GY-21 Si7021 Humidity & Temperature Sensor Module I2C

GY-21 Si7021 High-Accuracy Humidity & Temperature Sensor Module

The GY-21 Si7021 Sensor Module is a compact, industrial-grade humidity and temperature sensing solution built for makers, engineers, and electronics enthusiasts. Featuring the reliable Si7021 chip, this module communicates over the I2C/IIC interface, making it straightforward to integrate with Arduino, Raspberry Pi, and other microcontroller platforms. Whether you're building a weather station, monitoring environmental conditions, or developing a smart home project, this sensor delivers precise, repeatable readings in a tiny SMD package.

Key Features

• Industrial-Grade Accuracy: The Si7021 chip provides high-precision humidity and temperature measurements for demanding applications.
• I2C / IIC Interface: Simple two-wire communication for easy integration with popular development boards.
• Ultra-Lightweight: Weighs just 0.68g — ideal for portable and space-constrained projects.
• Low Input Current: Operating input current per pin: -10 to +10mA, keeping power consumption minimal.
• SMD Design: Surface-mount construction for clean, professional circuit board integration.
• Customizable Quantity: Available in 1-piece or 3-piece options to suit your project needs.

Specifications

• Model: GY-21 / Si7021
• Interface: I2C / IIC
• Measurement: Humidity & Temperature
• Input Current Per Pin: -10 to +10mA
• Weight: 0.68g
• Package: SMD
• Quantity Options: 1pcs / 3pcs

What's Included

• GY-21 Si7021 Sensor Module(s) (SMD, quantity as selected)

Perfect For

• DIY weather stations and environmental monitors
• Smart home automation systems
• Greenhouse and grow-room climate control
• Industrial data logging and monitoring
• Arduino, Raspberry Pi, and ESP8266/ESP32 projects

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Frequently Asked Questions

Q: What does the GY-21 Si7021 Sensor Module measure?

A: The GY-21 Si7021 Sensor Module measures both relative humidity and ambient temperature with high accuracy, making it suitable for a wide range of environmental monitoring and IoT applications.

Q: What interface does the GY-21 Si7021 use?

A: The GY-21 Si7021 uses the standard I2C (IIC) two-wire interface, which is compatible with Arduino, Raspberry Pi, ESP8266, ESP32, and most popular microcontroller and single-board computer platforms.

Q: How many units can I order at once?

A: You can select either a 1-piece or 3-piece option at checkout, so you can stock up for multiple projects or just grab a single module to get started.

Q: Is this sensor suitable for beginner electronics projects?

A: Yes! The GY-21 Si7021 Sensor Module is beginner-friendly thanks to its simple I2C interface and compact design. Numerous open-source libraries and tutorials are available to help you get up and running quickly.

Production & Packaging Notice

To maintain high stock availability and fast shipping times, our items are sourced from multiple verified manufacturing facilities. While the core quality, materials, and product specifications remain identical, you may notice slight variations in the packaging design, manufacturing origin, or the wording of the printed instructions.