Our eyes can only see a portion of the electromagnetic spectrum, and infrared light—which has lower frequency, longer wavelengths, and less energy per photon than red light—is just outside the range of the light we can see.
Infrared light is often divided into the near infrared, which is closest to the visible spectrum, and far infrared, which is emitted by warm objects.
To send a signal to a television, remote controls often use a diode that emits light at around nanometers in wavelength, which falls into the range of near-infrared light. Some digital cameras have filters to block near-infrared light, but most can detect it. It shows up on the screen as if it were visible light.
When you press a button on the remote control, the camera may show a pulsing light emitted by the remote. The pulses are coded to control the television. Infrared light and visible light interact with materials in different ways. Near-infrared light passes through clear glass and will reflect off metal surfaces, including mirrors.
Infrared light passes through most black plastic trash bags, so you should be able to control your television even with the remote covered in plastic. Does that make sense, Stamps? We are undergoing some spring clearing site maintenance and need to temporarily disable the commenting feature. Thanks for your patience. Drag a word to its definition.
You have answered 0 of 3 questions correctly and your score is:. Want to add a little wonder to your website? Help spread the wonder of families learning together. We sent you SMS, for complete subscription please reply. Follow Twitter Instagram Facebook. How does a remote control work? What types of signals do remote controls emit? What is the primary benefit of radio-frequency technology?
Wonder What's Next? Explore the following activities with a friend or family member: Need some help visualizing what you learned in this Wonder of the Day? Ask a friend or family member to watch with you! How many remote controls do you have around the house? Take a walk around and see how many remote controls you can find. You probably have one for your television and movie player.
You might also have some for toys and other electronic gadgets. How are the various remotes similar? How are they different? Do you own a universal remote control that operates multiple gadgets? How about remote control apps on a smartphone? What would life be like without remote control? Find out! Infrared light is in the invisible portion of the electromagnetic spectrum.
An IR remote control the transmitter sends out pulses of infrared light that represent specific binary codes.
The IR receiver in the TV, stereo or other device decodes the pulses of light into the binary data ones and zeroes that the device's microprocessor can understand. The microprocessor then carries out the corresponding command.
To get a better idea of how the process works, let's take a look inside a typical remote control -- the universal remote that came with the author's digital cable box. The basic parts involved in sending an IR signal include:. To find out more about the parts on a remote-control circuit board, check out Inside a TV Remote Control.
You can do a quick experiment to prove to yourself that there is a light in the end of your remote. You will need a TV remote control and a digital camera for example a phone camera. Turn the camera on and point it to the end of your remote control and press any button. Can you see an LED light up? You may even see it flashing. If that is the case try a different camera.
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