off. Still, the button works well enough to pair with a Home Easy socket which is the main thing. Tree and polar bears should be up this weekend. (16 Dec 2009)

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