I2c scanner prints I and sht20 not working

im trying to use sht20 sensor for my project but it only works sometimes and not consistently sometimes it will and then the serial monitor will not work and freeze. i tried to use i2c scanner but it only prints I

// --------------------------------------
// i2c_scanner
//
// Version 1
//    This program (or code that looks like it)
//    can be found in many places.
//    For example on the Arduino.cc forum.
//    The original author is not know.
// Version 2, Juni 2012, Using Arduino 1.0.1
//     Adapted to be as simple as possible by Arduino.cc user Krodal
// Version 3, Feb 26  2013
//    V3 by louarnold
// Version 4, March 3, 2013, Using Arduino 1.0.3
//    by Arduino.cc user Krodal.
//    Changes by louarnold removed.
//    Scanning addresses changed from 0...127 to 1...119,
//    according to the i2c scanner by Nick Gammon
//    https://www.gammon.com.au/forum/?id=10896
// Version 5, March 28, 2013
//    As version 4, but address scans now to 127.
//    A sensor seems to use address 120.
// Version 6, November 27, 2015.
//    Added waiting for the Leonardo serial communication.
// 
//
// This sketch tests the standard 7-bit addresses
// Devices with higher bit address might not be seen properly.
//

#include <Wire.h>


void setup()
{
  Wire.begin();

  Serial.begin(9600);
  while (!Serial);             // Leonardo: wait for serial monitor
  Serial.println("\nI2C Scanner");
}


void loop()
{
  byte error, address;
  int nDevices;

  Serial.println("Scanning...");

  nDevices = 0;
  for(address = 1; address < 127; address++ ) 
  {
    // The i2c_scanner uses the return value of
    // the Write.endTransmisstion to see if
    // a device did acknowledge to the address.
    Wire.beginTransmission(address);
    error = Wire.endTransmission();

    if (error == 0)
    {
      Serial.print("I2C device found at address 0x");
      if (address<16) 
        Serial.print("0");
      Serial.print(address,HEX);
      Serial.println("  !");

      nDevices++;
    }
    else if (error==4) 
    {
      Serial.print("Unknown error at address 0x");
      if (address<16) 
        Serial.print("0");
      Serial.println(address,HEX);
    }    
  }
  if (nDevices == 0)
    Serial.println("No I2C devices found\n");
  else
    Serial.println("done\n");

  delay(5000);           // wait 5 seconds for next scan
}```

this is the code for I2C scanner 

```/*!
 * @file  DFRobot_SHT20_test.ino
 * @brief DFRobot's SHT20 Humidity And Temperature Sensor Module
 * @n     This example demonstrates how to read the user registers to display resolution and other settings.
 *        Uses the SHT20 library to display the current humidity and temperature.
 *        Open serial monitor at 9600 baud to see readings.
 *        Errors 998 if not sensor is detected. Error 999 if CRC is bad.
 * Hardware Connections:
 * -VCC = 3.3V
 * -GND = GND
 * -SDA = A4 (use inline 330 ohm resistor if your board is 5V)
 * -SCL = A5 (use inline 330 ohm resistor if your board is 5V)
 */
 

#include <Wire.h>

#include <DFRobot_SHT20.h>

DFRobot_SHT20    sht20;

void setup()
{
    Serial.begin(9600);
    Serial.println("SHT20 Example!");
    sht20.initSHT20();                                  // Init SHT20 Sensor
    delay(10000);
    sht20.checkSHT20();                                 // Check SHT20 Sensor
}

void loop()
{
    float humd = sht20.readHumidity();                  // Read Humidity
    float temp = sht20.readTemperature();               // Read Temperature
    Serial.print("Time:");
    Serial.print(millis());
    Serial.print(" Temperature:");
    Serial.print(temp, 1);
    Serial.print("C");
    Serial.print(" Humidity:");
    Serial.print(humd, 1);
    Serial.print("%");
    Serial.println();
    delay(1000);
}

this is the code i tried to use on the sht20 program.

if anyone have an idea what "I" means or how to check if my sensor is fried please inform me, it will be much appreciated.

the result of the sht20 program only prints

SHT20 Example!

it does not print the word temperature and Humidity


Hi,
Is your SHT20 mounted on a module?
Are there pullup resistors on the SCL and SDA pins?
Which arduino are you using?
Did you run scanner.ino?
This sensor cannot be powered with a voltage greater than 3.3V.
If you feed with higher voltage it will be damaged.

Which Arduino board do you have ?
Try a better USB cable.

Arduino nano is the board im using.



The sht20 im using is already in a case so i cant see if it has module but the store have spec that it can work from 2.4 - 5.5 voltage.

I have tried it, i also post the code but im not sure i did it right, when i run it and use the serial monitor it prints only "I". I also include an image

You seem to have more than one problem.

If you upload a sketch that blinks the led or a sketch that shows messages to the Serial Monitor. Do they run 100% okay ?

Can you give a link to where you bought that sensor ?
They put SDA next to SCL in a cable, that is not nice.
It is unclear if you have to add pullup resistors for SDA and SCL.

The Senserion SHT20 runs at 3.3V (2.1 ... 3.6). Its absolute maximum is 5V, but then the sensor gets damaged after a while.
I wonder if there is a voltage regulator in the probe.

Is it this one ? https://www.dfrobot.com/product-1636.html
I can not find information of what is inside the probe.

If you want something that works, then buy something from Adafruit: https://www.adafruit.com/category/66

https://s.lazada.com.ph/s.T0871 this is the link on where i bought the sensor, i will try do disassemble the probe now to check if it has pull up resistors

Just add 10K pullups and see what happens. if it has them pullups already, 10K won't hurt anything.
If it does not have pullups then you should see some change in performance.

Tom... :smiley: :+1: :coffee: :australia:

Do you have a multimeter ? (also called a DMM).

If you power it with 5V and don't connect the SDA and SCL wires, what is the voltage of the SDA and SCL wires from the sensor ?
Do you have resistors ? I think you need extra pullup resistors.

You would need resistors and a multimeter and electronics knowledge, to try to figure out what is inside the probe. My guess is that it is just the SHT20, and nothing else. That means it is meant for a 3.3V Arduino board and you need to add pullup resistors to 3.3V.

They have SDA next to SCL, and the cable is 1 meter long. There might be too much crosstalk between SDA and SCL.

Can you make a photo of your project ? Do you use a breadboard ?

I have a multimeter here, and i will try your suggestion, i also have a resistors, i will post pictures after :blush::blush::blush:

Heyyy tom i will try to put resistors on the sht20, thanks for the suggestion :grin::coffee::philippines:

Good day i have tried your suggestion and it work but sadly it has the same problem as this

we have the same result. it must be that the 5v and no resistor damage the sensor. thank you for assisting. i will purchase a new sensor :cry:

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