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AM2320 temperature and humidity sensor and ESP32 example

by shedboy71

Temperature and humidity combined sensor AM2320 digital temperature and humidity sensor is a digital signal output has been calibrated. Using special temperature and humidity acquisition technology, ensure that the product has a very high reliability and excellent long-term stability. Sensor consists of a capacitive moisture element and an integrated high-precision temperature measurement devices, and connected with a high-performance microprocessor .

AM2320 communication using a single bus, two communication modes standard I2C. Standard single-bus interface, the system integration becomes easy and quick. Ultra-small size, low power consumption, signal transmission distance up to 20 meters, making all kinds of applications and even the most demanding applications the best choice. I2C communication using standard communication sequence, the user can directly linked to the I2C communication bus without additional wiring, simple to use.

Two communication modes are used as humidity, temperature, and other digital information directly CRC checksum temperature-compensated output, users do not need to calculate the secondary digital output, and no need for temperature compensation of the humidity, temperature and humidity can be accurately information. Two communication modes are free to switch, the user can freely choose, easy to use, wide range of applications.

Specifications

• Operating Voltage: 3.1 VDC to 5.5 VDC
• Operating Temperature Range: -40 ° C to + 80 ° C
• Humidity Range: 0 to 99.9% RH
• Accuracy ( 25 ° C environment)
Temperature: ± 0.5 ° C
Humidity: ± 3%
• RH (10 … 90% RH)
Resolution: Temperature: 0.1 ° C
Resolution: Humidity: 0.1% RH
• Attenuation values
Temperature: <0.1 ℃ / Year
Humidity: <1% RH / Year
• Response time: Temperature: 5s
• Response Time: Humidity: 5s 1 / e (63%)
• Output signal: single bus / IIC signal
• Housing material: PC plastic

 

Parts List

Name Link
ESP32
AM2302
Connecting cables

Layout

AM2302 sensor ESP32 – Wemos Lolin32
SDA 21 (SDA)
SCL 22 (SCL)
+ 3v3
– GND

 

Code

I used this library – https://github.com/EngDial/AM2320

 

#include <AM2320.h>

AM2320 th(&Wire);

void setup() {
  Serial.begin(9600);
  Wire.begin();
}

void loop() {
  Serial.println(F("Chip = AM2320"));
  switch(th.Read()) {
    case 2:
      Serial.println(F("  CRC failed"));
      break;
    case 1:
      Serial.println(F("  Sensor offline"));
      break;
    case 0:
      Serial.print(F("  Humidity = "));
      Serial.print(th.Humidity);
      Serial.println(F("%"));
      Serial.print(F("  Temperature = "));
      Serial.print(th.cTemp);
      Serial.println(F("*C"));
      Serial.println();
      break;
  }
  delay(2000);
}

 

Output

Open the serial monitor

Chip = AM2320
Humidity = 49.10%
Temperature = 22.50*C

Chip = AM2320
Humidity = 49.20%
Temperature = 22.50*C

Chip = AM2320
Humidity = 49.10%
Temperature = 22.50*C

Links

 

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Code

ESP32 and SHT20 temperature sensor example

by shedboy71

In this example we will connect a SHT20 temperature sensor to an ESP32.

Lets look at the SHT20 sensor

The SHT20 humidity and temperature sensor of Sensirion has become an industry standard in terms of form factor and intelligence: Embedded in a reflow solderable Dual Flat No leads (DFN) package of 3 x 3mm foot print and 1.1mm height it provides calibrated, linearized sensor signals in digital, I2C format.

The SHT2x sensors contain a capacitive type humidity sensor, a band gap temperature sensor and specialized analog and digital integrated circuit – all on a single CMOSens® chip. This yields in an unmatched sensor performance in terms of accuracy and stability as well as minimal power consumption.

Every sensor is individually calibrated and tested. Lot identification is printed on the sensor and an electronic identification code is stored on the chip – which can be read out by command. Furthermore, the resolution of SHT2 can be changed by command (8/12bit up to 12/14bit for RH/T) and a checksum helps to improve communication reliability.

