Description
This is an Arduino-controlled incubator for chicken's eggs. Its purpose is to keep temperature and humidity at defined values, so that the eggs are incubated and the chicks finally hatch after some days. The Arduino constantly measures temperature and humidity. So the temperature and humidity in the incubator can be maintained. Okey, let's see how it works.
Components Required
| 1. | Arduino UNO | * 1 |
| 2. | DHT22 Temperature Sensor | * 1 |
| 3. | LCD Shield | * 1 |
| 4. | Linear Regulator(7805) | * 1 |
| 5. | Infineon IRFZ44N MOSFET | * 1 |
| 6. | PC Fan(12V, 12cm) | * 1 |
| 7. | Servomotor(MG996R) | * 1 |
| 8. | 12V Power Supply | * 1 |
| 9. | Jumper Wires | * 1 |
Circuit Diagram
Program
#include <SoftwareServo.h>
#include <LiquidCrystal.h>
#include <DHT.h>
#include <EEPROM.h>
// stty -F /dev/ttyACM0 115200 cs8 cread clocal -hupcl time 30 && tee incubator.log </dev/ttyACM0
#define WDT_TIMEOUT WDTO_8S // if defined, enable hardware watchdog
#define DHTPIN 3 // data pin of the DHT T/H sensor
#define T_OFFSET 0.9 // temperature sensor offset
#define FAN_PIN 2 // fan tacho signal pin
#define FAN_THRES 500 // fan alarm threshold
#define BEEPER A2 // pin where beeper is attached
#define BRIGHTNESS 10 // display brightness pin
#define HEATER A1 // heater MOSFET pin
#define DELAY 2000 // loop delay in ms
#define TS_ADDR 0 // temperature set point EEPROM address
#define HS_ADDR 4 // humidity set point EEPROM address
#define HC_ADDR 8 // humiditiy control mode EEPROM address
#define TI_RESET 1 // integral reset threshold, set integral to 0 when T error greater than this
#define HI_RESET 5 // integral reset threshold, set integral to 0 when H error greater than this
#define ALARM_T 2 // temperature alarm threshold, alert if T error greater than this
#define ALARM_H 8 // humidity alarm threshold, alert if H error greater than this
#define H_AUTO_THRES 3 // disable vent control in auto mode if H error < this
#define H_AUTO_COUNT 200 // disable for n cycles
#define HWAT 0.25 // holt winters parameters for temperature smoothing
#define HWBT 0.2
#define HWAH 0.7 // holt winters parameters for humidity smoothing
#define HWBH 0.5
#define A 0.005 // long average parameter
#define VENTCLOSED 80 // consider vent closed if under this angle
#define VENTOPENMS 480000L // open vent if closed longer
#define VENTRESETMS 600000L // reset vent after this time (>VENTOPENMS!)
SoftwareServo vent;
DHT dht(DHTPIN, DHT22);
LiquidCrystal lcd(8, 9, 4, 5, 6, 7);
#define RIGHT 16
#define UP 8
#define DOWN 4
#define LEFT 2
#define SELECT 1
#define NO_KEY 0
byte getKey() {
int key = analogRead(0);
if (key < 50) {
return RIGHT;
} else if (key < 150) {
return UP;
} else if (key < 300) {
return DOWN;
} else if (key < 500) {
return LEFT;
} else if (key < 800) {
return SELECT;
} else {
return NO_KEY;
}
}
void eeread(int address, int length, void* p) {
byte* b = (byte*)p;
for (int i = 0; i < length; i++) {
*b++ = EEPROM.read(address + i);
}
}
void eewrite(int address, int length, void* p) {
byte* b = (byte*)p;
for (int i = 0; i < length; i++) {
EEPROM.write(address + i, *b++);
}
}
void write_byte(int address, byte &value) {
eewrite(address, sizeof(value), &value);
}
byte read_byte(int address) {
byte value;
eeread(address, sizeof(value), &value);
return value;
}
void write_int(int address, int &value) {
eewrite(address, sizeof(value), &value);
}
int read_int(int address) {
int value;
eeread(address, sizeof(value), &value);
return value;
}
void write_float(int address, float &value) {
eewrite(address, sizeof(value), &value);
