Help, can't find my IR receiver window!

[electron]

I want to use stick-on emitters with my JVC AV-56P585 (or AV-56P575, not sure which model it is) 56" rear projection unit, so I can control the TV using my computer, but I am unable to locate the IR window. When I scan the entire surface of the TV by holding my remote about .5" away from the surface, the remote will only work when I am holding it front of the glass. I tried the speaker grill, every other spot, but no luck. Is the IR receiver hidden behind the actual glass (which would mean I can't use the stick-on emitters)? Thanks!

 

[Guy Lavoie]

Yes, many projection TVs have the IR receiver inside the cabinet and reflect the received IR signal down to the sensor using its mirror. In cases like that, you need to open up the cabinet and visually locate the IR receiver in order to be able to sick on a mini emitter.

 

[electron]

The TV is still under warranty, so I can't open it up. So much for that idea :/

 

[Guy Lavoie]

A lot of people who want to automate projection TVs come up against the opening up vs warranty issue. How about using a IR blaster?

 

[electron]

I am not sure where I could mount it, my living room is pretty open.

 

[Guy Lavoie]

How far away is the opposite wall? I'm using a blaster that's about 18 ft away without a problem. You can test a potential mounting location by holding your remote at the same spot pointed towards the TV and trying it.

 

[smee]

A good blaster may fill the room with IR. You may not need to worry too much about placement.

You could also consider trained mice and a small hole in the TV.

 

[electron]

What would be considered a good IR blaster, compatible with an Ocelot?

 

[Guy Lavoie]

Well, I built my own. Its a simple circuit using just one transistor and a few other easy to get parts. Here is the information:

http://www.hometoys.com/tips/tips20.htm#Entry%207

 

[Rupp]

Dan,
You know I use the powermids. They work exceptionally well for me. This weekend we had to move the furniture in the living room around to have the flooring replaced so My powermid is directly to the left of my TV and it still controls it perfectly.

 

[electron]

The powermids might work, but that means I have to invest more money into a low priority project, which would mean a lower WAF But it isn't a bad idea at all!

Guy, what distances can you get with that circuit?

 

[Guy Lavoie]

I currently get about 20 ft. I haven't tried it any furthur (there was no need to) but others who have built it have gotten 25 feet or more.

 

[electron]

Will one of these work for power?
http://www.automatedoutlet.com/product.php...&cat=103&page=1

I really want to build one of these on my own, but I only have a RadioShack near me. Can you tell me if RS sells a compatibe transistor I can use? Your schematic also seems to mention the use of a 15 Ohm resistor, am I reading that right? Thanks!

 

[electron]

I just made a quick stop at RadioShack and got the following parts:

High-Output 5mm Infrared LED (276-0143)
MPS3904 Transistor NPN silicon (276-2016)

I already have all the resistors, did I miss anything else (or did I get the wrong part)?

 

[Guy Lavoie]

Yes, those part should be ok (both of your links point to the same part but the MPS3904 is the right description for the transistor). Pretty well any source of +12 vdc can be used, as long as it is seperate from the supply for the Ocelot or expansion modules.

The 15 ohm resistor is a rough approximation. It will probably work ok with a 10 ohm (and put out a stronger signal). If you want to be safe and stick to 15 ohms, you can use three 10 ohm resistors to create it, by putting two of them in parallel to create a 5 ohm and then put it in series with the third 10 ohm part, giving 15 ohms.

Make sure you get the polarities and transistor orientation right and it should work right away.