 

Parts List

Name Link
ESP32
SHT20
Connecting cables

 

Schematics

Couldn't find a good part for fritzing

Its an I2C device that needs 3.3v and GND, so its not that difficult to wire

 

Code

There is a library to make things easy and it is – https://github.com/DFRobot/DFRobot_SHT20

#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(100);
sht20.checkSHT20(); // Check SHT20 Sensor
}

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

 

Output

Open the serial monitor and you should see something similar to this

SHT20 Example!
End of battery: no
Heater enabled: no
Disable OTP reload: yes
Temperature:24.1C Humidity:50.6%
Temperature:24.0C Humidity:50.6%
Temperature:24.0C Humidity:50.6%
Temperature:24.0C Humidity:50.6%
Temperature:25.8C Humidity:51.1%
Temperature:27.5C Humidity:55.8%
Temperature:28.2C Humidity:60.2%

 

Links

Sensirion_Humidity_Sensors_SHT20_Datasheet.pdf

 

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Code

Use a ESP32 to display DHT11 readings on a web page

by shedboy71

 

In a previous example we displayed DHT11 readings via the serial monitor and we also have had an ESP32 Web server example in the past, you can quite easily combine these two examples together to display readings from a DHT11 sensor on a web page.

Also this demonstrates how its quite easy to take readings from a sensor and display them via a web page

The schematics are the same as before and are here for reference

Parts Required

Here are the parts I used

 

Name Link
ESP32
DHT11
Connecting cables

Schematic

 

lolin32 and dht11

lolin32 and dht11

Code

You need to add the DHT11 library from adafruit to the Arduino IDE – https://github.com/adafruit/DHT-sensor-library

You will need to put your username and password for your wireless network by updating these lines

const char* ssid = “username”;
const char* password = “password”;

#include <WiFi.h>
#include "DHT.h"

// Uncomment one of the lines below for whatever DHT sensor type you're using!
#define DHTTYPE DHT11 // DHT 11

// Replace with your network credentials
const char* ssid = "username";
const char* password = "password";

WiFiServer server(80);

// DHT Sensor
const int DHTPin = A13;
// Initialize DHT sensor.
DHT dht(DHTPin, DHTTYPE);

// Temporary variables
static char celsiusTemp[7];
static char fahrenheitTemp[7];
static char humidityTemp[7];

// Client variables
char linebuf[80];
int charcount=0;

void setup() {
// initialize the DHT sensor
dht.begin();

//Initialize serial and wait for port to open:
Serial.begin(115200);
while(!Serial) {
; // wait for serial port to connect. Needed for native USB port only
}

// We start by connecting to a WiFi network
Serial.println();
Serial.println();
Serial.print("Connecting to ");
Serial.println(ssid);

WiFi.begin(ssid, password);

// attempt to connect to Wifi network:
while(WiFi.status() != WL_CONNECTED) {
// Connect to WPA/WPA2 network. Change this line if using open or WEP network:
delay(500);
Serial.print(".");
}
Serial.println("");
Serial.println("WiFi connected");
Serial.println("IP address: ");
Serial.println(WiFi.localIP());

server.begin();
}

void loop()
{
// listen for incoming clients
WiFiClient client = server.available();
if (client)
{
Serial.println("New client");
memset(linebuf,0,sizeof(linebuf));
charcount=0;
// an http request ends with a blank line
boolean currentLineIsBlank = true;
while (client.connected())
{
if (client.available())
{
char c = client.read();
Serial.write(c);
//read char by char HTTP request
linebuf[charcount]=c;
if (charcount<sizeof(linebuf)-1) charcount++;
// if you've gotten to the end of the line (received a newline
// character) and the line is blank, the http request has ended,
// so you can send a reply
if (c == '\n' && currentLineIsBlank)
{
// Sensor readings may also be up to 2 seconds 'old' (its a very slow sensor)
float h = dht.readHumidity();
// Read temperature as Celsius (the default)
float t = dht.readTemperature();
// Read temperature as Fahrenheit (isFahrenheit = true)
float f = dht.readTemperature(true);
// Check if any reads failed and exit early (to try again).
if (isnan(h) || isnan(t) || isnan(f))
{
Serial.println("Failed to read from DHT sensor!");
}
else{
// Computes temperature values in Celsius + Fahrenheit and Humidity
float hic = dht.computeHeatIndex(t, h, false);
dtostrf(hic, 6, 2, celsiusTemp);
float hif = dht.computeHeatIndex(f, h);
dtostrf(hif, 6, 2, fahrenheitTemp);
dtostrf(h, 6, 2, humidityTemp);
}

