hi guys , i have a project with 8 sensors connected with arduino nano and the nine one is servo mg996r , when i run my code the servo starts moving in strange way and not as required of it and its main task in the project , anyone knows why?
this is my code :
#include <Wire.h>
#include <Adafruit_Sensor.h>
#include <DHT.h>
#include <DHT_U.h>
#include <MPU6050_light.h>
#include <HX711.h>
#include <Servo.h>
#include <SoftwareSerial.h>
#include <TinyGPS++.h>
// ==== Pins ====
#define LDR_PIN A0
#define SERVO_PIN 9
#define DHT_PIN 2
#define DHT_TYPE DHT22
#define SCALE_DT 6
#define SCALE_SCK 5
#define GPS_RX 4
#define GPS_TX 3
#define LED_OK 11
#define LED_ERR 12
#define BUZZER 10
// ==== Objects ====
Servo servo;
DHT dht(DHT_PIN, DHT_TYPE);
MPU6050 mpu(Wire);
HX711 scale;
SoftwareSerial gpsSerial(GPS_RX, GPS_TX);
TinyGPSPlus gps;
// ==== Thresholds ====
const int lightThresh = 300;
const float tempMin = 30.0, tempMax = 38.0;
const float humMin = 45.0, humMax = 75.0;
const float mpuThresh = 0.5;
const float theftRadius = 100.0;
const float originLat = 32.411438;
const float originLng = 35.341606;
// ==== States ====
bool manualMode = false;
bool doorOpen = false;
bool alertActive = false;
bool redState = false;
bool servoMoving = false;
// ==== Sensor Readings ====
float temp = 0, hum = 0;
float accX = 0, accY = 0, accZ = 1;
float weight = 0;
float lat = 0, lng = 0, dist = 0;
int lightVal = 0;
// ==== Servo Control ====
int servoPos = 0, targetPos = 0;
unsigned long lastServoMs = 0;
const int servoDelay = 15;
// ==== Timing ====
unsigned long tLdr = 0, tDht = 0, tMpu = 0, tWeight = 0, tGps = 0, tPrint = 0, tBlink = 0;
const unsigned long iLdr = 1000, iDht = 3000, iMpu = 500, iWeight = 3000, iGps = 1000, iPrint = 1000;
String cmd = "", reason = "";
void setup() {
Serial.begin(9600);
gpsSerial.begin(9600);
servo.attach(SERVO_PIN);
servo.write(servoPos);
dht.begin();
Wire.begin();
mpu.begin();
mpu.calcOffsets(true, true);
scale.begin(SCALE_DT, SCALE_SCK);
scale.set_scale(27.2);
scale.tare();
pinMode(LED_OK, OUTPUT);
pinMode(LED_ERR, OUTPUT);
pinMode(BUZZER, OUTPUT);
digitalWrite(LED_OK, HIGH);
Serial.println("Ready.");
}
void loop() {
unsigned long now = millis();
updateGPS();
handleCmd();
moveServo();
if (!manualMode && !servoMoving && now - tLdr >= iLdr) {
tLdr = now;
lightVal = analogRead(LDR_PIN);
controlDoor();
}
if (now - tDht >= iDht) {
tDht = now;
temp = dht.readTemperature();
hum = dht.readHumidity();
}
if (now - tMpu >= iMpu) {
tMpu = now;
mpu.update();
accX = mpu.getAccX();
accY = mpu.getAccY();
accZ = mpu.getAccZ();
}
if (now - tWeight >= iWeight) {
tWeight = now;
weight = scale.get_units(4);
}
alertCheck();
if (now - tPrint >= iPrint) {
tPrint = now;
printData();
}
}
void updateGPS() {
while (gpsSerial.available()) gps.encode(gpsSerial.read());
if (millis() - tGps >= iGps && gps.location.isUpdated()) {
tGps = millis();
lat = gps.location.lat();
lng = gps.location.lng();
}
}
void handleCmd() {
if (Serial.available()) {
cmd = Serial.readStringUntil('\n');
cmd.trim();
if (cmd == "open") { startServo(servoPos, 90); doorOpen = true; manualMode = true; }
if (cmd == "close") { startServo(servoPos, 0); doorOpen = false; manualMode = true; }
if (cmd == "auto") manualMode = false;
}
}
void startServo(int from, int to) {
servoPos = from;
targetPos = to;
servoMoving = true;
lastServoMs = millis();
}
void moveServo() {
if (servoMoving && millis() - lastServoMs >= servoDelay) {
lastServoMs = millis();
if (servoPos < targetPos) servoPos++;
else if (servoPos > targetPos) servoPos--;
else servoMoving = false;
servo.write(servoPos);
}
}
void controlDoor() {
if (lightVal > lightThresh && !doorOpen) {
startServo(servoPos, 90);
doorOpen = true;
} else if (lightVal <= lightThresh && doorOpen) {
startServo(servoPos, 0);
doorOpen = false;
}
}
void alertCheck() {
bool dhtOk = !isnan(temp) && !isnan(hum);
bool fall = accZ < 0.5;
bool tilt = abs(accX) > mpuThresh || abs(accY) > mpuThresh;
bool tempA = dhtOk && (temp < tempMin || temp > tempMax);
bool humA = dhtOk && (hum < humMin || hum > humMax);
dist = calcDist(lat, lng, originLat, originLng);
bool theft = dist > theftRadius;
alertActive = fall || tilt || tempA || humA || theft;
reason = "";
if (fall) reason += "Fall,";
if (tilt) reason += "Tilt,";
if (tempA) reason += "Temp,";
if (humA) reason += "Humidity,";
if (theft) reason += "Theft,";
if (reason.endsWith(",")) reason.remove(reason.length() - 1);
if (alertActive) {
if (millis() - tBlink > 500) {
tBlink = millis();
redState = !redState;
digitalWrite(LED_ERR, redState);
digitalWrite(BUZZER, redState);
}
digitalWrite(LED_OK, LOW);
} else {
digitalWrite(LED_ERR, LOW);
digitalWrite(BUZZER, LOW);
digitalWrite(LED_OK, HIGH);
}
}
void printData() {
Serial.print("{");
Serial.print("\"temp\":" + String(temp) + ",");
Serial.print("\"hum\":" + String(hum) + ",");
Serial.print("\"accX\":" + String(accX) + ",");
Serial.print("\"accY\":" + String(accY) + ",");
Serial.print("\"accZ\":" + String(accZ) + ",");
Serial.print("\"weight\":" + String(weight) + ",");
Serial.print("\"light\":" + String(lightVal) + ",");
Serial.print("\"door\":\"" + String(doorOpen ? "open" : "closed") + "\",");
Serial.print("\"alert\":" + String(alertActive ? "true" : "false") + ",");
Serial.print("\"reason\":\"" + reason + "\",");
Serial.print("\"lat\":" + String(lat, 6) + ",");
Serial.print("\"lng\":" + String(lng, 6));
Serial.println("}");
}
float calcDist(float lat1, float lon1, float lat2, float lon2) {
const float R = 6371000;
float dLat = radians(lat2 - lat1);
float dLon = radians(lon2 - lon1);
float a = sin(dLat / 2) * sin(dLat / 2) +
cos(radians(lat1)) * cos(radians(lat2)) *
sin(dLon / 2) * sin(dLon / 2);
float c = 2 * atan2(sqrt(a), sqrt(1 - a));
return R * c;
}
