| /* | |
| Arduino Starter Kit example | |
| Project 12 - Knock Lock | |
| This sketch is written to accompany Project 12 in the Arduino Starter Kit | |
| Parts required: | |
| - 1 megohm resistor | |
| - 10 kilohm resistor | |
| - three 220 ohm resistors | |
| - piezo | |
| - servo motor | |
| - push button | |
| - one red LED | |
| - one yellow LED | |
| - one green LED | |
| - 100 uF capacitor | |
| created 18 Sep 2012 | |
| by Scott Fitzgerald | |
| Thanks to Federico Vanzati for improvements | |
| https://store.arduino.cc/genuino-starter-kit | |
| This example code is part of the public domain. | |
| */ | |
| // import the library | |
| // create an instance of the Servo library | |
| Servo myServo; | |
| const int piezo = A0; // pin the piezo is attached to | |
| const int switchPin = 2; // pin the switch is attached to | |
| const int yellowLed = 3; // pin the yellow LED is attached to | |
| const int greenLed = 4; // pin the green LED is attached to | |
| const int redLed = 5; // pin the red LED is attached to | |
| // variable for the piezo value | |
| int knockVal; | |
| // variable for the switch value | |
| int switchVal; | |
| // variables for the high and low limits of the knock value | |
| const int quietKnock = 10; | |
| const int loudKnock = 100; | |
| // variable to indicate if locked or not | |
| bool locked = false; | |
| // how many valid knocks you've received | |
| int numberOfKnocks = 0; | |
| void setup() { | |
| // attach the servo to pin 9 | |
| myServo.attach(9); | |
| // make the LED pins outputs | |
| pinMode(yellowLed, OUTPUT); | |
| pinMode(redLed, OUTPUT); | |
| pinMode(greenLed, OUTPUT); | |
| // set the switch pin as an input | |
| pinMode(switchPin, INPUT); | |
| // start serial communication for debugging | |
| Serial.begin(9600); | |
| // turn the green LED on | |
| digitalWrite(greenLed, HIGH); | |
| // move the servo to the unlocked position | |
| myServo.write(0); | |
| // print status to the Serial Monitor | |
| Serial.println("the box is unlocked!"); | |
| } | |
| void loop() { | |
| // if the box is unlocked | |
| if (locked == false) { | |
| // read the value of the switch pin | |
| switchVal = digitalRead(switchPin); | |
| // if the button is pressed, lock the box | |
| if (switchVal == HIGH) { | |
| // set the locked variable to "true" | |
| locked = true; | |
| // change the status LEDs | |
| digitalWrite(greenLed, LOW); | |
| digitalWrite(redLed, HIGH); | |
| // move the servo to the locked position | |
| myServo.write(90); | |
| // print out status | |
| Serial.println("the box is locked!"); | |
| // wait for the servo to move into position | |
| delay(1000); | |
| } | |
| } | |
| // if the box is locked | |
| if (locked == true) { | |
| // check the value of the piezo | |
| knockVal = analogRead(piezo); | |
| // if there are not enough valid knocks | |
| if (numberOfKnocks < 3 && knockVal > 0) { | |
| // check to see if the knock is in range | |
| if (checkForKnock(knockVal) == true) { | |
| // increment the number of valid knocks | |
| numberOfKnocks++; | |
| } | |
| // print status of knocks | |
| Serial.print(3 - numberOfKnocks); | |
| Serial.println(" more knocks to go"); | |
| } | |
| // if there are three knocks | |
| if (numberOfKnocks >= 3) { | |
| // unlock the box | |
| locked = false; | |
| // move the servo to the unlocked position | |
| myServo.write(0); | |
| // wait for it to move | |
| delay(20); | |
| // change status LEDs | |
| digitalWrite(greenLed, HIGH); | |
| digitalWrite(redLed, LOW); | |
| Serial.println("the box is unlocked!"); | |
| numberOfKnocks = 0; | |
| } | |
| } | |
| } | |
| // this function checks to see if a detected knock is within max and min range | |
| bool checkForKnock(int value) { | |
| // if the value of the knock is greater than the minimum, and larger | |
| // than the maximum | |
| if (value > quietKnock && value < loudKnock) { | |
| // turn the status LED on | |
| digitalWrite(yellowLed, HIGH); | |
| delay(50); | |
| digitalWrite(yellowLed, LOW); | |
| // print out the status | |
| Serial.print("Valid knock of value "); | |
| Serial.println(value); | |
| // return true | |
| return true; | |
| } | |
| // if the knock is not within range | |
| else { | |
| // print status | |
| Serial.print("Bad knock value "); | |
| Serial.println(value); | |
| // return false | |
| return false; | |
| } | |
| } | |