Intro: Glasses Mounted Video Display to One Eye - Turn Yourself Into a Borg
UPDATE 15th March 2013: I have newer better version of this now in another Instructable:
Believe it or not the real purpose of this project was not to play at being a Borg.
I needed to make some form of wearable head up display that also allowed me to work simultaneously, i.e. see what I was doing at the same time, to test the feasibility of a concept for a research idea I have had. I needed to for example be able to remotely watch a video screen with data on it and also later may want to view protocols, checklists etc on this "head up" display.
My interest in this is because I think wearable displays will be a valuable tool in hospital medicine, especially in anesthesiology.
The proper name for this is a monocular HMD (Head Mounted Display).
A number of video-glasses already exist for watching DVD's for example and these generate an image for each eye. The downside is that you cannot see your surroundings while wearing them.
So-called monocular (one eye) displays do exist but can be very expensive. I already had an old pair of Olympus Eye-Trek(TM) video glasses, which are (relatively) inexpensive and decided to hack them and embed one of the display units into a pair of workmans safety glasses.
Then, having made this display work, I used the innards of a wireless security camera / receiver combination to make the system work wirelessly and finally packaged all the circuits with appropriate batteries into a just-about-pocket-sized container.
This project might also interest the "wearable computer" fraternity. You could also attach an infra red camera to it to give yourself night-vison.
Step 1: Another View of Finished Glasses
Here is another view.
The box on the left contains a video receiver from a low cost security camera video transmitter / receiver combination plus batteries, plus the drive circuitry from the Olympus Eye-Trek(TM) video glasses.
The small circuit board and one set of optics from the video glasses are mounted in the safety glasses on the right.
These glasses may look bulky but it is actually better than some commercial systems out there, very light in weight too.
Step 2: Construction 1
A wireless hi-res colour camera CCTV kit from www.maplin.co.uk was used very similar to this one: Order Code: N12CX
This comprises a colour camera which will run off a 9V battery or mains. This has a radio transmitter in it which is claimed to be good for 100m. Also in the kit is a small video receiver. This comes with a 3 section lead that takes the audio (red and white plugs) and video (yellow plug) out of it to your television, or in our case the Olympus Eye-Trek(TM) glasses.
The receiver runs off 9V also and has a single circuit board in it which we will transplant later into our pocket sized unit.
Step 3: Construction 2
Here we see the boxed video receiver on the left and the unmodified Eye-Trek glasses bottom right.
Step 4: Construction 4
The video glasses have now been very carefully taken apart (v small cross head screwdriver required). There is a circuit board in the glasses themselves and also another one in a hand held driver/control unit that the source video signal is sent in to.
What you see here is the small circuit board from the glasses themselves and ONE of the two video display units. The second has been simply unplugged from the circuit board.
A backlit LCD screen projects an image down from above your eye into a prism arrangement that redirects the light into your eye.
I have tried to give you some idea of what the view looks like although tricky to photograph - it is better than this in real life.
Beware, any dust and debris on the or near the LCD screen will be very visible when you look through the prism - keep everything clean and no fingerprints on the optics!
Step 5: Construction 5
Here is a view of the tiny camera, the receiver and the hacked internals of the video glasses waiting to be transplanted into one lens of the safety glasses.
Step 6: Construction 6
Here the prism unit has been grafted into the lens of the safety glasses.
The lenses of the safety glasses are polycarbonate which means you can cut a square hole out of one of them with a Dremel with a cutting disc in it and the lens will not shatter.
Measure twice, cut once. I marked up the square hole using black insulation tape strips and then moved them around over and over until exactly right before cutting anything.
I glued thin clear plastic to sides of prism and then cut them down little by little so that when they were stuck to lens of glasses the prism was held at exactly the right angle for you to see the screen properly while wearing the glasses. This stage needs to be done very slowly and carefully in small increments to get it right.
I used plastic glue very sparingly in places and a hot melt glue gun also (with care).
Once the prism unit was mounted I reassembled the display components back into the top of it. It all clips together although very delicate. Tiny blobs (and I mean really tiny) of hot melt glue stop it coming apart when assembled.
Step 7: Construction 7
Here we see the prism mounted into the glasses and the LCD display plus backlight reassembled onto the top of it. The circuit board is attached by a fairly short pair of ribbon cables. These are so tiny I did not dare lengthen them so the circuit board is now mounted on side of prism unit. It would have been neater to mount it on side arm of the glasses but I did not dare cut into the ribbon cables as they are so delicate.
The next problem is how to box this up neatly, multiple curved surfaces - really tricky.
Step 8: Construction 8
Here is a better view of the circuit board. Very fragile, masses of components on it. Easily damaged.
Step 9: Construction 9
In the end I used two very small plastic hobby electronics boxes and Dremelled them down carefully until they fit the structure and against each other. Gaps filled with "liquid metal" which is just an epoxy based filler and then all painted black (next picture). Again very fiddly, need to go slowly to avoid mistakes.
Step 10: Construction 10
Here the enclosure has been painted black.
Box on left contains the circuit board from the video receiver, the circuit board from the hand held control unit for the Olympus video glasses, a 9V battery for the video receiver and 6X1.2V rechargeable batteries to power the Olympus Eye-Trek(TM) circuits.
My aim was to make this box pocket sized whaich I have just about managed to do.
Step 11: Construction 11
Here is the control box opened up:
Top left: 6 X 1.2V NiMh rechargeable batteries to drive the Olympus Eye-Trek(TM) circuit board.
Middle left: 9V battery to power the Video receiver circuit board.
Middle: Two circuit boards one above the other separated by an insulating layer of clear hard plastic.
Upper board is the one from the video receiver.
Lower board underneath is the one from the hand controller of the Eye-Trek glasses.
There is an on/off switch for each board.
I made up a cable to take the "video-out" signal from the receiver to the "video-in" port of the Eye-Trek glasses (this also included the audio too). If this is unplugged from the "video-in" it allows you to run the display from a cable fed video signal if you want to, with the video receiver unit switched off.
Step 12: Finished
Here it is finished.