Kent Fukuzura, Making Science Simple
Just about everyone’s bought a digital camera by now. But if you haven’t, or would like to learn more about how they work, this is the place to be! Using simple household items we’re going to build a digital pin-hole camera that will even take moving pictures!
You can, of course, use the body of an old analog camera, but why stop there? Let’s take the science down to its very roots and learn about optics while we’re there.
The Science:
A pin-hole camera works by having a box with a small hole in one end (the pin-hole) and a screen on the other. Light passes through the hole, which acts as a lens, and forms and image, upside down, on the screen. Traditionally, photosensitive paper is placed on the screen-end to capture the light, but we’re in a digital world now, so we’ll be gathering the image electronically.
Materials Needed:
You’ll need a shoe-box, and a pin to make the pin-hole. On the other end you’ll need to create a Charged Coupled Device (CCD), a sensor that will convert the light to electronic charges. CCDs are collections of light-sensitive diodes. Father should have a stack in his workshop–next to the furnace filters–but if not, you may have to salvage parts from the bathroom-cleaning robot we created earlier.
Combine the diodes into arrays that are sensitive to various spectrums of light. The more diodes per CCD, the better your resolution will be, so don’t cheap out.
Typically the CCDs are set to absorb red, green and blue light–just like your TV. When combined, they make up the part of the electromagnetic spectrum we can see. But nothing is stopping you from adding infra-red, ultra-violet or even gamma rays from your CCDs. Don’t be afraid to experiment!
Once your signals are converted to binary code it’s a simple matter of downloading them directly to your computer, or displaying them on a screen taped to the outside of the box.
Here’s a hint: your image will be upside down when it is collected by the CCDs. If you turn your monitor upside down they will appear upright!
You can also use your digital pin-hole camera to take moving pictures. Adjust your refresh rate and rewrite your software (I used C++) to accommodate a moving stream of images.
Combining the ancient pin-hole camersa with new CCD technologies allows you to not only create a serviceable camera, but learn about optics too!
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