SparkFun QwiicBus Hookup Guide

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Introduction

Introducing the SparkFun QwiicBus system! The QwiicBus is a fast and easy way to extend the range of your I2C bus. The QwiicBus system features two boards: the SparkFun QwiicBus EndPoint and the SparkFun QwiicBus MidPoint. SparkFun also offers the QwiicBus Kit that includes two EndPoints, one MidPoint and two Ethernet cables to get you started with the QwiicBus.

SparkFun QwiicBus Kit

SparkFun QwiicBus Kit

KIT-17250
$39.95
SparkFun QwiicBus - EndPoint

SparkFun QwiicBus - EndPoint

COM-16988
$10.95
SparkFun QwiicBus - MidPoint

SparkFun QwiicBus - MidPoint

COM-18000
$20.95
1

Using NXP's PCA9615 differential I2C bus buffer IC, the QwiicBus converts the two default I2C signals into four differential signals (two for SCL and two for SDA). The differential signals are sent over an Ethernet cable, which attaches to the EndPoint or MidPoint through the on-board RJ-45 connectors. Differential signaling allows the I2C signals to reach distances of over 100 feet while still maintaining their signal integrity. In our testing using two EndPoints, four MidPoints, at least one Qwiic device on each node and over 200 feet of Ethernet cable, we were able to use all devices with nearly no signal integrity loss!

The EndPoint acts as the starting and ending points of the QwiicBus and the MidPoint allows you to add a drop-in I2C connection to your long-distance differential I2C chain wherever you would like.

These boards grew out of a collaboration with FarmHand Automation. While developing autonomous micro-tractors to help small farmers grow their business, Farmhand realized they needed a low cost, open source CAN/Modbus alternative. Read more about their story here. FarmHand founder, Alex Jones said, "We knew the sensors we wanted to use, but as soon as you need to communicate over long distances in noisy environments things get complicated. The Qwiic Midpoint is going to solve a lot of that headache." The QwiicBus MidPoint and QwiicBus EndPoint are ideal for applications that require long-range communication over Ethernet, such as agricultural technology or data collection/monitoring in rural/remote areas.

Whether you have a robot with multiple I2C devices throughout it like FarmHand, a sensor network project with multiple sensors over a large area or other I2C projects you can think of that require a wired signal transmission over long distances, the QwiicBus makes that communication a breeze!

Required Materials

If you are using the QwiicBus Kit, you'll have the required boards and Ethernet cables to assemble your QwiicBus circuit. Otherwise, you'll want to pick up two EndPoints and however many MidPoints your project needs.

Along with the QwiicBus boards, you will need the following materials to follow along with this tutorial. You may not need everything though depending on what you have. Add it to your cart, read through the guide, and adjust the cart as necessary.

A microcontroller is needed to control any I2C devices attached to your QwiicBus. Below are a few options that come Qwiic-enabled out of the box:

SparkFun Qwiic Pro Micro - USB-C (ATmega32U4)

SparkFun Qwiic Pro Micro - USB-C (ATmega32U4)

DEV-15795
$19.95
4
SparkFun RedBoard Qwiic

SparkFun RedBoard Qwiic

DEV-15123
$19.95
9
SparkFun Thing Plus - ESP32 WROOM

SparkFun Thing Plus - ESP32 WROOM

WRL-15663
$20.95
7
SparkFun RedBoard Artemis

SparkFun RedBoard Artemis

DEV-15444
$19.95
8

If you would prefer to use a single-board computer (SBC) like a Raspberry Pi or Jetson Nano as your controller, the products below will also work with the QwiicBus:

NVIDIA Jetson Nano Developer Kit (V3)

NVIDIA Jetson Nano Developer Kit (V3)

DEV-16271
$99.00
11
SparkFun DLI Kit for Jetson Nano

SparkFun DLI Kit for Jetson Nano

KIT-16308
$174.95
5

SparkFun Raspberry Pi 4 Desktop Kit - 4GB

KIT-16386

Raspberry Pi 4 Model B (2 GB)

DEV-15446
4

If your favorite microcontroller or single board computer is not already Qwiic-enabled, you can add that functionality with one or more of the following items:

SparkFun Qwiic pHAT v2.0 for Raspberry Pi

SparkFun Qwiic pHAT v2.0 for Raspberry Pi

DEV-15945
$6.95
2
SparkFun Qwiic Adapter

SparkFun Qwiic Adapter

DEV-14495
$1.50
1
SparkFun Qwiic Shield for Arduino

SparkFun Qwiic Shield for Arduino

DEV-14352
$6.95
6
SparkFun Qwiic SHIM for Raspberry Pi

SparkFun Qwiic SHIM for Raspberry Pi

DEV-15794
$0.95
10

You will also probably want a few Qwiic cables to connect your devices on your I2C bus:

Qwiic Cable - 100mm

Qwiic Cable - 100mm

PRT-14427
$1.50
Qwiic Cable - 500mm

Qwiic Cable - 500mm

PRT-14429
$1.95
1
Qwiic Cable - 50mm

Qwiic Cable - 50mm

PRT-14426
$0.95

Qwiic Cable - 200mm

PRT-14428

Finally, if you are not using the QwiicBus Kit you'll need at least one straight through Ethernet cable.

Optional Extras for Alternate QwiicBus Power Configurations

The QwiicBus offers multiple power configurations intended for applications where many devices need to be powered over the QwiicBus. We cover these configurations in more detail in the Hardware Overview and Hardware Assembly. To use these configurations you will need some extra hardware and tools. Click the button below to view some recommended products for alternate power configurations.

Suggested Reading

If you aren't familiar with the Qwiic system, we recommend reading here for an overview.

Qwiic Connect System
Qwiic Connect System

We would also recommend taking a look at the following tutorials if you aren't familiar with the topics they cover.

Logic Levels

Learn the difference between 3.3V and 5V devices and logic levels.

Electric Power

An overview of electric power, the rate of energy transfer. We'll talk definition of power, watts, equations, and power ratings. 1.21 gigawatts of tutorial fun!

I2C

An introduction to I2C, one of the main embedded communications protocols in use today.

How to Work with Jumper Pads and PCB Traces

Handling PCB jumper pads and traces is an essential skill. Learn how to cut a PCB trace, add a solder jumper between pads to reroute connections, and repair a trace with the green wire method if a trace is damaged.