IR Remote Control!

[-NEO-]

I was just thinking! How does a remote control work? Im talking about the infrared part of it as used on most TV!

For example:

Everyone knows that you do not have to point your TV remote at the TV to change the channel! This is because the Beem bounces off the walls for a few seonds until it hits your TV's IR reciever!

The question i am asking is:

Why dont the IR beem bounce back off your TV's IR reciever, hit another wall then bounce back towards your TV to change the channel again?

How come it bounces off the walls, but not the TV?

If id did do that, your TV would change channels twice!

Anyone know anything about this?

[Mule]

I don't know about the bouncing off the walls bit but it's sending out a light beam, so it's going so fast that you wouldn't notice.

[Shambles]

I think it's just plain magic.

My remotes don't work if I don't point 'em at the units.

[Shotgunjim]

Too much to think about... i press a button and Im watching footy.. press another and Im watching pr0n... Im happy :thumbs

[tagy]

the tv probobly ignores repeat signals within a few ms of each other. who knows..

[maverick_15]

i dont think it bounces off walls, just reflective surfaces. if thats the case itd have to be set up pretty accurately for it to come off the telly, off another reflective surface and back to the telly

[TwoPlAnKs]

it works by sending out pusles, each pattern refering to a different button on the remote

and they dont work if you point them the wrong way, and they dont reflect off stuff to a suitable extent

its just a beam of light that is outwith what we can see - if you shine an anglepoise light at one side of a room, the other side will certainly be lit up but compared to where you pointed it, the dark side will be pretty dark.

also if it did reflect you wouldnt have to wait a few seconds for it to hit the receiever, in fact for it to take exactly 2 seconds you would need to be standing by the tv and pointing the remote at the other side of the room, the room being 300 million meters across, or about 186 000 miles.

edit: i decided to further take the piss and point out that you could go from london to austrialia, and back, 18 times in 2 seconds if you traveling at the speed of light.

[xdir]

[QUOTE=TwoPlAnKs]it works by sending out pusles, each pattern refering to a different button on the remote
QUOTE]

What a load of rubbish, everyone knows that remotes work by magic, when you press the buttons invisible hands shoot out and press the buttons on the TV. . . . oooh these mushrooms are awesome.

[Shambles]

everyone knows that remotes work by magic, when you press the buttons invisible hands shoot out and press the buttons on the TV

Like I said.... "magic" :thumbs

[-NEO-]

they dont reflect off stuff

Light does reflect off surfaces tho! Thats how we see things!

Thats why we can see objects when its light, and when its dark we see nothing!

Anyway, im no expert! :nowords:

Just found it intresting... :thumbs

[TwoPlAnKs]

yes light reflects off surfaces but not to enough extent to make a tv change channels. also as someone said the chances of the beam hitting the tv are slim.

[Cenus_]

Infa-red remotes go out in a straight line (like a laser) but when the reflect of a surface they come out like a cone (like a torch) so when you hit a wall with the 'laser' it pretty much fills the room and hits the TV's sensor at some point. Any further reflection becomes to weak to affect a change. So, it does reflect off the t.v but directly away from it, therefore another reflection wont change change the channel twice. :thumbs

[Mule]

yes light reflects off surfaces but not to enough extent to make a tv change channels. also as someone said the chances of the beam hitting the tv are slim.

I think you need new batteries in your TV remote, it works when I point mine at the wall opposite the TV. TV remotes don't send out a thin beam, the light they emit is quite widely spread, that's why you don't generally need to point the remote at the TV. (unless it needs new batteries, but then you just push the buttons harder).

[slartibartfast]

WTF are you all talking about, beams of light, pfff. There's no beams of light coming from my remote.

[chubblies]

I was always led to believe that IR is basically the same as having a normal LED, it is just invisible to the naked eye, and that it does not need to be directly pointing at the receiver, the TV will just "see" the light just like we would see a flashing LED regardless of where it is pointing.

On another note, ALL light is actually invisible until it reflects off something, the only reason we see it is because it is illuminating the surface of something or reflecting, but the actual "light" cannot be seen...

[TwoPlAnKs]

Infa-red remotes go out in a straight line (like a laser) but when the reflect of a surface they come out like a cone (like a torch) so when you hit a wall with the 'laser' it pretty much fills the room and hits the TV's sensor at some point. Any further reflection becomes to weak to affect a change. So, it does reflect off the t.v but directly away from it, therefore another reflection wont change change the channel twice. :thumbs

indeed

On another note, ALL light is actually invisible until it reflects off something, the only reason we see it is because it is illuminating the surface of something or reflecting, but the actual "light" cannot be seen...

lies! light is the only thing we can see.

[chubblies]

lies! light is the only thing we can see.

So look around your room now then...The only light you can see is what is being reflected by furniture, or whatever, you cannot actually SEE the light travelling across the room. Just like in nightclubs, a laser being shone across the room is invisible unless it is in a smokey atmoshere, and the smoke particles are being illuminated by the light, but the actual light energy IS invisible:tongue

[tagy]

So look around your room now then...The only light you can see is what is being reflected by furniture, or whatever, you cannot actually SEE the light travelling across the room. Just like in nightclubs, a laser being shone across the room is invisible unless it is in a smokey atmoshere, and the smoke particles are being illuminated by the light, but the actual light energy IS invisible:tongue

yeah i agree.

[Mule]

So look around your room now then...The only light you can see is what is being reflected by furniture, or whatever, you cannot actually SEE the light travelling across the room. Just like in nightclubs, a laser being shone across the room is invisible unless it is in a smokey atmoshere, and the smoke particles are being illuminated by the light, but the actual light energy IS invisible:tongue

He's right, you can only see light once the rays have been altered by hitting an object, which is why space is black.

[Mule]

I was always led to believe that IR is basically the same as having a normal LED

That's right too, it's not a laser beam