Compared to some animals, humans see poorly at night and need special devices to make them see better in the dark. You may have seen the night vision devices that the military uses to see things as clear as day at night, or those special episodes on TV where the cameras are fitted with night vision so even if there is insufficient light, the camera can still pick up the action. Some night vision devices when used in the dark may have those greenish displays, while some video cameras may display images in black and white. There are several ways to replicate these night vision devices with objects that can be found at home or in buying materials that would cost you very little.
- Prepare a classic flashlight. There are different types of flashlights now on the market, like LED flashlights, or flashlights fitted with extremely bright bulbs. But for this project we’ll use the classic flashlight with a regular incandescent bulb. You can use a small portable one or the big one that looks like a search light.
- Acquire a few sheets of polarizers. On LCD screens you’ll find these plastic sheets on the screen. These actually help create what you see on the LCD display. Take for example those old cell phones with black and green displays, or those digital watches. They all have LCD displays, and the thin plastic sheets on them help display numbers and letters on the LCD screen. Find a few from old LCD displays big enough to cover the flashlight's window. Take 4 or 5 of these polarizer sheets and stack them on top of each other, but they have to be crossed in such a way that when the sheets cross on top of each other it turns black. When the sheets are stacked and blacked out, you can now attach this on top of the flashlight’s window with transparent tape.
- Try out the night vision device. Now that you have the classic flashlight fitted with polarizer sheets you can start testing it. The light from the classic flashlight must not pass through the polarizer sheets. If you turn on the flashlight and you physically do not see any light coming from it then you are successful, but try looking at it again, this time through a video camera. Video cameras these days can pick up infrared light, and this is what you turned your classic flashlight into. If you don’t see the light emanating from the flashlight through your naked eyes but do see it through a digital video camera then the project is a success. What you did to the flashlight is turn it into an infrared flashlight with the polarizer sheets, your eyes won’t see the light but the video camera will.
Wait until dark to test out your night vision device. In the dark, point your infrared flashlight anywhere and follow while looking through your digital video camera’s display.