Saturday, August 24, 2013

IR Light from a remote control

Reminder: These are NOT instructions. Do NOT try this out yourself.

UV + Visible + IR
Infrared is the spectrum of light that's just above the visible spectrum that people see in. And visible is just above the ultraviolet spectrum that gives everyone a tan and skin cancer. From what I've read, the last color visible before crossing into ultraviolet is blue-ish, and red is the one before going into infrared.

Regardless, people generally can't see the light that comes out of common remote controls. These are the crappy infrared remotes that have come with televisions, cable boxes, DVD players, VCRs, and even fans for the longest time. The LEDs or bulbs at the front of the remote are where the signals are sent to the sensors on the TV.

As a kid, I used to screw around and see which way I could point the remote and still have the TV respond. Surprisingly, a lot of directions including opposite the TV and to other directions worked. I'm guessing that the light got reflected.

Seeing IR with a digital camera
I didn't realize until a few months back when googling random things that the light signal from these remotes is actually visible -- okay, not really, but a digital camera's sensor does pick it up. Tons of videos on YouTube available.

Remote Rant
I tried this with a universal remote for the cable set top box and TV. It can be programmed to work, for the most part, with both the cable box and television. However, I've noticed that a lot of people in my house, and some visitors, can't figure out how to get it to work.

People hit the power button, then put it down or move it, so that the sensor isn't pointed at the television and cable box after a second. Problem is that the remote controls we have from the same cable company don't send out the signals for both items at the same time. It sends the cable box "on" signal first, stops a second, and then sends out the television "on" signal. These signals correspond with the blinking red lights. For some reason, the two red lights blinking at separate times doesn't show up in the video I made. However, you can still see the separate signal pulses.

Oh, and I hate these IR remotes. We have Wi-Fi and Bluetooth now. It used to be so much funner and easier to make the TV do things when I still had my Playstation 3. The controllers used a radio signal that didn't need to be pointed in any particular direction. I'm guessing it's a cost saving and cross-generational compatibility measure that TVs still use infrared.

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