Looking for Gy-21 Module? GY-21 HTU21 Sensor Module is available at Zbotic with fast shipping across India.
Product Description
The HTU21D is a digital sensor that measures humidity and temperature with high accuracy, low cost and easy use. It is suitable for environmental sensing and data logging, such as in weather stations or humidor control systems. It requires only two lines for I2C communication, which also provide very accurate temperature readings as a bonus!
The sensor has four pins to connect to a project: VCC, GND, and two data lines for I2C communication. The breakout board has 4.7k pull-up resistors for I2C communication, which can be turned off if multiple I2C devices are connected on the same bus.
Features:
- 2.1V to 3.6V Supply Voltage
- Low power consumption – 0.15uA typical
- I2C interface
- Resolution: 0.04%RH, 0.02°C
- Accuracy: ±2%RH, ±3°C
Package Includes:
1 x GY-21 HTU21 Sensor Module
1 x 4 Pin Male Header
Tutorial:
https://lastminuteengineers.com/htu21d-temperature-humidity-sensor-arduino-tutorial/
GY-21 HTU21 Sensor Module Overview
The GY-21 HTU21 Sensor Module is a compact digital breakout that accurately measures relative humidity and temperature via an I2C interface. Designed for low-power operation and simple integration, it’s ideal for environmental monitoring and data-logging projects.
Key Features of GY-21 HTU21 Sensor Module
- 2.1 V to 3.6 V supply voltage range for 3.3 V microcontroller compatibility
- Ultra-low current draw: 0.15 µA typical in standby
- I2C communication with onboard 4.7 kΩ pull-up resistors (user-disableable)
- High resolution: 0.04 % RH for humidity, 0.02 °C for temperature
- Accuracy of ±2 % RH and ±3 °C across operating conditions
- Genuine module, fast shipping across India from Zbotic
Applications and Use Cases
- Home and industrial weather stations for real-time climate tracking
- Greenhouse and hydroponic systems to maintain optimal humidity
- HVAC control units for precise environmental regulation
- Data-logging and remote sensing nodes in IoT networks
- Humidor or cold-chain monitoring to protect sensitive goods
How to Use GY-21 HTU21 Sensor Module
Wire the module’s VCC to your 3.3 V rail (2.1–3.6 V), GND to ground, SDA to I2C data, and SCL to I2C clock. Install an HTU21D-compatible library (for example, Adafruit_HTU21D) and initialize the sensor over the I2C bus. Read humidity and temperature via provided functions; disable onboard pull-ups only if adding more I2C devices to the same bus.
Why Buy from Zbotic?
- Genuine Products: All items sourced from authorized distributors
- Fast Shipping: Orders ship within 24 hours with tracking (non backordered products)
- Free Shipping: Free delivery on qualifying orders
- COD Available: Cash on Delivery, UPI, cards, net banking
- Technical Support: Expert help for setup and troubleshooting
- Easy Returns: Hassle-free replacement for defective products
Frequently Asked Questions
What is the default I2C address of the GY-21 HTU21 module?
The sensor uses a fixed I2C address of 0x40. Simply point your microcontroller’s I2C library to 0x40 to begin communication.
Do I need external pull-up resistors for I2C lines?
No. The GY-21 board includes 4.7 kΩ pull-up resistors on SDA and SCL. You can leave them enabled for a single-sensor setup, or remove the onboard resistors when multiple devices share the bus.
Which libraries support this sensor on Arduino?
You can use the Adafruit_HTU21D library or any HTU21D-compatible driver. After installing via Library Manager, include Wire.h, initialize the sensor in setup(), then call readHumidity() and readTemperature() in loop().
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Read More →Technical Specifications
| Model | GY-21 |
|---|---|
| SKU | AI2630 |
| Weight | 0.01 kg |
| Availability | In Stock |
Applications & Use Cases
The GY-21 HTU21 Sensor Module is a versatile temperature & humidity sensor used across a wide range of applications including weather stations, greenhouse monitoring, HVAC systems, cold chain logistics, and server room monitoring.
Common use cases:
- Building a home weather station with Arduino
- Monitoring greenhouse conditions via IoT
- Alerting when server room temperature exceeds threshold
This product is ideal for IoT developers, agricultural engineers, and home automation enthusiasts.
Technical Tip: DHT22 offers better accuracy than DHT11. For precision applications, use SHT31 or BME280. Ensure adequate ventilation around the sensor.
Shipping & Delivery
- Free shipping on orders above ₹999 across India
- Dispatched within 1-3 business days
- Expected delivery: 3-7 business days depending on location
- Secure packaging to ensure safe transit of electronic components
