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AM2320 temperature and humidity sensor and ESP32 example

by shedboy71

AM2320 is a simple to use, high performance temperature and humidity sensor capable of long distance signal transmission up to 20 meters.The product also has high reliability and excellent stability.

It can be used in applications like HVAC, dehumidifiers, testing and detection equipment, consumer goods, automotive, automation, data loggers, weather stations, home appliances, humidity regulator, medical, and other related humidity detection control.

The sensor consists of capacitive humidity sensor and an integrated high – precision temperature sensor and connected to a high performance microprocessor. The output is already temperature compensated resulting to accurate temperature and humidity information.

 

 

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 Required

Here are the parts I used

you can connect to the sensor using a standard header the classic dupont style jumper wire.

Name Link
ESP32
AM2320
Connecting cables

Layout

Once again this layout is based around my trusty ESP32 Wemos LOLIN32 board

esp32 and am2302

esp32 and am2302

 

Code

You will need to install the folllowing library from https://github.com/EngDial/AM2320

#include <Wire.h>
#include <AM2320.h>

AM2320 th;

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

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

 

Output

Open the serial monitor

Chip = AM2320
Humidity = 47.10%
Temperature = 24.80*C

Chip = AM2320
Humidity = 48.70%
Temperature = 25.10*C

Chip = AM2320
Humidity = 53.60%
Temperature = 25.40*C

Chip = AM2320
Humidity = 55.80%
Temperature = 25.80*C

Chip = AM2320
Humidity = 59.80%
Temperature = 26.20*C

 

Links

https://akizukidenshi.com/download/ds/aosong/AM2320.pdf

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Code

ESP32 and SHT21 humidity and temperature sensor example

by shedboy71

SHT21, the new humidity and temperature sensor of Sensirion is about to set new standards in terms of size 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 signals in digital, I2C format.

With a completely new designed CMOSens® chip, a reworked capacitive type humidity sensor and an improved band gap temperature sensor the performance has been lifted even beyond the outstanding level of the previous sensor generation (SHT1x and SHT7x). For example, measures have been taken to stabilize the behavior at high humidity levels. 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 SHT21 can be changed by command (8/12bit up to 12/14bit for RH/T), low battery can be detected and a checksum helps to improve communication reliability.

SHT21 features a generation 4C CMOSens® chip. Besides the capacitive relative humidity sensor and the band gap temperature sensor, the chip contains an amplifier, A/D converter, OTP memory and a digital processing unit.

This is the breakout for the sensor that I bought.

Here is a simple schematic, again be careful as Vcc is 3.3v with this device

Schematic

Lets look at the required libraries and a basic code example, there is not much to this to be honest most of the work is done in the library

Code

You need the following library for this example – https://github.com/SodaqMoja/Sodaq_SHT2x

 

[cpp]

#include <Wire.h>
#include <Sodaq_SHT2x.h>

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

void loop()
{
Serial.print(“Humidity(%RH): “);
Serial.println(SHT2x.GetHumidity());
Serial.print(” Temperature(C): “);
Serial.println(SHT2x.GetTemperature());
Serial.print(” Dewpoint(C): “);
Serial.println(SHT2x.GetDewPoint());

delay(1000);
}

[/cpp]

Output

Open the serial monitor

Humidity(%RH): 43.24
Temperature(C): 24.56
Dewpoint(C): 11.21
*******************************************
Humidity(%RH): 43.26
Temperature(C): 24.54
Dewpoint(C): 11.21
*******************************************
Humidity(%RH): 43.52
Temperature(C): 24.93
Dewpoint(C): 11.62
*******************************************
Humidity(%RH): 44.13
Temperature(C): 25.10
Dewpoint(C): 12.11
*******************************************
Humidity(%RH): 44.77
Temperature(C): 25.59
Dewpoint(C): 12.80
*******************************************

Links

SHT21 Digital Humidity And Temperature Sensor Module

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Code

ESP32 and AM2302 sensor example

by shedboy71

AM2302 capacitive humidity sensing digital temperature and humidity module is one that contains the compound has been calibrated digital signal output of the temperature and humidity sensors.

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 capacitive sensor wet components and a high-precision temperature measurement devices, and connected with a high-performance 8-bit microcontroller. The product has excellent quality, fast response, strong anti-jamming capability, and high cost

Ultra-low power, the transmission distance, fully automated calibration, the use of capacitive humidity sensor, completely interchangeable, standard digital single-bus output, excellent long-term stability, high accuracy temperature measurement devices.

Parts Required

Here are the parts I used

The sensor you can pick up in the $6 price range – you can connect to the sensor using a standard header the classic dupont style jumper wire.

Name Link
ESP32
AM2302
Connecting cables

Schematic

lolin32 and dht22

lolin32 and dht22

 

Code

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

#include "DHT.h"

#define DHTPIN A13
//our sensor is DHT22 type
#define DHTTYPE DHT22
//create an instance of DHT sensor
DHT dht(DHTPIN, DHTTYPE);
void setup() {
Serial.begin(115200);
Serial.println("DHT22 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: 53.30 % Temperature: 28.90 *C
Humidity: 53.30 % Temperature: 28.90 *C
Humidity: 57.10 % Temperature: 28.90 *C
Humidity: 57.30 % Temperature: 29.00 *C
Humidity: 57.10 % Temperature: 29.10 *C
Humidity: 57.30 % Temperature: 29.20 *C
Humidity: 58.40 % Temperature: 29.30 *C

 

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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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