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A cheap and cheerful head-up display. Made from a baseball cap, some optics, and your smartphone. Read more

Melbourne, AU Hardware
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pledged of $50,000 goal
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Funding Unsuccessful

This project's funding goal was not reached on May 1, 2014.

A cheap and cheerful head-up display. Made from a baseball cap, some optics, and your smartphone.

About this project

The name Matt Hat was originally meant as a joke, but people seemed to like it, so it stuck. The hat itself is an attempt to make an augmented reality head-up display as cheaply as possible.

It's functional, not fashionable.
It's functional, not fashionable.

It consists of a baseball cap, a curved reflective half-mirrored visor, and an attachment part. After cutting a rectangular slot in the brim of the cap, you hook in the attachment part, snap on the visor, and lock them in place with a rubber band.

Next you slide a smartphone into the slot and hold it in place with another rubber band. Anything appearing on the bottom of the phone's screen will be reflected back by the visor at a perceived distance of about a metre, overlaying your field of view. Just like a Terminator's view of the world!

The view from inside.
The view from inside.


This is actually the third iteration of the hat's design. The first two versions were blogged about here and here.

The first version was built during my PhD in geospatial science. There is a lot of spatial data out there, and I thought it would be cool if you could see it as you moved around. Except that prototype didn't work very well.

The original prototype.
The original prototype.

To get to the final design a few problems had to be overcome. To fix image distortion problems the visor needed a lot of number crunching and ray-tracing simulations to come up with a suitable curved surface. And getting it CNC machined forced me to learn more about CAD formats than I ever wanted to know!

But now that the design works reliably, getting the hats mass-produced is fairly straightforward. The solid parts are designed to be injection moulded, and although the set-up costs for injection moulding are rather high, the unit costs are low. Which is why I'm using crowd-funding.


Of course, the hardware is just one part of the product. A head-up display also needs software, and the requirements are a bit different to those for desktops or smartphones.

First of all, it may be desirable to run applications remotely. For example, you might want to run an application on a smartphone in your pocket and have it displayed by the hat. To make that work you need some kind of visual display protocol, like X Windows.

So as a practice run I implemented an X Windows server for Android to get a feel for the protocol. After shedding a bunch of legacy commands, adding some new graphics features, and eliminating most of the return traffic, I came up with the Compact Augmented Reality Protocol, or CARP.

As well as enabling remote viewing, CARP provides a number of other features useful for augmented reality applications. I won't bore you with the details, but if you want to know more, the full specifications and an Android software development kit can be found at

Also available at are news and announcements, demo source code and tutorials, a developers forum, and general advice for getting the most out of your Matt Hat.

Risks and challenges

The design of the Matt Hat is finished, and the CAD files are ready to go. The manufacturing, packaging, and logistics will be outsourced to a full-service contract manufacturer who will carry out or subcontract the following tasks ...

- Construction of the injection moulds (to be commenced once the $50k threshold is reached)
- Injection moulding the two plastic components that make up the Matt Hat.
- Vacuum metallizing the visors.
- Packing the plastic components and a baseball cap into cardboard boxes.
- Shipping the boxes to everyone who paid $50.

The process is likely to take about 6 weeks.

On the software side, my day job is writing Android smartphone applications for major clients, so maintaining the software development kit and releasing a few demo apps won't be a problem. They may not look great (I'm a developer, not a designer!), but they'll work.

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  1. Select this reward

    Pledge $5 or more
    About $5 USD

    2 backers

    Thanks mate! Your name will be added to the contributors page at and the world will know of your generosity.

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  2. Select this reward

    Pledge $50 or more
    About $46 USD

    5 backers

    You will receive one Matt Hat in the mail. This consists of a baseball cap, a mirrored visor, and a plastic structure to hold them together. Some assembly required.

    Estimated delivery:
    Ships to: Anywhere in the world
    Manage your pledge

Funding period

- (30 days)