EC-Example-TrafficLight
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Traffic Light Example - EasyConnect
This example shows how to make and code a traffic light with RED-YELLOW-GREEN lights and a WHITE Walk Light.
The timing and sequencing of a traffic light is done with a "State Machine", which is a way to organize things like this so it doesn't get too confusing. It also reduces the chance of errors.
CODE Example: Traffic Light
Cut and Paste this into a blank Arduino IDE Window
/* YourSmartDuino-EM TRAFFIC SIGNAL: Example 8
- WHAT IT DOES: ***
- Uses the KEYES Easy-Plug Modules
- V3. 2/18/2019
Questions: terry@yourduino.com
- SEE the comments after "//" on each line below
- CONNECTIONS: KEYES Easy-Plug Control Board V2.0
NOTE: Different Software examples use a different sets of modules.
/*-----( Import needed libraries )-----*/
// ----------------------------------------------------------------------------
/*LiquidCrystal compability:
Since this hd44780 library is LiquidCrystal API compatible, most existing LiquidCrystal
sketches should work with hd44780 hd44780_I2Cexp i/o class once the
includes are changed to use hd44780 and the lcd object constructor is
changed to use the hd44780_I2Cexp i/o class.
*/
#include <Wire.h>
#include <hd44780.h> // main hd44780 header
#include <hd44780ioClass/hd44780_I2Cexp.h> // i2c expander i/o class header
/*----------------( Declare Constants and Pin Numbers )-------------------*/
//----( DIGITAL Pins)----
//----- ( 2 pins in socket labelled D3 D4 can be used for Ultrasonic )-----
#define ULTRA_TRIG_PIN 3 // Connect to socket labelled "D3D4
#define ULTRA_ECHO_PIN 4
#define BUZZER_PIN 5
#define RED_LIGHT 6 // Traffic Lights for specific example
#define YELLOW_LIGHT 7
#define GREEN_LIGHT 8
#define WALK_LIGHT 9
#define ONBOARD_LED_PIN 13
//----( DIGITAL INPUT Pins)----
#define REQUEST_WALK_PIN A0 // Digital request traffic wal
#define SWITCH_PIN A3 // Used for a variety of On-OFF Devices
//------( LOCAL DEFINITIONS )---------
#define ON 1
#define OFF 0
#define MAX_DISTANCE 300 // Maximum distance we want to ping for (in centimeters).
#define US_ROUNDTRIP_CM 58.2 // Ultrasonic Sensor constant
//-----( Traffic Control System States and definitions )-------
#define GREEN_STATE 0
#define CAUTION_STATE 1
#define RED_STATE 2
#define WALKING_STATE 3
#define WALK_FAST_STATE 4
#define MaxGreenSeconds 20
#define MinGreenSeconds 10
#define YellowSeconds 5
#define MaxRedSeconds 10
#define VehicleCloseCm 10 // Vehicle in sidestreet at light
/*--------------------( Declare objects )-------------------------*/
hd44780_I2Cexp lcd; // declare lcd object: auto locate & auto config expander chip
/*------------------------( Declare Variables )-----------------------------------*/
//***
boolean ShowedON = false;
boolean ShowedOFF = false;
int TrafficControlState = 0; // ---( For Traffic Light Control example )----
int StateDelaySeconds; // Variable set for Traffic Light sequence states
boolean VehicleDetected = false; //Set by Ultrasonic Distance Sensor
boolean TrafficSenseCall = false;
boolean WalkerSenseCall = false;
long duration_uS; // Duration used to calculate distance by Ultrasonic Sensor
int DistCM; // Measured distance in CM
void setup() /******************* SETUP: RUNS ONCE *************************/
{
Serial.begin(115200); // Start up the Serial Monitor
lcd.begin(16, 2); // initialize the lcd for 16 chars 2 lines, turn on backlight
lcd.noBacklight();
delay(500);
lcd.backlight(); // finish with backlight on
lcd.setCursor(0, 0); //Start at character 0 on line 0
lcd.print(F("EasyConnect By"));
lcd.setCursor(0, 1); //Start at character 0 on line 0
lcd.print(F("YourDuino.com"));
//
pinMode(ULTRA_TRIG_PIN, OUTPUT);
pinMode(ULTRA_ECHO_PIN, INPUT);
pinMode(BUZZER_PIN, OUTPUT);
pinMode(REQUEST_WALK_PIN, INPUT_PULLUP);
pinMode(GREEN_LIGHT, OUTPUT);
pinMode(YELLOW_LIGHT, OUTPUT);
pinMode(RED_LIGHT, OUTPUT);
pinMode(WALK_LIGHT, OUTPUT);
Serial.println("Option 18: TRAFFIC SIGNAL");
lcd.setCursor(0, 0); //Start at character 0 on line 0
//-----------1234567890123456----------
lcd.print(F("8:TRAFFIC LIGHT "));
