From SparkFun to Reality: Building a Custom HUD with a Qwiic Transparent OLED (US, CA, AU Maker Guide)

Heads-Up Displays (HUDs) have a certain magic to them. They feel futuristic, pulling critical data from our devices and floating it in our line of sight. For years, this tech was the exclusive domain of fighter jets and luxury cars. Not anymore. Thanks to the maker movement and incredible ecosystems like SparkFun's Qwiic Connect System, building your own custom data display is easier and more accessible than you might think.

This project-based tutorial will guide you through building a functional, non-distracting Heads-Up Display using a SparkFun Transparent OLED and a GPS module. We'll show you how the solderless Qwiic system makes assembly a snap and provide the code to create a real-time speedometer. This is a perfect project for makers in the US, Canada, and Australia looking to step up from beginner tutorials to a build that's both practical and incredibly cool.

Part 1: The Concept & The Qwiic Components

The Concept: A Simple, Modular HUD

Our goal is to create a simple HUD that can be used in a car, on a bike, or for any project where you want to see data without looking down. The core of the system will be a transparent OLED screen facing upwards, with its image reflected off a clear surface angled at 45 degrees towards the user's eyes. We will start by displaying speed from a GPS module, but thanks to the Qwiic system, expanding it later will be incredibly easy.

The Shopping List: Your Qwiic Toolkit

The beauty of the Qwiic ecosystem is its plug-and-play nature. All these components connect with simple, polarized cables, making errors almost impossible and eliminating the need for soldering.

1. The Display: The star of the show is the SparkFun Transparent Graphical OLED Breakout (Qwiic). This 1.5-inch display is brilliantly lit and has a 128x56 transparent pixel area.
2. The Microcontroller: These displays require a bit more RAM than a basic Arduino Uno. A great choice is a board with an ESP32 chip, like the SparkFun Thing Plus - ESP32 WROOM, which has plenty of power and built-in WiFi/Bluetooth for future projects.
3. The Sensor: To get our speed data, we'll use a SparkFun GPS Breakout (Qwiic). These modules are highly sensitive and can provide speed, altitude, and location data.
4. The Cables: A handful of Qwiic Cables of various lengths (e.g., 50mm, 100mm). It's always good to have a few options.
5. The Power Source: A simple USB Micro-B Cable and a USB power bank or wall adapter.

Part 2: Assembling the 'Brain' - The Magic of Qwiic

This is where you'll fall in love with the Qwiic system. Traditionally, you'd be cutting, stripping, and soldering at least 12 different connections. With Qwiic, it takes about 15 seconds.

1. Take your ESP32 Thing Plus board.
2. Plug one end of a Qwiic cable into one of the Qwiic ports on the board.
3. Plug the other end into one of the Qwiic ports on the Transparent OLED Breakout.
4. Take a second Qwiic cable. Plug it into the other Qwiic port on the OLED Breakout.
5. Plug the other end of that cable into your Qwiic GPS Module.

That's it. You have just created a "daisy chain," connecting all three devices on the same I2C bus. Power and data will flow through these simple cables.

"Hello World" Sanity Check

Before we build the physical rig, let's make sure the display is working.

1. Connect your ESP32 to your computer via USB.
2. Set up your Arduino IDE for the ESP32 by following SparkFun's excellent hookup guide.
3. Install the required libraries from the Arduino Library Manager: "SparkFun HyperDisplay" and "SparkFun Transparent Graphic OLED UBER Library".
4. Load the Example1_Basics sketch from the SparkFun Transparent Graphic OLED library.
5. Upload the code. You should see text and graphics appear on your OLED screen. If it works, you're ready to move on!

Part 3: Building the HUD Rig - The Physical Setup

Now we need to build a simple housing to create the HUD effect. The principle is simple: the OLED screen lies flat, facing up, and a clear "combiner" screen sits at a 45-degree angle above it to reflect the image to your eyes.

• Simple Mockup (Recommended First): Start with cardboard! Cut a simple box shape that can hold your OLED flat at the bottom. Cut a slot at a 45-degree angle to hold a small piece of clear acrylic or even a spare CD jewel case. This lets you test the angles and visibility easily.
• 3D Printing: Once you're happy with the geometry, you can design a more permanent enclosure. There are many existing HUD designs on sites like Thingiverse that you can adapt for the dimensions of the SparkFun OLED.
• Laser-Cut Acrylic: For a very clean, professional look, you can design a housing with interlocking acrylic parts and have it laser cut.

The Key: The OLED display should be mounted securely at the base. The reflector (combiner) needs to be a clear, thin piece of plastic or glass angled perfectly at 45 degrees.

