IR Blaster:Is it possible , could it be possible?

[stuartambient]

http://www.lirc.org/transmitters.html
http://www.lirc.org/improved_transmitter.html

On the about links, the first one , the simple transmitter, I built for about $6 in parts. The breadboard was the most expensive part. The second one, though I haven't tried it supposedly extends the range.

Seems to me from a functional point, that there is no difference between my actisys and simple transmitter. Just the fact that I had to solder some circuits. While I am not trying to interfere with the online store transactions, just curious if those other transmitters could, should, work.
They rely solely on the dtr pin (whatever goes through that).

Stuart

[jrhees]

Stuart,

I'll try to give an unbiased view of the difference.

The simple circuits like you refer to *can* very well work, but what they do is rely on the host PC to generate the IR signal. What this means is if, say, the IR signal consists of a 38KHz carrier, the host PC must spin in a tight loop toggling the DTR pin (which was designed for serial port flow control) at 38 *thousand* times per second.

In general, if the PC is running a real-time OS or is not busy doing other stuff, this works fine (you may as well burn CPU cycles on something, right?), but if you're running other stuff, this can lead to problems.

The solutions such as Actisys, etc., have a dedicated microcontroller which does this job, without involving the PC.

-Jon

[stuartambient]

The problem I have with the actisys is the constraints of the distance from the cable box. Is there any other units out there that can have a great distance?

Stuart

[justme]

Well since Jon didn't suggest the USB-UIRT, I'm guessing to try and keep referrals unbiased. I would suggest the USB-UIRT. It has an excellent transmision range and is a IR reciever to boot. It's available at the link above or at Frey's online store.

[ErsatzTom]

Along the same lines of questions, is their a low cost but reliable ir receiver only? I'm leaning toward using an ir remote for my STB client box. I like the rf remotes but I really want to be able to tie the volume keys to the tv volume for most things. Everyone seems to really like the usb-uirt but that seems like overkill. I'm positive I'll never need a blaster out there... all my tuners are on my server in another room. Anyway, if that is the best thing to get, then that is what I'll get but it seems like someone must be making a receiver only product.

t

[justme]

but it seems like someone must be making a receiver only product.

It's not all that low cost but there is the IRman. It's just a IR reciever and has been around for a while. I believe Sage sold it in there store, but I don't see it there now. I guess they stopped selling it after they added the USB-UIRT.

[stuartambient]

What is the range of the USB-UIRT , or should I go look at the page?

Also, as a side topic maybe, I'm a bit unsure about something. In my main entertainment setup (not very hi tech) I have the cable box, tv and vcr. The cable box coax is running into the VCR and then from the VCR into the TV. Now, because we haven't configured the VCR to be a "slave" to the cable box, it seems the VCR has a mind of it's own. I know we need to fix this but the current behaviour is something I'm trying to understand. If I say I want to tape something and schedule it through the VCR, and then change the cable box to the correct channel for taping it never works. The cable box always winds up changing the channel. What I'm not sure of is the VCR changing the channel through the coax connection (cause that wouldn't make technical sense) or is the VCR doing it through it's own blaster.
If it's own blaster, it has the perfect range, since it sits 6 feet away from the cable box and doesn't even point in the direction of the cable box.

Sorry, somewhat long winded here, but the point, it would be nice to not have to sit the blaster almost on top of the cable box. This is what I have to do with my Actisys 200L. It's not practical and for my intentions messy.

If the USB-UIRT could blast at a far greater range then the Actisys then great.

Stuart

[jrhees]

Since the ActiSys was primarily designed for IrDa, its range isn't all that stellar.

The USB-UIRT's blasters (it has two) are pretty high power. Many people simply let the IR permeate the room and bounce off the walls, etc. A good comparison (since there's a lot of variables) is to a very strong remote control.

-Jon

[justme]

it would be nice to not have to sit the blaster almost on top of the cable box.

To back up Jon's statement about range: You placement disciption is very analogous to mine. My USB-UIRT is 6-7 feet from my cable box and facing away from it at a 110 degree angle. I can say that the cable box always seems to respond. I don't know whether it's catching the siganl direct, even at the very difficult angle. Or if it's bouncing off a wall that is about 16 feet away and rebounding back to the box. Either way I can say it's seems powerfull as my Sony RM-AV2100, which is a monster remote(~4.5x7 inches).

As for the VCR to cable thing I can't what's going on there. Mine lacks a blaster and is slaved to channel 3 or the AV jacks. I should really take it out of my one signal path since I never use it anymore.

[stuartambient]

I think it sounds similar to my VCR blaster, since mine is not slaved to the channel 3.

Anyway who cares about VCR's

Maybe someone can tell me, and I could take it up with the company as well. What if I don't want the unit external ? Is there a way of getting it to sit inside a case, provided a notched a window for the led?

I suppose I'd have to change the wiring as well.

Stuart

[justme]

Anyway who cares about VCR's

Too true.

Is there a way of getting it to sit inside a case, provided a notched a window for the led?

I thought of putting mine inside my new Sonata case. This case is black and I was planing on reusing the purple plastic from the USB-UIRT as a window. One thing I may need to do is make use of the jack in the back of the USB-UIRT to add IR blasters. Since my new HTPC will actually be behind and underneath my cable box. I don't know if the USB-UIRT could send and bounce in that situation or not. Either way it's a nonissue with the expanxion jack. It would just mean a small black wire coming out for the extra IR blaster.

I haven't decided whether to pass the USB cable out the back of the case and into one of the rear USB jacks. Or to mod the USB cable and go with a fully internal mount on the motherboard's USB header.