GY-SHT40 Digital Temperature and Humidity Sensor Module - Ultra Low Power I2C

Specifications

• Sensor Chip: SHT40 (4th Generation)
• Interface: I2C (Standard Mode & Fast Mode compatible)
• I2C Address: 0x44 (Fixed)
• Temperature Range: -40°C to 125°C
• Temperature Accuracy: ±0.2°C (Typical)
• Humidity Range: 0% to 100% RH
• Humidity Accuracy: ±1.8% RH (Typical)
• Standby Current: Ultra-low (< 400 nA)

Applications

• Battery-Powered ESP32/ESP8266 Weather Nodes
• Smart Home Thermostats & HVAC Monitoring
• Greenhouse and Hydroponics Climate Logging
• Portable Environmental Monitors

Unlock New Capabilities

• Past Projects: If you've previously built projects using the DHT11, DHT22, or even the SHT20...
• Feature Upgrade: The GY-SHT40 unlocks an entirely new tier of ultra-low power consumption for coin-cell or solar applications, along with an integrated heater to survive high-humidity, condensing environments without sensor failure.
• Effort Level: Intermediate. Requires basic breadboarding and standard I2C library installation.

Package Includes:

• 1 x GY-SHT40 Digital Temperature and Humidity Sensor Module - Ultra Low Power I2C

Frequently Asked Questions (FAQ)

• What is the default I2C address of the GY-SHT40?
  The fixed I2C address is 0x44.
• Can I change the I2C address to use multiple sensors?
  No, the address is hardwired. You must use an I2C multiplexer (like the TCA9548A) to use multiple GY-SHT40 modules on one microcontroller.
• What is the difference between the SHT40 and SHT41?
  They share the same architecture, but the SHT41 has slightly tighter accuracy tolerances for extreme precision needs. The SHT40 is standard high-precision.
• Is this module safe to use with a 5V Arduino Uno?
  Yes, the GY breakout board contains the necessary components to work safely with 5V logic and power.
• Does the GY-SHT40 require calibration?
  No, the SHT40 chip is factory-calibrated and ready to output accurate data immediately.
• Why does my sensor read exactly 125°C and 100% humidity?
  This is a default error state usually caused by a wiring mistake, missing connection on SDA/SCL, or the wrong I2C address in your code.
• What is the built-in heater used for?
  The heater can be activated via software to evaporate condensation on the sensor element, preventing false readings in heavily saturated environments.
• Will using the heater affect my temperature readings?
  Yes, while the heater is active, the local temperature will rise and relative humidity will drop. It should only be pulsed briefly when condensation is suspected.
• How much power does the SHT40 use?
  It is exceptionally efficient, using less than 400nA in standby mode, making it ideal for battery-operated IoT nodes.