Part 4: The HUD Code - Bringing it to Life

Here is a complete Arduino sketch that will read data from the Qwiic GPS module and display the speed in Kilometers Per Hour (KPH) on your transparent OLED.

Required Libraries (Install via Arduino Library Manager):

• SparkFun HyperDisplay
• SparkFun Transparent Graphic OLED UBER Library
• SparkFun u-blox GNSS Arduino Library

#include <Wire.h>
#include "SparkFun_HyperDisplay.h"
#include "hyperdisplay_uber_tgoled.h"
#include <SparkFun_u-blox_GNSS_Arduino_Library.h>

SFE_UBLOX_GNSS myGNSS;
HyperDisplay_UBER_TGOLED myTOLED;

void setup() {
  Wire.begin(); // Start I2C

  // Check if the TOLED is connected
  if (myTOLED.begin() == false) {
    Serial.println("TOLED not detected. Freezing.");
    while (1);
  }

  // Check if the GPS is connected
  if (myGNSS.begin() == false) {
    myTOLED.clear();
    myTOLED.setCursor(0, 20);
    myTOLED.print("GPS not detected");
    myTOLED.display();
    while (1);
  }

  myTOLED.clear();
  myTOLED.display();
}

void loop() {
  // Read GPS data
  long speed = myGNSS.getGroundSpeed(); // Speed in mm/s
  float speedKPH = speed * 0.0036;     // Convert mm/s to km/h

  // Clear the display buffer
  myTOLED.clear();

  // Set up the text properties
  myTOLED.setTextSize(2);
  myTOLED.setCursor(10, 20); // Position the text

  // Display the speed
  myTOLED.print(speedKPH, 1); // Print with 1 decimal place
  myTOLED.print(" KPH");

  // Push the buffer to the screen
  myTOLED.display();

  delay(250); // Update speed 4 times per second
}

How the Code Works:

1. It includes all the necessary libraries for the display and the GPS module.
2. In setup(), it initializes the I2C communication and checks to make sure both the OLED and the GPS module are connected properly.
3. In loop(), it continuously gets the latest ground speed from the GPS module.
4. It converts the speed from millimeters per second (the library's default) to kilometers per hour.
5. It clears the previous image, sets the text size and position, and prints the new speed to the screen.
6. The myTOLED.display() command is what actually sends the image buffer to be displayed.

Part 5: Ideas for Expansion

The best part of the Qwiic ecosystem is how easy it is to add more functionality. Now that you have a working HUD, what's next?

• Add a Compass: Plug in a Qwiic 3-Axis Compass and display a heading along with your speed.
• Create a G-Force Meter: Use a Qwiic Accelerometer to measure and display acceleration forces during cornering or braking.
• Build a Parking Aid: Add a Qwiic Distance Sensor facing backward to create a simple reverse parking assistant.
• Monitor Your Environment: Use a Qwiic Environmental Combo Breakout to display temperature, humidity, and barometric pressure.

Conclusion

Congratulations! You've just built a custom Heads-Up Display—a project that truly sits at the intersection of practical electronics and futuristic design. The SparkFun Qwiic system removes the most common barriers for intermediate makers, allowing you to focus on the creative aspects of your build rather than the frustrations of soldering and wiring. This project is a fantastic foundation, and we can't wait to see how you expand upon it. Share your builds with the vibrant maker communities in the US, Canada, Australia, and beyond!

FAQ Section

1. How do I make the reflection clear and not a "ghost" image?

"Ghosting" or a double image is a common issue with DIY HUDs. It happens because the image reflects off both the front and back surfaces of your clear reflector. To minimize this, you can:

• Use thinner material: A thinner piece of acrylic will have less distance between its front and back surfaces, making the ghost image less noticeable.
• Use specialized HUD film: You can buy special transparent film designed for car HUDs that can be applied to your reflector. This film is engineered to be reflective to the specific wavelength of your OLED's light while remaining transparent to other light, which dramatically improves clarity.

2. Is the display bright enough to be seen in daylight?

It depends on the conditions. In direct, bright sunlight, the OLED's reflection will be difficult to see. However, for use at dawn, dusk, at night, or on overcast days, it is perfectly visible. For the best daylight visibility, you can create a "shroud" around your display and reflector to shield it from ambient light, which will make the reflection appear much brighter.

3. Can I use a Raspberry Pi with Qwiic components for this project?

Absolutely! SparkFun makes it very easy. You can use a Qwiic pHAT for Raspberry Pi or a Qwiic SHIM, which are small boards that plug directly onto the Pi's GPIO header and provide Qwiic connectors. You would then need to find the equivalent Python libraries for the GPS and OLED display, which are readily available. This is a great upgrade if you want to add more complex processing, data logging, or a graphical user interface to your HUD project.