IR Blaster
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What's An IR Blaster?
An IR Blaster (http://mythblasterz.gotdns.com/) is simply an IR (Infrared) emitter. It's an LED that emits light in a frequency range that you can't see with the human eye. Infrared is commonly used in consumer electronic devices to remotely control certain functions. An IR blaster is simply an IR emitter that hooks up to your PC so that your PC can send IR signals/commands to your Home Theater equipment, generally your digital cable box or satellite receiver.
How Does One Use An IR Blaster?
People with digital cable or satellite dish set top boxes need a way to have their external PVR's (in this case PC PVRs) control the set top box.
An IR blaster acts much in the same manner as your existing digital cable (or satellite) IR remote control. When you press a button on a remote control it sends a little IR signal to your digital cable box to change the channel.
An IR blaster sends (blasts!) the same IR signals (once configured of course ;) ) to change the channel on the STB (Set Top Box).
So lets back up a minute. You'll need to connect the video and audio out from your digital cable STB or satellite STB... (Preferably with S-Video... but you can use video composite or coax/RF) to the audio and video inputs on your tuner/encoder card.
You'll also obviously have your IR blaster hooked up to your PC, and the IR emitter aimed up close (for most IR blasters, some are stronger than others) to the IR "eye" receiver on the STB.
Now your PVR software will know what time your favorite show is on and on what channel. When it's time to change the channel on the set top box it will send the command to the IR blaster which will in turn "blast" the IR code/sequence to tell the STB to change the channel e.g. it'll send "5 0 3 <enter>" command to the STB just like if you typed the numbers 5, 0, 3 and enter on your regular remote control, but the IR blaster and your PVR software do this automatically without your intervention/presence!
Editor Note: A diagram would make this easier to understand ;). Anyone want to whip one up?
Alternatives
But I don't want to use an IR blaster you say! It's a little slow to change the channels and if my cable or satellite box shuts off I just pvr black screen!
Well certain folks with certain STB (Set Top Boxes) can utilize a serial connection to control their Motorola digital cable box or certain DirecTV satellite receivers (example: DirecTV D10 Serial Tuning HowTo ). This is the preferred option if available, with IR blasting being a fall back/more common method to control external set top boxes.
IRDA Boxes
Unfortunately some of the Pace NTL/Telewest boxes use an infra-red signal protocol based on the IRDA standard. This allows wireless keyboards etc to be used for surfing the web etc. However, the unusual protocol means the humble blaster wont work on it's own, a device is needed to convert the IR signals from the blaster into IRDA signals for the box. www.redremote.co.uk make such a device (see their site for where to buy) and their website contains a lot of information about this and identifies many of the boxes which use IRDA.
IR Blaster Vendors
- Mythblasterz (http://mythblasterz.gotdns.com/)
- http://www.usbuirt.com/
- http://www.redremote.co.uk/
- The Hauppauge WinTV PVR 150 Retail Edition includes a remote and a servicable IR blaster included.
