Registered: Jun 2004
Location:
Posts: 3

Having problems with channel chainging gave me an idea. Why not open up the Sat or Cable receiver and solder a two conductor wire in at the IR receiver then into a simple optoisolator fed into a headphone jack mounted in the back of the case. In theory a patch cable could be used between the Tivo IR out straight into the back of the Sat/Cable box. This setup would allow your factory remote to control the device as normal but give Tivos IR blaster a direct interference free connection.
Has anyone tried this or see anything wrong in my theory?
Craig

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Registered: Aug 2000
Location: Nashua, NH
Posts: 7476

Seems simpler to me to insert a mini-emitter "in view" of the sensor. You're making some assumptions about the electrical characteristics of the receiver.

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Steve

One thousand three hundred thirty-three, zero

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Registered: Jun 2004
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Posts: 3

That's basically what an Opto-Isolator is a single device with both emmiter and sensor inside. There is no hardware assumptions, it would work with any device that the Tivo would have normal control over via IR. This is just a less cluttered way to get an interference free signal and without worry of proper alignment. A piece of two conductor wire, a case mountable jack, opto and patch cable is all that's needed. Opto's are less than a buck in most cases.

Craig

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Registered: Feb 2004
Location: Ontario Canada.
Posts: 2490

You are assuming the IR receiver in a cable or satellite box is just an eye. It is not. It is a unit which has an IR sensitive photo eye, plus an amplifer filter and detector. It outputs a logic low signal with the presence of an IR carrier (not just IR, but IR modualted at 35-45 Khz). At that, they are a sealed integrated unit you cannot have direct access to the eye.

To effectively do what you want, all you really need to do is filter out the carrier from the IR out on the Tivo (on the transistor side of the opto isolator) with a hokeinductor and capacitor.

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Tivo is Sony SVR2000, 80 GB HDD.
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Why do you keep rewinding that? Because with TiVo, I can.

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Registered: Jun 2004
Location:
Posts: 3

I've not looked but I bet your right. I forgot about the ir modules on the receive end. Do you know how the two leds are wired in the blaster (par. or Ser.)?


P.S. Did you mean Choke Inductor?

Craig

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Registered: Feb 2004
Location: Ontario Canada.
Posts: 2490

A: I don't know. I made one with just one LED,and it works fine.

B: Yes, a choke inductor, and capacitor, sized to snub the carrier into a DC waveform.

__________________
Tivo is Sony SVR2000, 80 GB HDD.
----
Why do you keep rewinding that? Because with TiVo, I can.

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Registered: Dec 2003
Location: NYC
Posts: 240

quote:

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Originally posted by 56Effie
Do you know how the two leds are wired in the blaster (par. or Ser.)?


Craig

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