The SHT31 is a high-accuracy digital humidity and temperature sensor designed and manufactured by Sensirion. It offers excellent performance and a wide range of features, making it ideal for advanced consumer products, industrial systems, and Internet of Things (IoT) applications. Its precision and reliability are well-suited for environmental monitoring, weather stations, smart home automation, and HVAC systems.
This circuit features an Arduino Nano microcontroller interfaced with an Ethernet W5500 module for network connectivity and an SHT31 sensor for temperature and humidity measurements. The Arduino Nano communicates with the Ethernet module via SPI and reads data from the SHT31 sensor using I2C, enabling remote monitoring of environmental conditions.
Open Project in Cirkit Designer
This circuit integrates an ESP32 microcontroller with a DHT22 temperature and humidity sensor, an Adafruit SHTC3 sensor, and a 2-channel relay module. The ESP32 reads environmental data from the sensors and can control external devices through the relay module.
Open Project in Cirkit Designer
This circuit features a Nano 3.0 ATmega328P microcontroller connected to an LED dot display, a real-time clock (RTC DS3231), and a humidity and temperature sensor (SHT21). The microcontroller communicates with the RTC and SHT21 via I2C (using A4 and A5 as SDA and SCL lines, respectively), and it controls the LED display through SPI-like signals (using D10, D11, and D12 for DIN, CS, and CLK). The circuit is designed to display time and environmental data on the LED display, with all components sharing a common power supply and ground.
Open Project in Cirkit Designer
This circuit features an ESP32 microcontroller interfaced with two sensors: a DHT11 for temperature and humidity data, and an AHT10 for more precise temperature and humidity measurements. The ESP32 collects data from these sensors via GPIO pins and I2C communication, respectively, and powers both sensors through its 3.3V and GND pins.
Open Project in Cirkit Designer| Pin Number | Name | Description |
|---|---|---|
| 1 | VDD | Supply voltage |
| 2 | GND | Ground |
| 3 | SDA | Serial Data Line for I2C |
| 4 | SCL | Serial Clock Line for I2C |
| 5 | nRESET | Active low reset pin |
| 6 | ALERT | Alert pin (optional use) |
| 7 | ADDR | I2C address selection pin |
To use the SHT31 sensor in a circuit:
#include <Wire.h>
#include "SHT31.h"
SHT31 sht31 = SHT31();
void setup() {
Serial.begin(9600);
Wire.begin();
if (!sht31.begin(0x44)) { // Set to 0x45 if ADDR pin is tied to VDD
Serial.println("Could not find a valid SHT31 sensor, check wiring!");
while (1) delay(1);
}
}
void loop() {
float temp = sht31.getTemperature();
float hum = sht31.getHumidity();
if (!isnan(temp)) { // Check if 'temp' is not an error value
Serial.print("Temp *C = "); Serial.println(temp);
} else {
Serial.println("Failed to read temperature");
}
if (!isnan(hum)) { // Check if 'hum' is not an error value
Serial.print("Hum. % = "); Serial.println(hum);
} else {
Serial.println("Failed to read humidity");
}
delay(1000);
}
Q: Can the SHT31 sensor be used outdoors? A: Yes, but it should be protected from direct exposure to water and sunlight.
Q: How can I extend the I2C cable length? A: Use shielded cables and lower the pull-up resistor value to maintain signal integrity.
Q: What is the purpose of the ALERT pin? A: The ALERT pin can be used to trigger an interrupt on the host microcontroller when humidity or temperature exceeds programmed limits.
Q: How do I calibrate the sensor? A: The SHT31 is factory-calibrated. However, for critical applications, you may perform additional calibration using known humidity and temperature references.
Q: Is there a sleep mode to reduce power consumption? A: Yes, the SHT31 supports a low-power mode that can be activated via I2C commands.
This documentation provides a comprehensive guide to integrating and using the SHT31 sensor in various applications. For further information, consult the manufacturer's datasheet and application notes.