Simple Hand Wash Timer

1/*
2 *   DISTANCE SENSOR:
3        VCC: 5V
4        Trigger to Pin   8
5        Echo to Pin 9
6        GND to GND
7
8      The LCD:
9 * LCD   RS pin to digital pin 12
10 * LCD Enable pin to digital pin 11
11 * LCD D4 pin   to digital pin 5
12 * LCD D5 pin to digital pin 4
13 * LCD D6 pin to digital pin   3
14 * LCD D7 pin to digital pin 2
15 * LCD R/W pin to ground
16 * LCD VSS pin   to ground
17 * LCD VCC pin to 5V
18 * 10K resistor:
19 * ends to 5V and ground
20   * wiper to LCD VO pin (pin 3)    
21 * 
22 * 
23 *    The buzzer:
24 * posotive   leg to pin 7
25 * negaitive leg to gnd
26 */
27 
28#include <LiquidCrystal.h>
29LiquidCrystal   lcd(12, 11, 5, 4, 3, 2);
30
31int buzzerPin = 7;
32int trigPin = 8;    
33int   echoPin = 9;    
34int handDistance = 2000;   //this will vary depending on how   big your sink is. If the closest object is less than handDistance, then the countdown   starts. Use the serial monitor to determine what it's value shoud be. 
35 
36void   setup() {
37  //begin serial monitor
38  Serial.begin (9600);
39  //specify inputs   and outputs
40  pinMode(trigPin, OUTPUT);
41  pinMode(echoPin, INPUT);
42  //The   LCD has 16 columns and two rows
43  lcd.begin(16, 2);
44  // Start writing at   this point
45  lcd.setCursor(0, 2);
46}
47 
48void loop() {
49  //clear the   LCD
50  lcd.clear();
51  // Print to the LCD
52  lcd.print("Hand wash timer");
53   // Use the distance sensor
54  digitalWrite(trigPin, LOW);
55  delayMicroseconds(5);
56   digitalWrite(trigPin, HIGH);
57  delayMicroseconds(10);
58  digitalWrite(trigPin,   LOW);
59  int distance = pulseIn(echoPin, HIGH);
60  // Print to the Serial Monitor   (optional)
61  Serial.println(distance);
62
63
64  // if the nearest object   is less then 2000 units away...
65  if (distance < handDistance){
66    //sounds   buzzer
67  tone(buzzerPin, 1000, 1000);
68  // repeats the code that tells how   many seconds are left for thrity seconds
69    for (int i = 30; i  > 0; --i){
70       lcd.setCursor(0, 1);
71      lcd.print(i);
72      delay(1000);
73      lcd.setCursor(0,   1);
74      lcd.print("  ");
75    }
76    //sounds the buzzer after the thirty   seconds are up
77    tone(buzzerPin, 1000, 2500);
78    
79  }
80
81  delay(500);
82   
83  
84
85}

1/*
2 *   DISTANCE SENSOR:
3        VCC: 5V
4        Trigger to Pin  8
5        Echo to Pin 9
6        GND to GND
7
8      The LCD:
9 * LCD  RS pin to digital pin 12
10 * LCD Enable pin to digital pin 11
11 * LCD D4 pin  to digital pin 5
12 * LCD D5 pin to digital pin 4
13 * LCD D6 pin to digital pin  3
14 * LCD D7 pin to digital pin 2
15 * LCD R/W pin to ground
16 * LCD VSS pin  to ground
17 * LCD VCC pin to 5V
18 * 10K resistor:
19 * ends to 5V and ground
20  * wiper to LCD VO pin (pin 3)    
21 * 
22 * 
23 *    The buzzer:
24 * posotive  leg to pin 7
25 * negaitive leg to gnd
26 */
27 
28#include <LiquidCrystal.h>
29LiquidCrystal  lcd(12, 11, 5, 4, 3, 2);
30
31int buzzerPin = 7;
32int trigPin = 8;    
33int  echoPin = 9;    
34int handDistance = 2000;   //this will vary depending on how  big your sink is. If the closest object is less than handDistance, then the countdown  starts. Use the serial monitor to determine what it's value shoud be. 
35 
36void  setup() {
37  //begin serial monitor
38  Serial.begin (9600);
39  //specify inputs  and outputs
40  pinMode(trigPin, OUTPUT);
41  pinMode(echoPin, INPUT);
42  //The  LCD has 16 columns and two rows
43  lcd.begin(16, 2);
44  // Start writing at  this point
45  lcd.setCursor(0, 2);
46}
47 
48void loop() {
49  //clear the  LCD
50  lcd.clear();
51  // Print to the LCD
52  lcd.print("Hand wash timer");
53  // Use the distance sensor
54  digitalWrite(trigPin, LOW);
55  delayMicroseconds(5);
56  digitalWrite(trigPin, HIGH);
57  delayMicroseconds(10);
58  digitalWrite(trigPin,  LOW);
59  int distance = pulseIn(echoPin, HIGH);
60  // Print to the Serial Monitor  (optional)
61  Serial.println(distance);
62
63
64  // if the nearest object  is less then 2000 units away...
65  if (distance < handDistance){
66    //sounds  buzzer
67  tone(buzzerPin, 1000, 1000);
68  // repeats the code that tells how  many seconds are left for thrity seconds
69    for (int i = 30; i  > 0; --i){
70      lcd.setCursor(0, 1);
71      lcd.print(i);
72      delay(1000);
73      lcd.setCursor(0,  1);
74      lcd.print("  ");
75    }
76    //sounds the buzzer after the thirty  seconds are up
77    tone(buzzerPin, 1000, 2500);
78    
79  }
80
81  delay(500);
82  
83  
84
85}