StateDelaySeconds = MaxGreenSeconds;
TrafficSenseCall = false;
WalkerSenseCall = false;
delay(2000);
}//--(end setup )---
void loop() /********************** LOOP: RUNS CONSTANTLY ************************/
{
lcd.setCursor(0, 1); //Start at character 0 on line
//-------------------1234567890123456----------
lcd.print(F(" "));
lcd.setCursor(0, 1); //Start at character 0 on line
lcd.print(F("STATE="));
lcd.print(TrafficControlState);
delay(100);
if (SideStreetVehicleSense() == true)
{
TrafficSenseCall = true;
}
if (digitalRead(REQUEST_WALK_PIN) == 0)
{
WalkerSenseCall = true;
}
switch (TrafficControlState)
{
case GREEN_STATE:
{
Serial.println("GREEN");
lcd.setCursor(8, 1); //Start at character 9 on line
lcd.print(F("GREEN"));
digitalWrite(GREEN_LIGHT, ON);
digitalWrite(RED_LIGHT, OFF);
if (StateDelaySeconds >= 0)
{
lcd.setCursor(14, 1); //Start at character 14 on line
lcd.print(StateDelaySeconds);
delay(1000);
Serial.println(StateDelaySeconds);
StateDelaySeconds -= 1;
}
else
{
StateDelaySeconds = YellowSeconds;
TrafficControlState = CAUTION_STATE;
}
if ( (TrafficSenseCall | WalkerSenseCall)
& (StateDelaySeconds < MinGreenSeconds) )
{
Serial.println("Vehicle/Walker Sensed");
TrafficSenseCall = false;
StateDelaySeconds = YellowSeconds;
TrafficControlState = CAUTION_STATE;
}
}//End GREEN_STATE
break;
case CAUTION_STATE:
{
Serial.println("YELLOW");
lcd.setCursor(8, 1); //Start at character 9 on line
lcd.print(F("YELLOW"));
digitalWrite(GREEN_LIGHT, OFF);
digitalWrite(YELLOW_LIGHT, ON);
if (StateDelaySeconds >= 0)
{
lcd.setCursor(15, 1); //Start at character 14 on line
lcd.print(StateDelaySeconds);
delay(1000);
Serial.println(StateDelaySeconds);
StateDelaySeconds -= 1;
}
else
{
StateDelaySeconds = MaxRedSeconds;
TrafficControlState = RED_STATE;
}
TrafficSenseCall = false;
}//End CAUTION_STATE
break;
case RED_STATE:
{
Serial.println("RED");
lcd.setCursor(8, 1); //Start at character 9 on line
lcd.print(F("RED"));
digitalWrite(RED_LIGHT, ON);
digitalWrite(YELLOW_LIGHT, OFF);
if (StateDelaySeconds >= 0)
{
delay(1000);
Serial.println(StateDelaySeconds);
StateDelaySeconds -= 1;
}
else
{
StateDelaySeconds = MaxGreenSeconds;
TrafficControlState = GREEN_STATE;
}
if (WalkerSenseCall)
{
Serial.println("Walker Sensed");
WalkerSenseCall = false;
TrafficControlState = WALKING_STATE;
}
}
break;
case WALKING_STATE:
{
Serial.println("WALKING");
lcd.setCursor(8, 1); //Start at character 9 on line
lcd.print(F("WALKING"));
digitalWrite(BUZZER_PIN, ON);
delay(100);
digitalWrite(BUZZER_PIN, OFF);
delay(100);
digitalWrite(BUZZER_PIN, ON);
delay(100);
digitalWrite(BUZZER_PIN, OFF);
delay(700);
digitalWrite(WALK_LIGHT, ON);
delay(5000);
digitalWrite(WALK_LIGHT, OFF);
StateDelaySeconds = 4;
TrafficControlState = WALK_FAST_STATE;
}
break;
case WALK_FAST_STATE:
{
Serial.println("WALK FAST");
lcd.setCursor(8, 1); //Start at character 9 on line
lcd.print(F("RUN ! !"));
if (StateDelaySeconds >= 0)
{
delay(500);
digitalWrite(WALK_LIGHT, ON);
digitalWrite(BUZZER_PIN, ON);
delay(500);
digitalWrite(WALK_LIGHT, OFF);
digitalWrite(BUZZER_PIN, OFF);
Serial.println(StateDelaySeconds);
StateDelaySeconds -= 1;
}
else
{
delay(2000);
StateDelaySeconds = MaxGreenSeconds;
TrafficControlState = GREEN_STATE;
WalkerSenseCall = false;
}
}
break;
delay(500);
} //End Switch on TrafficControlState
}//--(end main loop )---
/*--------------------( Declare User-written Functions )------------------------*/
boolean SideStreetVehicleSense()
{
/* The following trigPin/echoPin cycle is used to determine the
distance of the nearest object by bouncing soundwaves off of it. */
digitalWrite(ULTRA_TRIG_PIN, LOW); // Pulse the Trigger pin High and then Low
delayMicroseconds(2);
digitalWrite(ULTRA_TRIG_PIN, HIGH);
delayMicroseconds(10);
digitalWrite(ULTRA_TRIG_PIN, LOW);
duration_uS = pulseIn(ULTRA_ECHO_PIN, HIGH);
//Calculate the distance (in cm) based on the speed of sound.
DistCM = duration_uS / US_ROUNDTRIP_CM; // Calculate distance in CM
Serial.print("DistCM = ");
Serial.println(DistCM);
if (DistCM <= VehicleCloseCm)
return true;
else
return false;
}// END CheckSideStreet
//*********( THE END )***********