Smart Cap

Description

Smart cap is a completely open DIY project consisting of a wearable head mounted display. It runs a custom voice recognition software to support hands free engagement. It can be tailored for use in helmets, first person video recording, and can mimic functionalities of a google glass for under 80$.
It aims to intrigue people with the veritable wearable display technology and instructs them in detail about how they could build one of their own. The whole system runs on a raspberry pi with other peripherals like a 2.5" LCD screen, webcam, microphone, etc. Visit http://diyhacking.com/

Details

Head mounted displays are definitely the latest fad that's going around town now. You might have seen several wearable displays such as the google glass, and many others including virtual reality systems like the oculus rift. Head mounted displays are primarily used for video sharing, navigation, checking notifications, etc. However, several pioneers argue that the quintessential use for it have not yet been identified. But, if you ever wanted to build one for yourself from scratch, and are not willing to pay 1500$ just to experience its functionalities, then this DIY Head Mounted Display project is for you.

Head mounted displays usually consists of a high resolution LCD or any other display screen within about 5-10 cm in front of your eyes. For virtual reality systems, usually one split display or two identical displays are used for each of your eyes for the stereoscopic effect. Here, I am only using one miniature LCD display in front of an eye , hence called a monocular head mounted display.

In this system , in order to cope with the "Least distance of distinct vision" , which is about 15-25 cm , I have used an aspheric loupe magnifier lens having 5X magnification. This makes it possible for me to see the screen impeccably at about 5-6 cm from my eye. The display is also completely enclosed and insulated from outside light. The next part of the system is a normal USB webcam which was cannibalized to take only the camera and the microphone. All the plastic enclosures of it was removed, and the wires were re soldered to get a niche position for the camera and microphone on the cap. Furthermore, I used a raspberry pi running a voice recognition software I engineered , to ensure hands free operation.

Here, the LCD display acts like any other PC display. However, when certain voice commands are executed in tandem with the system, appropriate results or data is displayed in front of your eye. A few of those examples are : email , maps for navigation, Google search, YouTube, webcam recording and first person viewing of other cameras, etc. The raspberry pi integrated with this head mounted display thus has to be connected to the internet for performing these functions.

Components

1 × Raspberry Pi model B. Open source linux development board.

1 × USB Webcam A USB webcam with an inbuilt mic, I am using one from Iball.

1 × LCD Display A 2.5" NTSC/PAL LCD display.

1 × Headphone A headphone with mic.

1 × Aspheric lens A loupe magnifier with aspheric lens.

Project Logs

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Screenshots

Arvind Sanjeev • 07/20/2014 at 19:44 • 0 comments

Screenshots of some of the stuff running on the pi.

Project Blog

Arvind Sanjeev • 07/20/2014 at 19:02 • 0 comments

For instructions on how to build your own smart cap, please visit : http://diyhacking.com/diy-head-mounted-display/ ‎

Build Instructions

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Step 1

Step 1: Preparing the head mounted display enclosure

Cutting the sun board sheet for preparing the head mounted display enclosure
It is necessary that the display needs to be cut off from all external light sources to ensure a sublime viewing experience. Here, I have used plastic sun board sheets, the kind of sheets normally used for vinyl advertising, for making the enclosure. Cut out a piece of the sheet of length 21 cm and width 6 cm. Mark cross sections vertically at 6 cm , 10.5 cm , 17 cm and 21 cm as shown. Next, take a cutting knife with the length of the blade adjusted to be just 3 mm. On the lines earlier marked, cut through half way of the board. This will ensure, that the board bends properly to form a rectangular enclosure for the display.

Cutting half way through the sheet
Now, hot glue the circuit board attached to the display to its back. This will make it a rigid one piece display as shown. Next, apply fevicol SR glue or any other synthetic rubber based adhesive to the edges of the display and stick it to the sun board sheet as shown. Bend and stick all the edges of the display and finally seal it, to make the enclosure.

Sticking the enclosure to the display
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Step 2

Step 2: Attaching the lens for the head mounted display

Take outlines of your face for cutting off the enclosure's contours
The enclosure prepared , now has to be cut off in such a way that it fits snug with the contours of your face. Make outlines of your nose, your right eyebrow, etc using excess sun board sheets. Mark the outline obtained for the contours of your right eye on the prepared enclosure. Cut out all excess material on the four sides based on the outline. The ultimate aim being that the enclosure fits snug on your face.

Cutting the enclosure of the DIY head mounted display
Furthermore, take the aspheric lens and place it in front of the newly modified enclosure. View the display through the lens and wrap it using black insulation tape, such that only the LCD display could be viewed through it. The enclosure and the surroundings of the display shouldn't be seen while viewed through the lens. This ensures a better visual experience for the head mounted display.

Sticking the lens to the enclosure of the head mounted display
Stick the lens to the enclosure using the rubber adhesive as shown. Here, I have also spray painted the enclosure black, to prevent outside light from getting in.
Next, use some sponge or soft foam like material to stick on the front crevices of the plastic enclosure. This will make the head mounted display more comfortable while wearing it. Cut out the foam sections in the same shape as the four contours of the enclosure .Stick it to the edges using the rubber adhesive.

Covering the contours of the DIY head mounted display using foam
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Step 3

Step 3: Hacking the USB webcam
Take the USB webcam you have and remove its plastic enclosures. Remove the peripheral buttons, etc attached to it. Cut off the microphone attached to the circuit board. Next, salvage and remove a flexible mic enclosure with the mic from an old headphone. Now solder the new microphone terminals to the existing mic pads on the webcam circuit. Ensure, that the interconnecting wires for the mic have adequate length to be positioned near your ear. You can also use infra red leds with your webcam , so that your head mounted display will even have night vision ;).

Hacking open a USB webcam
Now, take the webcam circuit having the camera and stick it in front of your head mounted display. This can be done by preparing a bridge using the sun board pieces. Stick the webcam circuit onto this bridge. I have used hot glue for sticking it.

The finished DIY Head Mounted Display enclosure