Garage door controller

1// Universal Garage door control system made with an Arduino Nano microcontroller. 
2// Originally developed for a Wayne Dalton garage door with a ecostar electric lift mechanism
3// The door movement is controlled by a single pushbutton and limited by two limit switches.
4// The door can be stopped mid-movement with the button, and its movement direction can also be changed anytime.
5// This code includes safety functions to protect the motor and handle error cases.
6// DURING THE FIRST TEST MAKE SURE THAT THE DOOR IS ACTUALLY MOVING IN THE SAME DIRECTION AS THE CODE "THINKS" !!!!
7// IF NOT, SWITCH THE POLARITY OF THE WIRES GOING TO THE MOTOR.
8
9// Pins
10const int button = 5; 
11const int lowerLimit = 2;
12const int upperLimit = 11;
13const int relay1 = 8;
14const int relay2 = 7;
15const int currentSensor = A0;
16
17// Constants
18const int requiredPressTime = 500;
19const int maxMoveTime = 18000;       // Change to match the movement time of your door
20const int upperMoveExtra = 6000;     // Extra "puffer" because door moves slower when going up
21const int pressed = LOW;
22const int atBottom = LOW;
23const int atTop = LOW;
24const int maxCurrent = 5;            // Change to fit your door
25const float sensitivity = 0.066;     // (0.066 for 30A sensor), (0.100 for 20A), (0.185 for 5A)
26const int measurmentInterval = 500;  // Time difference between current readings
27const int numReadings = 1000;        // Number of readings used to calibrate zero current voltage
28
29// Variables
30String lastDirection = "stopped";
31String currentMovement = "stopped";
32int previousState = HIGH;
33int currentOverCounter = 0;
34unsigned long pressMoment = 0;
35unsigned long movementStartTime = 0;
36unsigned long previousMillis = 0;
37float zeroCurrentVoltage = 0.0;
38
39void setup() {
40
41  // Pin modes
42  pinMode(relay1, OUTPUT);
43  pinMode(relay2, OUTPUT);
44  pinMode(button, INPUT_PULLUP);
45  pinMode(lowerLimit, INPUT_PULLUP);
46  pinMode(upperLimit, INPUT_PULLUP);
47
48  // Relays initially off
49  digitalWrite(relay1, HIGH); 
50  digitalWrite(relay2, HIGH); 
51
52  zeroCurrentVoltage = calibrateZeroCurrentVoltage();
53}
54
55
56// Calibrates the zero-current voltage to account for sensor offsets
57float calibrateZeroCurrentVoltage() {
58
59  long sum = 0;
60
61  // Calculates the sum of 1000 measurments
62  for (int i = 0; i < numReadings; i++) {
63    sum += analogRead(currentSensor);
64    delay(1);
65  }
66  
67  float averageReading = sum / numReadings;
68  float zeroVoltage = averageReading * (5.0 / 1023.0);
69  return zeroVoltage;
70}
71
72
73void moveUp() {
74  lastDirection = "up";
75  currentMovement = "up";
76  movementStartTime = millis();
77  digitalWrite(relay1, LOW);
78  digitalWrite(relay2, HIGH);
79}
80
81
82void moveDown() {
83  lastDirection = "down";
84  currentMovement = "down";
85  movementStartTime = millis();
86  digitalWrite(relay1, HIGH);
87  digitalWrite(relay2, LOW);  
88}
89
90
91void stop() {
92  currentMovement = "stopped";
93  movementStartTime = 0;
94  digitalWrite(relay1, HIGH);
95  digitalWrite(relay2, HIGH);
96}
97
98
99// Reads if the button has been pressed for the specified time and returns LOW if it has.
100// This could be replaced by a simple digitalRead in the loop, but I decided to go this route because
101// significant interference caused by fluorescent lights in the garage sometimes caused the door to open by itself.
102int readButton() {
103
104  int buttonStatus = digitalRead(button);
105
106  // If the button is pressed and the state has changed.
107  if (buttonStatus == pressed && buttonStatus != previousState) {
108    pressMoment = millis(); 
109    previousState = buttonStatus;
110  }
111
112  // If the button is released and the state has changed.
