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Simple, Reliable Temperature and Humidity Sensing for Modern Builds
The Adafruit AHT20 Temperature & Humidity Sensor Breakout Board - STEMMA QT / Qwiic is a compact digital sensor made for projects that need easy, dependable environmental readings without the quirks of older one-wire sensors. If you want a cleaner alternative to traditional hobby humidity sensors, the AHT20 is a great fit for monitoring air temperature and relative humidity in indoor projects, enclosures, and data loggers.
Because it uses a standard I2C interface, it is easy to connect to Arduino-compatible boards, Raspberry Pi, Feather boards, and other microcontrollers. Adafruit has already added the support circuitry and STEMMA QT / Qwiic connectors, so setup is fast whether you prefer header pins or solderless QT cabling.
Important: This sensor uses a single fixed I2C address, so it is not the best choice
if you need multiple AHT20 sensors on the same I2C bus. For quick plug-and-play wiring, use a
STEMMA QT cable, sold separately.
Why you'll love it
- Easy digital interface: Uses standard I2C for simple wiring and fast integration
- Modern temp + humidity sensing: A cleaner choice for many projects than older hobby sensor modules
- 3.3V and 5V friendly: Works with a wide range of maker boards
- STEMMA QT / Qwiic ready: Great for fast no-solder prototyping
- Compact breakout design: Small enough for portable, embedded, and enclosure builds
- Good general-purpose accuracy: Well suited for room monitoring, logging, and automation projects
What you can build
This breakout is ideal for indoor climate monitors, greenhouse logging, smart home dashboards, weather-adjacent projects, room comfort monitors, enclosure monitoring, classroom demos, and portable sensor nodes that need straightforward temperature and humidity readings.
Starter bundles
Pair it with an Arduino-compatible board, Adafruit Feather, or Raspberry Pi, plus a STEMMA QT cable or jumper wires for quick setup.
Recommended add-ons
Useful add-ons include OLED displays, microSD logging boards, battery packs, enclosures, and other I2C sensors for building more complete environmental monitoring systems.
Technical specifications
| Product | Adafruit AHT20 Temperature & Humidity Sensor Breakout Board - STEMMA QT / Qwiic |
|---|---|
| Main Sensor | AHT20 |
| Measured Values | Temperature and relative humidity |
| Interface | I2C |
| I2C Address | 0x38 |
| Logic / Power | 3.3V or 5V compatible |
| Temperature Range | -40°C to 85°C |
| Temperature Accuracy | ±1°C typical over the full operating range |
| Humidity Range | 0 to 100% RH |
| Humidity Accuracy | ±3% RH typical over the full operating range |
| Connector Type | STEMMA QT / Qwiic-compatible JST SH connectors |
| Revision Note | Current Adafruit listing notes the newer sensor version with PTFE filter |
Pinout & usage notes
Since this is an I2C sensor, wiring is simple and works well with modern microcontrollers and Linux-capable boards. It is a good fit for projects where you want steady environmental readings without dealing with timing-sensitive one-wire communication.
Adafruit also notes a tighter “comfort range” performance window of about ±0.3°C and ±2% RH in mid-range conditions, which makes it especially practical for room monitoring and general indoor sensing.
What’s in the box
1 × Adafruit AHT20 temperature and humidity sensor breakout board
Note: STEMMA QT cable is not included.
Frequently Asked Questions
What does this sensor measure?
It measures air temperature and relative humidity.
Can I use it with Arduino or Raspberry Pi?
Yes. It uses standard I2C and is intended for Arduino, Linux, and Raspberry Pi style projects.
Can I connect more than one on the same I2C bus?
Not directly in most cases, because it uses a single fixed I2C address.
Is the QT cable included?
No. The breakout has STEMMA QT / Qwiic connectors, but the cable is sold separately.
Can I read it often?
Yes. Adafruit notes that you can take readings as often as you like.
Manila stock. Order before 16:00 PHT, ships today via J&T or LBC. Provincial: 1–3 working days.
Schools / class POs: we accept Purchase Orders for accredited schools and universities. contact us with your PO details.
Returns: 7-day inspection window for DOA units. Email proof of issue and we ship a replacement.
Compatibility & downloads
// downloads
- GitHub PCB repo git
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