Arnov Sharma
Published © MIT

ROOM TEMP Meter with Arduino Nano and AHT10

A simple TEMP and Humidity Meter with simple Arduino Nano and SSD1306 with AHT10 Sensor.

BeginnerFull instructions provided1 hour771
ROOM TEMP Meter with Arduino Nano and AHT10

Things used in this project

Hardware components

AHT10 Sensor
×1
Arduino Nano R3
Arduino Nano R3
×1
PCBWay Custom PCB
PCBWay Custom PCB
×1

Story

Read more

Schematics

sch

Code

code

C/C++
#include <Wire.h>
#include <AHTxx.h>

#include <Adafruit_SSD1306.h>
#include <Adafruit_GFX.h>

#define OLED_WIDTH 128
#define OLED_HEIGHT 64

#define OLED_ADDR   0x3C
Adafruit_SSD1306 display(OLED_WIDTH, OLED_HEIGHT);



float ahtValue;                               //to store T/RH result

AHTxx aht10(AHTXX_ADDRESS_X38, AHT1x_SENSOR); //sensor address, sensor type


void setup()
{
  #if defined(ESP8266)
  WiFi.persistent(false);  //disable saving wifi config into SDK flash area
  WiFi.forceSleepBegin();  //disable AP & station by calling "WiFi.mode(WIFI_OFF)" & put modem to sleep
  #endif

  display.begin(SSD1306_SWITCHCAPVCC, OLED_ADDR);
  display.clearDisplay();

  Serial.begin(115200);
  Serial.println();
  
  while (aht10.begin() != true) //for ESP-01 use aht10.begin(0, 2);
  {
    Serial.println(F("AHT1x not connected or fail to load calibration coefficient")); //(F()) save string to flash & keeps dynamic memory free

    delay(5000);
  }

  Serial.println(F("AHT10 OK"));

  //Wire.setClock(400000); //experimental I2C speed! 400KHz, default 100KHz
}


void loop()
{
  /* DEMO - 1, every temperature or humidity call will read 6-bytes over I2C, total 12-bytes */
  Serial.println();
  Serial.println(F("DEMO 1: read 12-bytes"));

  ahtValue = aht10.readTemperature(); //read 6-bytes via I2C, takes 80 milliseconds

  display.clearDisplay();
  display.setTextSize(2);
  display.setTextColor(WHITE);
  display.setCursor(30, 0);
  display.println(F("Temp-"));

//  Serial.print(F("Temperature...: "));
  
  if (ahtValue != AHTXX_ERROR) //AHTXX_ERROR = 255, library returns 255 if error occurs
  {

  display.setTextSize(2);
  display.setTextColor(WHITE);
  display.setCursor(35, 25);
  display.println(ahtValue);
  display.display();
//    Serial.print(ahtValue);
   
  }
  else
  {
    printStatus(); //print temperature command status

    if   (aht10.softReset() == true) Serial.println(F("reset success")); //as the last chance to make it alive
    else                             Serial.println(F("reset failed"));
  }

  delay(2000); //measurement with high frequency leads to heating of the sensor, see NOTE

  ahtValue = aht10.readHumidity(); //read another 6-bytes via I2C, takes 80 milliseconds

  display.clearDisplay();
  display.setTextSize(2);
  display.setTextColor(WHITE);
  display.setCursor(30, 0);
  display.println(F("Humd-"));
  
  
//  Serial.print(F("Humd-"));
  
  if (ahtValue != AHTXX_ERROR) //AHTXX_ERROR = 255, library returns 255 if error occurs
  {

  display.setTextSize(2);
  display.setTextColor(WHITE);
  display.setCursor(35, 25);
  display.println(ahtValue);
  display.display();
    
    
 //   Serial.println(F(" +-2%"));
  }
  else
  {
    printStatus(); //print humidity command status
  }

  delay(2000); //measurement with high frequency leads to heating of the sensor, see NOTE

  /* DEMO - 2, temperature call will read 6-bytes via I2C, humidity will use same 6-bytes */
  Serial.println();
  Serial.println(F("DEMO 2: read 6-byte"));

  ahtValue = aht10.readTemperature(); //read 6-bytes via I2C, takes 80 milliseconds

  Serial.print(F("Temperature: "));
  
  if (ahtValue != AHTXX_ERROR) //AHTXX_ERROR = 255, library returns 255 if error occurs
  {
    Serial.print(ahtValue);
    Serial.println(F(" +-0.3C"));
  }
  else
  {
    printStatus(); //print temperature command status
  }

  ahtValue = aht10.readHumidity(AHTXX_USE_READ_DATA); //use 6-bytes from temperature reading, takes zero milliseconds!!!

  Serial.print(F("Humidity...: "));
  
  if (ahtValue != AHTXX_ERROR) //AHTXX_ERROR = 255, library returns 255 if error occurs
  {
    Serial.print(ahtValue);
    Serial.println(F(" +-2%"));
  }
  else
  {
    printStatus(); //print temperature command status not humidity!!! RH measurement use same 6-bytes from T measurement
  }

  delay(10000); //recomended polling frequency 8sec..30sec
}

void printStatus()
{
  switch (aht10.getStatus())
  {
    case AHTXX_NO_ERROR:
      Serial.println(F("no error"));
      break;

    case AHTXX_BUSY_ERROR:
      Serial.println(F("sensor busy, increase polling time"));
      break;

    case AHTXX_ACK_ERROR:
      Serial.println(F("sensor didn't return ACK, not connected, broken, long wires (reduce speed), bus locked by slave (increase stretch limit)"));
      break;

    case AHTXX_DATA_ERROR:
      Serial.println(F("received data smaller than expected, not connected, broken, long wires (reduce speed), bus locked by slave (increase stretch limit)"));
      break;

    case AHTXX_CRC8_ERROR:
      Serial.println(F("computed CRC8 not match received CRC8, this feature supported only by AHT2x sensors"));
      break;

    default:
      Serial.println(F("unknown status"));    
      break;
  }
}

Credits

Arnov Sharma

Arnov Sharma

278 projects • 291 followers
Just your average MAKER

Comments