I am facing issues while connecting the 5 sensors in the ardiuno uno

Projects General Guidance
1

I am making the project on the health care based one.
It as 10 - 12 sensors i tried to make the connections with the first 5 sensors but the problem is i am not able to get the output in the serial moniyor itself

And the another one is the gsm 900A module is working for some time and it is not working for some time

Anyone tell the better and the best broad for the connection with less complexity

Or any other shield broad can be used to ?
If tell the name of it
Pls

I am not able to get the ouput in the serail monitor
2

What are these sensors?

3

Post the sketch, connection and wiring diagramm and datasheets of sensors used to see how we can help.

4

Your other topic on the same subject deleted.

Please do not duplicate your questions as doing so wastes the time and effort of the volunteers trying to help you as they are then answering the same thing in different places.

Please create one topic only for your question and choose the forum category carefully. If you have multiple questions about the same project then please ask your questions in the one topic as the answers to one question provide useful context for the others, and also you won’t have to keep explaining your project repeatedly.

Repeated duplicate posting could result in a temporary or permanent ban from the forum.

Could you take a few moments to Learn How To Use The Forum

It will help you get the best out of the forum in the future.

Thank you.

5

If any sensor is connected to Uno pins 0 or 1, they may interfere with Serial Monitor.

6

You have posted in the Project Hub category of the forum. Was that deliberate and what programming environment are you using ?

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Step-by-Step: Connecting 5 Sensors to Arduino Uno

:electric_plug: 1. Know Your Sensors

Let’s first clarify:

  • What kind of sensors are you using? (e.g., DHT11, Ultrasonic HC-SR04, IR sensor, Light sensor, etc.)
  • Are they digital, analog, or using I2C/SPI?

The Uno has:

  • 6 Analog pins (A0–A5)
  • 14 Digital I/O pins (0–13)
  • Shared I2C pins (A4 = SDA, A5 = SCL)
  • Shared SPI pins (10–13)

:wrench: 2. Assign Pins

Make sure each sensor has its own pin (unless using I2C/SPI, which can share).

Example:

Sensor Type Arduino Pin
DHT11 (Temp+Humidity) Digital D2
Ultrasonic (HC-SR04) Digital D3 (Trig), D4 (Echo)
IR Sensor Digital D5
LDR Analog A0
Gas Sensor (MQ2) Analog A1

:warning: 3. Common Issues

Issue Fix
Not enough power Use external 5V supply if sensors draw too much current.
Incorrect pins Double-check pin numbers in code and wiring.
Code conflicts Avoid delays or blocking functions that interfere with sensor readings.
Missing libraries Install the correct libraries (e.g., DHT.h for DHT11).
Floating inputs Use pull-up/down resistors if needed.
Sensor not responding Check baud rate, serial monitor, and use test code per sensor.

:light_bulb: Sample Code for Multiple Sensors (Simplified)

cpp

CopyEdit

#include <DHT.h>
#define DHTPIN 2
#define DHTTYPE DHT11
DHT dht(DHTPIN, DHTTYPE);

const int irPin = 5;
const int ldrPin = A0;
const int gasPin = A1;

void setup() {
  Serial.begin(9600);
  dht.begin();
  pinMode(irPin, INPUT);
}

void loop() {
  float temp = dht.readTemperature();
  int irVal = digitalRead(irPin);
  int ldrVal = analogRead(ldrPin);
  int gasVal = analogRead(gasPin);

  Serial.print("Temp: "); Serial.print(temp);
  Serial.print(" | IR: "); Serial.print(irVal);
  Serial.print(" | LDR: "); Serial.print(ldrVal);
  Serial.print(" | Gas: "); Serial.println(gasVal);

  delay(1000);
}

:hammer_and_wrench: Still Not Working?

Please tell me:

  • What are the 5 sensors you are using?
  • Are you getting any error messages?
  • Is the code uploading successfully?
  • Are you using the Serial Monitor to debug?
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