UIRT Flashing while computer is off

[ewingr]

My computer is shut down. I am surprised to see the UIRT still powered, as the computer is not in Standby.

I'm sitting here watching the urit flash constantly. Is that normal? I wonder what could be causing that.

I do have wireless networking in the house.

Could this be causing some of the issues I have with having to press my remote button repeatedly for it to work?

[jrhees]

Hmmm that's a new one. My guess is that your PC is still [partially] powering the USB-UIRT but with not enough voltage. I assume the led does not continuously flash when the PC is on, correct?

-Jon

[ewingr]

That is correct. Allthought it does occasionally flash when I'm not pushing any remotes.

[bliss]

My unit was doing the exact same thing. What I found was that my Radio Shack 15-2117 IR/RF command center was "leaking" an IR signal enough for the USB-UIRT to pick up the signal. Repositioning the command center fixed the problem.

I was hoping to somehow connect the output of the IR/RF command center to the input of the USB-UIRT to give me an RF solution. (Possible future project)

[Guest]

Did that leaking signal cause you any problems?

I have a Terk IR, uh, what do you call it, repeater? Poor man's solution to RF. I have a receiver in one room that forwards to the terk unit in my media room which repeats the signal out to my devices in my cabinet.

[bliss]

Did that leaking signal cause you any problems?

The leaking signal never caused any problems with my equipment, (tv, stereo, etc.), but I could never get it to work with USB-UIRT with any constant results. The IR code was changing constantly. I deemed this to be the fault of the repeater not the USB-UIRT as it works perfectly with the remote itself just not the repeater.

I tried every position configuration imaginable including; across the room, next to the USB-UIRT, and the external IR transmitter. Somtimes it would work, most times it would not. I had hoped to take the output on the repeater and hook it directly into the USB-UIRT but because of the problems I encountered I decided against it. (for the time being )

My guess is that the Radio Shacks IR/RF repeater unit's power source is not very clean (ie. noise) but thats just a guess as my electronics knowledge is a little rusty.

[jrhees]

Usually the problem with repeaters is that they create a *lot* of background IR noise. Here's why:

A repeater is not 'smart' -- i.e., it does not actually decode nor generate IR codes. Instead, it simply acts like an infrared 'microphone/speaker' combo. So, *any* IR energy it sees in one room it blasts in the other. There's a *lot* or IR noise floating around, from the Sun, heat sources, lights, etc. etc.

A good analogy is to think of putting a microphone in one room and the amplifier/speaker in another. Then, turning the volume way up. Sure, you'll hear someone talking in the other room fine, but you'll also amplify the air conditioner, and any other noises in the room.

IR Repeaters usually work fine despite this problem, since the equipment being controlled knows exactly what IR code and format to look for. So, even though your TV's IR reveiver sees a lot of IR 'noise', it also knows when the 'right' IR codes are coming in.

The USB-UIRT, on the other hand, does not have this advantage. While it *can* make an educated guess on what is an IR code and what is simply noise, it *cannot* be nearly as selective since it is universal and needs to see all sorts of remote brands and protocols. Therein lines the reason why you see all sorts of codes being generated when the IR repeater is in use.

Hope this helps to clarify things...

-Jon

[bliss]

@jrhees

Thanks for the explanation.

The repeater I was referring to is not actually a repeater but a box that comes with the Radio Shack 15-2117 remote. The remote has a small transmitter that sends an RF signal to the box which then generates/sends the appropriate IR signal out to your equipment.

The box does not have any IR receiving capabilities.

The box should not be emitting any IR signal until it receives the appropriate RF signal.