IR emitter signal too strong for AM/FM tuner

[PaulD]

Just hooked up a Sony XDR-F1HD AM/FM tuner to my sound distribution system (HAI HiFi). I have not been able to get the IR signal to control the tuner (via the HiFi system) as it is supposed to do.
I did some web searches and found some info that indicates it is easy to overload the IR receiver on this model tuner with too much emitter power. I noted that the HiFi emitter specs say it drives the emitter at 100ma. Other tuner user have reported that they have problems with emitters at 70ma and have modified their emmitter setup to run at significantly lower levels to get their emitter to work with this tuner.
The tuner came with a remote and it works fine with the tuner one-on-one but if I try to control the tuner via the HiFi setup it will not work. I know the IR signal is reaching the tuner (via stick-on IR emitter over the tuner IR eye) because the IR emitter lights up brightly when I send a signal thru the HiFi. I tried to move the IR emitter to off-center from the receiver eye and I could very occasionaly get the tuner to respond but I never could find any off-center spot where it was anything close to reliable. I also changed the frequency setting on the RIM to make sure I was using a good IR frequency. Also made sure the HiFi passthru IR mode is turned on.

Bottom line...I am pretty sure I need to somehow attenuate the IR signal because it is overdriving the IR sensor on the tuner. So far, I have tried placing the emmitter a short ways away and have also tried placing various pieces of paper over the receiver IR eye to diffuse the signal. However, I have not come up with a good solution yet. Anyone have an idea on how to play with the emitter signal to adjust it to a level the tuner will accept?

 

[Michael McSharry]

Add single sheet toilet paper in front of the receiver. If it works then you can later get a more attractive T-paper dispenser for the entertainment room.

 

[Dave X10]

I have read (although never tried myself) that a couple layers of crinkled plastic wrap (saran wrap) can reduce the "brightness" of an IR signal.

 

[AutomateIt]

The toilet paper trick works for me from time to time when learning IR commands with my Ocelot.

 

[jmark71]

Another option is blue painters tape... stick that on and see if it helps... you can then 'paint' it black with a Sharpie and it will be unnoticable. The good thing with this is you can add additional layers of tape until you get the best response.

 

[mdesmarais]

Put a resistor in series with your IR emitter. . .

 

[PaulD]

Put a resistor in series with your IR emitter. . .

I have already tried the other suggestions with little luck. I thought this approach might work but was not sure how to do it. Rather than a fixed resistor, I was thinking a variable resister would be nice so I could play with the value to "dial it in". For the 2 legs of the emitter, does it matter which leg has the resistor. Also, what would be good value for the resistor?

 

[AnthonyZ]

Another old school technique is to use an opaque tape (electrical or similar) and fire through a pinhole in it.

 

[SteveQ]

Try putting the stick on emitter inside a small plastic vial; perhaps a prescription vial or a semitransparent film canister.

Steve Q

 

[PaulD]

No amount of filtering would work so I went in another directioon and I finally think I have determined my problem. The HAI HiFi system I am using to route the IR codes is limited to the 38khz and 56khz frequency range as determined by how you set a jumper in the modules that a sound source is plugged into. I called Sony's tech support to see if they could tell me what IR frequency is used by my radio. As you might guess, no one at Sony had a clue and I left empty handed. However, after a lot of web searching, I finally found a forum (remotecentral.com) where some users provided a link to the IR file used by the remote control. From that info I was able to determine that Sony used 40khz for IR control on this specific radio.
Looks like I am stuck with a frequency mismatch.
I sent an email to HAI support asking if I had any options to deal with this mismatch in their HiFi system.

 

[sleepovr]

I have the hi-fi system installed in my place and have yet to find a device that i can control through the hi-fi system.

 

[PaulD]

I have the hi-fi system installed in my place and have yet to find a device that i can control through the hi-fi system.

I have not tried anything else with my system but in the process of doing my analysis, I discovered that todays IR is not your Daddy's IR. Apparently, there are some new IR protocols out that have been created to carry more data in shorter burst. Some are also operating outside the traditional frequencies. Mfg's are adopting them to expand their capability but it is creating a lot of issues for the traditional solutions for IR blasters. I have Uverse TV and I see a lot of forum traffic looking for solutions to use IR blasters that can talk to the Uverse set top boxes. In that case, users report that different models of equipment in the same vendors line will work while other models will not.

Bottom line...it is a new world in the IR business. Newer equipment may not work as expected with traditional IR solutions. Test before you buy if it is critical to your application.