}
float read_float(int address) {
float value;
eeread(address, sizeof(value), &value);
return value;
}
void heater(boolean on) {
digitalWrite(HEATER, !on ? LOW : HIGH);
}
boolean heater() {
return digitalRead(HEATER) == HIGH;
}
volatile int fancount;
void count() {
++fancount;
}
void beep(unsigned long f, unsigned long l) {
pinMode(BEEPER, OUTPUT);
byte v = 0;
f = 500000 / f;
l = (1000 * l) / f;
for (int i = 0; i < l; ++i) {
digitalWrite(BEEPER, v = !v);
delayMicroseconds(f);
}
pinMode(BEEPER, INPUT);
}
float Ts, Hs; // set points
byte Hcontrol; // H control mode
byte Ts_changed, Hs_changed; // setpoint changed flags
float ET, dETdt, IETdt; // prop/diff/integ terms for T
float EH, dEHdt, IEHdt; // prop/diff/integ terms for H
float T, Tavg = NAN, Tvar, Tstd;
float H, Havg = NAN, Hvar, Hstd;
float Hpower, Hduty; // heater current power, average duty cycle
unsigned long t0, Hon, talarm, tventclosed;
byte displayMode;
byte key, bri = 255, alarm;
boolean ventclosed;
int fanrpm;
void setup() {
#if defined(WDT_TIMEOUT)
wdt_enable(WDT_TIMEOUT);
#endif
pinMode(HEATER, OUTPUT);
heater(0);
pinMode(BRIGHTNESS, OUTPUT);
analogWrite(BRIGHTNESS, bri = 255);
lcd.begin(16, 2);
lcd.noCursor();
lcd.print("Incubator 0.7");
lcd.setCursor(0, 1);
lcd.print(__DATE__);
dht.begin();
vent.setMinimumPulse(800);
vent.setMaximumPulse(2600);
vent.attach(11);
// write_float(TS_ADDR, Ts=37.8); write_float(HS_ADDR, Hs=55);
Ts = read_float(TS_ADDR);
Hs = read_float(HS_ADDR);
Hcontrol = read_byte(HC_ADDR);
pinMode(FAN_PIN, INPUT_PULLUP);
attachInterrupt(0, count, FALLING);
sei();
beep(800, 100);
beep(1000, 100);
beep(1200, 100);
beep(1600, 100);
}
void loop() {
unsigned long t1 = millis();
int dt = t1 - t0;
if (!key) {
key = getKey();
}
if (key) {
analogWrite(BRIGHTNESS, bri = 255);
}
if (t1 - Hon > Hpower * DELAY) {
heater(0);
}
if (Hcontrol && Hcontrol < H_AUTO_COUNT) {
vent.refresh();
}
if (alarm && !(alarm & 8)) {
beep(1000, 50);
beep(1414, 50);
}
if (dt > DELAY || key) {
if (!key) {
// beep(2000, 50);
T = dht.readTemperature() + T_OFFSET;
H = dht.readHumidity();
if ((isnan(T) || T < 10 || T > 60) || (Hcontrol && (isnan(H) || H < 5 || H > 95))) {
heater(0);
lcd.clear();
lcd.print("SENSOR ERROR!");
lcd.setCursor(0, 1);
lcd.print("T=");
lcd.print(T);
lcd.print("C H=");
lcd.print(H, 1);
lcd.print("%");
beep(2000, 1000);
return;
}
float dts = dt * 1e-3;
if (dt > DELAY) {
fanrpm = fancount * 60 / dts;
fancount = 0;
}
if (fanrpm < FAN_THRES) {
alarm |= 4;
} else {
alarm &= ~4;
}
// temperature Holt-Winters smoothing
float E0 = ET;
ET = HWAT * (T - Ts) + (1 - HWAT) * (ET + dETdt * dts); // smoothed T error (deviation from set point)
dETdt = HWBT * (ET - E0) / dts + (1 - HWBT) * dETdt; // smoothed derivative
IETdt += ET * dts; // integral of error
if (abs(ET) > TI_RESET) // reset integral on big deviation
IETdt = 0;
float pidT = 1.1765 * (ET + 0.010526 * IETdt + 23.75 * dETdt); // PID value, adjust coefficients to tune
Hpower = fanrpm > FAN_THRES ? max(0, min(1, -pidT)) : 0;
heater(Hpower > 0.1);
Hon = millis();
if (abs(ET) > ALARM_T) {
alarm |= 1;
vent.write(ET < 0 ? 0 : 180);
if (Hcontrol > 1) {
Hcontrol = 2;
}
} else {
alarm &= ~1;
}
// humidity Holt-Winters smoothing
E0 = EH;
EH = HWAH * (H - Hs) + (1 - HWAH) * (EH + dEHdt * dts); // smoothed H error (deviation from set point)
dEHdt = HWBH * (EH - E0) / dts + (1 - HWBH) * dEHdt; // smoothed derivative
IEHdt += EH * dts; // integral of error
if (abs(EH) > HI_RESET) // reset integral on big deviation
IEHdt = 0;