// send a standard http response header
client.println("HTTP/1.1 200 OK");
client.println("Content-Type: text/html");
client.println("Connection: close"); // the connection will be closed after completion of the response
client.println();
client.println("<!DOCTYPE HTML><html><head><meta name=\"viewport\" content=\"width=device-width, initial-scale=1\">");
client.println("<meta http-equiv=\"refresh\" content=\"2\"></head>");
client.println("<body><h1><p>ESP32 DHT11 example</h1><p>");

client.println(celsiusTemp);
client.println("*C</p><p>");
client.println(fahrenheitTemp);
client.println("*F</p><p>");
client.println(humidityTemp);
client.println("%</p>");
client.println("</body></html>");
break;
}
if (c == '\n')
{
// you're starting a new line
currentLineIsBlank = true;
memset(linebuf,0,sizeof(linebuf));
charcount=0;
}
else if (c != '\r')
{
// you've gotten a character on the current line
currentLineIsBlank = false;
}
}
}
// give the web browser time to receive the data
delay(1);
// close the connection:
client.stop();
Serial.println("client disconnected");
}
}

 

Output

Open the serial monitor and you should get the assigned IP address, once you get this paste this into your browser and all going well you should see something like this, the code is designed to refresh the page every 2 seconds

Link

DHT11 Temperature and Relative Humidity Sensor Module With Cable for Arduino

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Code

ESP32 and DHT11 sensor example

by shedboy71

DHT11 digital temperature and humidity sensor is a composite Sensor contains a calibrated digital signal output of the temperature and humidity.

Application of a dedicated digital modules collection technology and the temperature and humidity sensing technology, to ensure that the product has high reliability and excellent long-term stability.

The sensor includes a resistive sense of wet components and an NTC temperature measurement devices, and connected with a high-performance 8-bit microcontroller

dht11 module

dht11 module

Low cost, long-term stability, relative humidity and temperature measurement, excellent quality, fast response, strong anti-interference ability, long distance signal transmission, digital signal output, and precise calibration.

Parts Required

Here are the parts I used

 

Name Link
ESP32
DHT11
Connecting cables

Schematic

By using a module this avoids the need to build this on a breadboard

lolin32 and dht11

lolin32 and dht11

Code

You need to add the DHT11 library from adafruit to the Arduino IDE – https://github.com/adafruit/DHT-sensor-library

#include "DHT.h"
//here we use 14 of ESP32 to read data
#define DHTPIN A13
//our sensor is DHT11 type
#define DHTTYPE DHT11
//create an instance of DHT sensor
DHT dht(DHTPIN, DHTTYPE);

void setup()
{
Serial.begin(115200);
Serial.println("DHT11 sensor!");
//call begin to start sensor
dht.begin();
}

void loop() {
//use the functions which are supplied by library.
float h = dht.readHumidity();
// Read temperature as Celsius (the default)
float t = dht.readTemperature();
// Check if any reads failed and exit early (to try again).
if (isnan(h) || isnan(t)) {
Serial.println("Failed to read from DHT sensor!");
return;
}
// print the result to Terminal
Serial.print("Humidity: ");
Serial.print(h);
Serial.print(" %\t");
Serial.print("Temperature: ");
Serial.print(t);
Serial.println(" *C ");
//we delay a little bit for next read
delay(2000);
}

 

Output

Open the serial monitor and you should see something like this

Humidity: 23.00 % Temperature: 24.00 *C
Humidity: 23.00 % Temperature: 24.00 *C
Humidity: 24.00 % Temperature: 24.00 *C
Humidity: 24.00 % Temperature: 25.00 *C
Humidity: 24.00 % Temperature: 25.00 *C
Humidity: 25.00 % Temperature: 25.00 *C
Humidity: 29.00 % Temperature: 26.00 *C
Humidity: 29.00 % Temperature: 26.00 *C
Humidity: 29.00 % Temperature: 26.00 *C
Humidity: 28.00 % Temperature: 27.00 *C
Humidity: 29.00 % Temperature: 27.00 *C

 

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