IR remote control

[mustang]

Does anyone know of a website that has information on how IR remote controllers and receivers work? Have there ever been any NV articles on the subject?

[MrAl]

Hello,<p>How specific does the info have to be?<p>Basically, a ir LED puts out a pulsing
signal which the ir detector diode picks up.
Different codes are made by using a serial
code similar to a serial computer port.<p>I dont have the codes unfortunately <p>Good luck with it.

[mustang]

Thank you Al, I would like to find the IR code used by a VCR for record and stop. I would then like to build an IR transmitter for these two commands. I want to use the VCR as part of a security system. The range of the transmitter has to be about 25 feet and triggered by a PIR.

[MrAl]

Hello again Mustang,<p>The fastest idea i can think of is:<p>Pick up a cheap remote at the local
store, then open the case and wire up
the two required buttons to a CMOS analog switch.
Control the CMOS switch with whatever
you like (it will have CMOS logic inputs).
Alternately, use two relays.<p>Does this sound similar to what you are
trying to do?

[mustang]

Hello Al,
I was looking for something more compact. Your ideas are a good alternative. Thanks

[MrAl]

Ok great, but i was thinking you could also
remove the pc board from the unit and cut
away any part you didnt need, after you study
the switching arrangement. You would end up
with a chip and an ir LED and a small board
which you would have to reattach the LED or
mount it somewhere else. You dont have to keep
the whole remote intact.
If you decide to generate the codes yourself,
you will find you have to generate a carrier
square wave frequency and block out certain
pulses of that wave depending on code. There
might be 12 or more pulses to one code, of
which some will be missing for each function.
It's not a particularly easy task unless you have
a remote control chip.
If you have a scope, you can view the pulse train
out of the remote control by using an ir detector
diode. Pressing a button, you can then see
the pulse train as a voltage on the scope.
The serial code changes with each button.

[Smitty]

Here is a very good IR link http://www.epanorama.net/links/irremote.html ; I always use the Epanorama links for research.<p>Smitty

[MrAl]

Hello,<p>Looks like a very good link.
Perhaps we can find the codes somewhere next?

[wdc]

check the x10.com site. they have a vcr commander that will do what you want to do.
good luck

[mustang]

Thank you all for your help. I am checking everything out. Lot of good info.

[mustang]

I do have the x10 system. TV cameras, transponder, vcr commander, and Eagle eye detectors. I have found that in an outside environment the x10 system is ineffective. The detectors do not have the range to penetrate a building which is stucco. Has anyone had any luck in increasing the range of the detectors? I increased the supply voltage to 6 volts with no appreciable improvement. I am talking about a transmission range that is less then 50 feet.

[russlk]

The stucco is applied to a metal mesh, which is an RF shield. You would need lots of power to penitrate that.

[bodgy]

You say you would like the codes for a VCR RC. First you need to post the make of VCR.<p>
If it's a Philips then it'll definately be RC5 coding.<p>
colin

[mustang]

Hello Russ,
I have a steel garage door and a stucco building which contains the wire mesh as you say. I cannot figure out why my garage door opener works fine even from within the house which means it has to penetrate two buildings with wire mesh. The remote for the garage door operates on 9v. Is it the frequency that makes the difference?<p>Ray

[russlk]

For a frequency of 3.5gHz or higher the mesh would be quite porous, assuming it is like chicken wire. Window openings would pass much lower frequencies.