The zombies are closing in, it’s dark outside. You need to make a break for it but don’t want to get swamped by shuffling, brain hungry ninjas…

This is the exact situation I didn’t find myself in when I built these goggles.

Whilst these do enable you to “see in the dark” they are not the passive light amplification goggles used by the military and other professionals. These work in a very different way.

There is an array of infrared LEDs emitting light in the near infrared spectrum; the wavelength is slightly longer than what should be able to be perceived by the human eye, just past the red end of the visible light spectrum.

This light is used to illuminate the surroundings in a way that is not detectable by people (or ex-people) using the naked eye. The infrared light that is reflected from the environment is captured by a CCD and converted into an image in the visible light spectrum that is displayed on a screen in front of the user’s right eye.

Capturing the infrared and displaying the output is the most complex part of the process fortunately there is a convenient shortcut one can take.

I have several old yet working digital point and shoot cameras in my bits box, one of which I chose to cannibalise for this purpose.

The CCD (Charge Coupled Device; the image sensor in a digital camera) in a camera needs to be sensitive light in the visible spectrum but in most cases is also sensitive to light just outside of the visible spectrum, this includes near infrared.

However in order to preserve image quality for visible light, the lens assembly of the camera will contain an infrared filter to greatly reduce the amount of infrared light that reaches the CCD.

So, with this in mind the first step was to remove this filter in order that the CCD will be able to pick up the infrared light better. Unfortunately I neglected to take photos of this process, but here is an annotated picture to help describe it.

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Behind the metal cover at (A) the light enters the camera lens; it is bent through 90 degrees and travels down through the focussing array to the CCD at (C). (B) Marks the approximate position of the infrared filter, it was just above the CCD in this instance.

I removed the unnecessary components from the camera to save space and weight, the flash + daughter-board, some of the controls and small speakers. It was necessary to power on the camera after removal of each component and make sure the device would still boot. The camera firmware would check to see if certain components were present and would fail to boot of some were missing. In the case of some of the superfluous controls i was able to identify which pins the hardware controller was monitoring and just solder on a small jump patch to trick it into thinking they were present.

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I decided to use a pair of 3D glasses from the cinema seeing as I had several pairs lying around (they allow you to take them home). I poked out the polarising filters tried to get an idea of where to put the camera + screen.

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The camera runs at about 5v but the LED array requires 12v, furthermore, the combined current of the two meant that my little desktop power-supply couldn’t manage powering both. So here, during testing I’m using my bench supply and the DC power-supply from an Xbox360 HD-DVD player.

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Later, as you can see, I didn’t have any spare battery holders to hand at the time so I soldered a bunch of AAs together and hot-glued the lot, finally giving them a liberal wrapping in yet more duct tape.

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As it turns out, the screen needs to be a considerable distance from the eye in order to be able to focus on it; this meant I had to distance the camera body from the frame of the glasses somehow. Kitchen roll and Duct tape proved effective if not pretty.

You can see the infrared LED array attached to the left eye of the glasses. When turned on you can actually see a very faint glow of red light coming from them, I’m not sure if that is because the human eye can perceive very bright infrared light or if the LEDs produce some light in the visible spectrum too.

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Rear view:

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The result works fairly well, the image below is of Optimus Prime stood on my sofa at the other end of the room. The picture is out of focus, the goggles are actually reasonably crisp.

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So there we have it, total cost of the build to me was ~£9. The zoom and autofocus functions of the camera remained intact, despite the refractive index of the lens assembly changing as a result of the removal of the infrared filter so goggles are actually fairly flexible in use and I was at least able to wander around the house in the pitch black with no issues at all. I was worried that the weight of the camera sticking out in front of the frame would unbalance it too much but the weight of the batteries counterbalanced it well.

Woefully impractical and quite horrifically ugly, but it was a fun build 🙂

 

High resolution gallery:

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