float pidH = 0.1176 * (EH + 0.09091 * IEHdt + 2.75 * dEHdt); // PID value, adjust coefficients to tune
vent.write(pidH * 180);
if (Hcontrol && abs(EH) > ALARM_H) {
alarm |= 2;
} else {
alarm &= ~2;
}
boolean ventclosed0 = ventclosed;
ventclosed = vent.read() < VENTCLOSED;
if (ventclosed && ventclosed != ventclosed0) {
tventclosed = millis();
}
boolean openvent = ventclosed && millis() - tventclosed > VENTOPENMS;
if (openvent) {
vent.write(180);
if (millis() - tventclosed > VENTRESETMS) {
tventclosed = millis();
}
}
if (Hcontrol > 1) {
if (abs(EH) > H_AUTO_THRES || openvent) {
Hcontrol = 2;
} else {
if (Hcontrol < H_AUTO_COUNT) {
++Hcontrol;
} else {
IEHdt = 0;
}
}
}
// long term averages
Tavg = A * T + (1 - A) * (isnan(Tavg) ? T : Tavg);
Tvar = A * pow(T - Tavg, 2) + (1 - A) * (isnan(Tvar) ? 0 : Tvar);
Tstd = sqrt(Tvar);
Havg = A * H + (1 - A) * (isnan(Havg) ? H : Havg);
Hvar = A * pow(H - Havg, 2) + (1 - A) * (isnan(Hvar) ? 0 : Hvar);
Hstd = sqrt(Hvar);
Hduty = A * Hpower + (1 - A) * Hduty;
if (Ts_changed) {
if (Ts_changed-- == 1)
write_float(TS_ADDR, Ts);
}
if (Hs_changed) {
if (Hs_changed-- == 1)
write_float(HS_ADDR, Hs);
}
}
if (key & SELECT) {
displayMode = ++displayMode % 8;
}
lcd.clear();
lcd.print("T=");
lcd.print(Ts + ET);
lcd.print("C H=");
lcd.print(Hs + EH, 1);
lcd.print("%");
lcd.setCursor(0, 1);
float uptime;
char unit;
switch (displayMode) {
case 0: // raw values
lcd.print("T=");
lcd.print(T);
lcd.print("C H=");
lcd.print(H, 1);
lcd.print("%");
break;
case 1: // temperature setpoint
if (key & (UP | DOWN | LEFT | RIGHT)) {
Ts = max(20, min(50, Ts + (key & (UP | RIGHT) ? +1 : -1) * (key & (UP | DOWN) ? 0.1 : 1)));
Ts_changed = 10;
}
lcd.print("Ts=");
lcd.print(Ts);
lcd.print("C");
break;
case 2: // humidity setpoint
if (key & (UP | DOWN)) {
Hs = max(10, min(90, Hs + (key & UP ? +1 : -1)));
Hs_changed = 10;
}
if (key & RIGHT) {
if (Hcontrol < 2) {
Hcontrol = ++Hcontrol;
} else {
Hcontrol = 0;
}
IEHdt = 0;
write_byte(HC_ADDR, Hcontrol);
}
lcd.print("Hs=");
lcd.print(Hs);
lcd.print("% ");
lcd.print(Hcontrol == 1 ? "on" : (Hcontrol > 1 ? "auto" : "off"));
break;
case 3: // average temperatur
lcd.print("Ta=");
lcd.print(Tavg);
lcd.print("C (");
lcd.print(Tstd);
lcd.print(")");
break;
case 4: // average humidity
lcd.print("Ha=");
lcd.print(Havg);
lcd.print("% (");
lcd.print(Hstd);
lcd.print(")");
break;
case 5: // heater duty cycle
lcd.print("Hd=");
lcd.print(Hduty);
lcd.print(" Hp=");
lcd.print(Hpower);
break;
case 6: // air vent
lcd.print("V=");
lcd.print(vent.read() / 180.0);
lcd.print(" F=");
lcd.print(fanrpm);
break;
case 7: // average humidity
uptime = t1 * 1e-3;
unit = 's';
if (uptime > 60) {
uptime /= 60;
unit = 'm';
if (uptime > 60) {
uptime /= 60;
unit = 'h';
if (uptime > 24) {
uptime /= 24;
unit = 'd';
}
}
}
lcd.print("Up=");
lcd.print(uptime, 1);
lcd.print(unit);
break;
default:;
}
if (alarm & 7) {
if (!talarm) {
talarm = millis();
}
// sound on persistent alarm and fan failure
if (millis() - talarm > 300000L || alarm & 4) {
alarm &= ~8;
}
analogWrite(BRIGHTNESS, bri = 255);
lcd.setCursor(0, 0);
if (alarm & 1)
lcd.print("T ");
if (alarm & 2)
lcd.print("H ");
if (alarm & 4)
lcd.print("F ");
lcd.print("ALARM! ");
if (!(alarm & 8) && key) {
alarm |= 8; // alarm acknowledged
talarm = millis();
}
if (!(alarm & 8)) {
lcd.setCursor(0, 1);
lcd.print("T=");
lcd.print(T);
lcd.print("C H=");
lcd.print(H, 1);
lcd.print("%");
}
} else {
alarm = 0;
talarm = 0;
}
if (key) {
delay((key & SELECT) ? 500 : 200);
}
if (bri) {
analogWrite(BRIGHTNESS, --bri);
}
key = 0;
t0 = t1;
}
#if defined(WDT_TIMEOUT)
wdt_reset();
#endif
}