top of page

diy Wearables

Head Mounted Displays

Originally Published on ActiveWirehead.com

February 18, 2015

In this segment of my DIY Wearables series I’m going to concentrate on ways to build a cheap Head Mounted Display(HMD) that you can use for a variety of platforms.

​

When I was a kid I used to watch shows like Beyond Tomorrow about cutting edge technology. Occasionally they would do a segment about Steve Mann or Thad Starner, two of the fathers of wearable computing. These guys have been building and using wearable computers since the 80’s and 90’s respectively. I always wanted to try it myself, but the display was a real stumbling block. I lacked the skill to build one from scratch and ready made displays were incredibly expensive. So I decided to shelve that idea for awhile.

Flickr - HMDs

Where to Start
Fast forward to 2013. When I first saw a Raspberry Pi I knew I was going to try and build a wearable out of it (more on that in the next article). At the same time, Google Glass had brought wearable computing to the forefront of the digital zeitgeist, so I decided it was time to take a fresh look at building an HMD.
A little research revealed that affordable video glasses had finally come to market, but they were still a little pricey for my limited budget at $150, and I wasn’t sure how I was going to convert one from being a set of glasses to a monocle display. So, as always, more research was called for. Finally I stumbled across a web page that explained how to use the monochrome HMD from a toy RC car as a composite display. I found one on Ebay for $30! The game was afoot.

When I got the car in the mail I was excited to start modding it, but I wanted to test its capabilities first so I spent a day or two just playing with the car and chasing my cats around the house. The display was pretty good for it’s cost, and even a low res monochrome display would work for my wearable Pi. The HMD was simple in design and would accept any composite video signal and display it as a slightly fuzzy black & white image. The Raspberry Pi has a build in composite video port, which is almost unheard of in modern computers, but the Pi designers wanted a user to be able to plug it into any TV and get started, just like the 8-bit computers of old, so the only tricky part would be adapting the toy car HMD to a Pi.

Flickr - 2014-03-12 07.46.jpg

This turned out to be easier than expected. The HMD used a 3 pole â…›” plug to connect to the remote control, just like a standard headphone plug. One pole was power (4.5v), one was signal, and one was ground. So all I had to do was connect the signal and ground to an RCA cable and connect some batteries to the power and ground poles. I had a headphone jack in my parts bin, and pulled the battery box out of a little flashlight that used 3 AAA batteries. The whole process was done in less than an hour and PRESTO, I had an HMD for my Pi.

Flickr - 2014-05-03 13.45.jpg

I was pretty happy with this setup and was having a good time experimenting with my own wearable computers, and then Adafruit published this little article. Here, they had figured out a way to use the components from one of the cheap video glasses I had looked at before to make a color HMD with a 3d printed chassis. I ordered the glasses, but still needed access to a 3d printer. I didn’t have one yet but managed to find a website that connects makers with local 3d printers. Before long I had the parts and was able to get the whole thing together in an evening.


Both of these HMD versions are easy to make/modify and don’t require any coding. The resolution is pretty low, but you don’t need very high res for an HMD monocle. They may not be little and slick like a Google Glass, but for a maker who wants to experiment with wearables on the cheap they are great displays.

​

copyright 2015 Jason Benson

bottom of page