SparkFun Qwiic HAT for Raspberry Pi – Complete Hookup Guide

Introduction

The SparkFun Qwiic HAT gives you a fast, plug‑and‑play way to connect the I²C bus on any Raspberry Pi to the expansive Qwiic ecosystem. It bridges the Pi’s GND, 3.3 V, SDA, and SCL pins to four Qwiic connector ports while also breaking out key GPIO pins for convenient access. Because Qwiic supports daisy‑chaining (provided each device has a unique address), you can stack an unlimited number of sensors to build a powerful sensing tower.

Required Materials

• Any Raspberry Pi with 2×20 male GPIO headers (e.g., Pi 3 or Pi 4). If you’re using a Pi Zero W, solder the male headers yourself.
• Qwiic HAT (SparkFun product).
• Qwiic-enabled sensors or breakout boards. Examples:
  • Environmental Combo Breakout – CCS811/BME280 (Qwiic)
  • Spectral Sensor Breakout – AS7262 Visible (Qwiic)
  • GPS Breakout – XA1110 (Qwiic)
  • Qwiic Adapter (for non‑Qwiic devices)
• Qwiic cables (various lengths for flexible layouts): 50 mm, 100 mm, 200 mm, 500 mm.

Required Setup Tools

• USB mouse
• USB keyboard
• HDMI monitor, TV, or VGA adapter
• 5 V power supply (minimum 2 A for Pi 3/4, 2.5 A for Pi Zero W)

Suggested Reading

• Qwiic System Overview – learn the basics of the Qwiic interface.
• I²C Basics – an introduction to the I²C protocol, essential for any Raspberry Pi project.

Hardware Overview

The Qwiic HAT features four Qwiic connector ports, all wired to the same I²C bus. In addition, it exposes several key GPIO pins on the Raspberry Pi’s 40‑pin header, making it straightforward to integrate additional peripherals without soldering.

Hardware Assembly

1. Align the Qwiic HAT with the Pi’s 2×20 male header. Ensure the arrow labeled “USB” on the HAT points toward the Pi’s USB port.
2. Gently press the HAT into place; the pins should snap securely into the header.
3. Attach your Qwiic sensors or breakout boards using the appropriate Qwiic cable lengths.
4. Verify that all connections are solid before powering on the Pi.

I²C on Raspberry Pi

Operating System & Library Install

Start with a fresh Raspbian (now Raspberry Pi OS) image if you’re setting up a new SD card. For convenience, download the NOOBS image (v2.4.4 at the time of writing) and follow the official installation guide.

1. Download the NOOBS image.
2. Flash it to your SD card and boot the Pi.
3. Use sudo apt update && sudo apt upgrade to bring packages up to date.
4. Install WiringPi via sudo apt install wiringpi (or use the WiringPi installation instructions if you prefer the latest source).

After installation, test WiringPi with:

gpio -v
gpio readall

You should see the WiringPi version and a pinout table for the Pi’s 40‑pin header.

Enable I²C

Unlike SPI, the I²C interface is disabled by default. Enable it with sudo raspi-config:

1. Launch sudo raspi-config.
2. Navigate to 5 Interfacing Options.
3. Select P5 I²C and answer yes to enable.
4. Choose OK and Finish to reboot.

After reboot, confirm the interface is active with ls /dev/*i2c*, which should list /dev/i2c-1—the user‑mode I²C bus.

Test Your Qwiic HAT

With the HAT and a sensor attached, run i2cdetect -y 1 to scan the bus. You should see the sensor’s address appear on the grid, indicating a successful connection.