113  else if (buttonStatus != pressed && buttonStatus != previousState) {
114    previousState = buttonStatus; 
115    pressMoment = 0;
116  }
117
118  // Returns LOW if the button has been pressed for the specified time.
119  if (pressMoment > 0 && (millis() - pressMoment >= requiredPressTime) && buttonStatus == pressed) {
120    pressMoment = 0;
121    return pressed;
122  } 
123  return HIGH; 
124}
125
126
127void intermediatePosition() {
128  // If the button is pressed while the door is moving, the door stops
129  if (currentMovement != "stopped") {                                                         
130    stop();
131  }
132  else {
133    // If the door was stopped while moving up, it starts moving down when button is pressed
134    if (lastDirection == "up") {                                             
135      moveDown();
136    }
137    // If the door was stopped while moving down, it starts moving up when button is pressed
138    // The door also starts moving up when the button is pressed if the system is powered on while the door is in an intermediate position.
139    else if (lastDirection == "stopped" || lastDirection == "down") {
140      moveUp();
141    }
142  }
143}
144
145
146// Prevents motor movement and possible damage in case of a malfunction.
147// Stops the motor if one of the limit switches is stuck.
148// Stops the motor if it has been running for more than the specified time. 
149// Has different times for up and down movement because of speed difference.
150void malfunctionProtection(){
151
152  // Stops the door if both limit switches are pressed at the same time.
153  if (digitalRead(lowerLimit) == atBottom && digitalRead(upperLimit) == atTop){
154    stop();
155  }
156  // Limits the door's upward movement time.
157  else if (currentMovement == "up" && (millis() - movementStartTime > maxMoveTime + upperMoveExtra)){
158    stop();
159  }
160  // Limits the door's downward movement time.
161  else if (currentMovement == "down" && (millis() - movementStartTime > maxMoveTime)){
162    stop();
163  }
164}
165
166
167// Protects the motor by measuring the current and stopping it if a set current is exceeded for a set time
168void checkCurrent() {
169
170  unsigned long currentMillis = millis();
171
172  // Checks if the time since the last measurement exceeds the defined interval
173  if (currentMillis - previousMillis >= measurmentInterval) {
174
175    previousMillis = currentMillis;
176    int analogValue = analogRead(currentSensor);
177    
178    // Converts the analog sensor reading to voltage
179    float sensorVoltage = analogValue * (5.0 / 1023.0);
180    
181    // Converts voltage to current
182    float current = (sensorVoltage - zeroCurrentVoltage) / sensitivity;
183
184    // If the motor has been running for more than 2 seconds and the current exceeds the maximum allowed, updates counter
185    if(millis() - movementStartTime > 2000 && abs(current) > maxCurrent){
186      currentOverCounter += 1;
187    }
188    else{
189      currentOverCounter = 0;  // Reset the counter if no overcurrent condition
190    }
191  }
192
193  // Stops the motor if the overcurrent condition persists for two consecutive intervals
194  if(currentOverCounter >= 2){
195    stop();
196  }
197}
198
199
200void loop()  {
201
202  int buttonState = readButton();
203  int lowerLimitState = digitalRead(lowerLimit);
204  int upperLimitState = digitalRead(upperLimit);
205  malfunctionProtection();
206  checkCurrent();
207
208  // The door stops when it is at the top
209  if (currentMovement == "up" && upperLimitState == atTop){
210    stop();
211  }
212  // The door stops when it is at the bottom
213  else if (currentMovement == "down" && lowerLimitState == atBottom){                                                   
214    stop();
215  }
216
217  // If the door is at the bottom when the button is pressed, it starts moving up
218  if (buttonState == pressed && lowerLimitState == atBottom){
219    moveUp();   
220  }
221
222  // If the door is at the top when the button is pressed, it starts moving down
223  else if (buttonState == pressed && upperLimitState == atTop) {                                                           
224    moveDown();
225  }
226
227  // If the button is pressed when the door is in an intermediate position
228  else if (buttonState == pressed && upperLimitState != atTop && lowerLimitState != atBottom) {
229    intermediatePosition();
230  }
231}