Wich IR receiver to use?

[Luc]

Somebody reported poor response with his remote and UIRT2, max working distance was 4 meters. He was using a 36KHz receiver.
My setup with a 38KHz receiver still works at 8 meters, maybe further but I am with my back against the wall.

I had a look at the datasheets for 2 receivers and found the following:

TSOP17XX: if you are 2KHz off it's center frequency, sensitivity drops to 70%, for 4KHz off it drops to 40%.
SFH5110: 2KHz off is 50% and at 4KHz off only 25% sensitivity left.

So using a 36KHz receiver with a 40KHz remote has very poor reception and a 2KHz difference is not optimal neither.

Is there an easy way to know the modulating frequency for a specific remote? Does somebody has more info on this or is it on the net somewhere?

Luc.

[el84]

I found a site that has an incredible amount of information on specific remotes and remote-controlled gear:
Remote Central (http://www.remotecentral.com/)

That site has a whole section dedicated to files for the Phillips Pronto/ProntoPro. There are thousands of config files (CCF files) available for download there! One little problem: the files are in a proprietary binary format.

First step is to learn a little about the CCF format:
http://www.remotecentral.com/features/irdisp1.htm

Next, grab a utility that will decompile or display contents of a CCf file:
http://www.remotecentral.com/files/util.htm

Note: IMO, "CCF Tools" was the most useful utility for viewing CCF file contents.

Then, go grab some CCF files and start decompiling :)
http://www.remotecentral.com/files/main-ccf.htm

Should be possible to convert CCF file data into a format usable with Girder/UIR/UIRT. Wish I had the time to write that program. But, I haven't even finished building my UIRT yet!

[kari]

Is there an easy way to know the modulating frequency for a specific remote? Does somebody has more info on this or is it on the net somewhere?

I'm afraid that I only know the method I used, and that could hardly be called easy :). I opened up my remotes (which can be difficult or even impossible to do without damaging them) and hooked an ocilloscope to the output diodes. Even that way, getting accurate readings was difficult due to the intermittent and complex nature of the waveforms, but my estimate was usually closer to 40 than 38 kHz.

I am using a 36kHz SFH5110, as it was the only type I could lay my hands on when I was building my UIRT. It works at distances up to about 3 meters, provided you point the remote straight at the UIRT. I am, however, thinking about ordering a 38 or 40 kHz part to improve reception. Going by your data (thanks for that b.t.w.), TSOP17xx seems better than SFH5110, as it can handle a greater bandwidth, but does anybody know if there is a major difference in the basic sensitivity of these parts? I.e. is it possible that SF5110 at 50% is more sensitive than TSOP17xx at 70%?

-Kári.

[Luc]

Kari,

I can't find enough info in the datasheets to determine wich one has the best sensitivity.
I was looking for the carrier info so that everybody could find the frequency for their remote and choose the appropriate receiver without the need for an oscilloscope.

el84,
thanks for the info, I wonder why my searches didn't find this site.


The remote central site has very good information, the best is that those CCF files contain the carrier frequency.
The file generated by CCF Tools has the carrier as a hex value, thus calculation is required. CCF2EFC creates a file with the calculation already done.
Care should be taking when using these files, some of them are a "scene setup" like "Watch DVD" and multiple devices are controlled like the room lights, amplifier, DVD...

[Muyz]

I just built a UIRT2 and also had problems with the receiver @ 36 kHz: no more that 3 meters between receiver and transmitter. After replacing the receiver by a TSOP1738, I now have far better results: >10 meters.

[kari]

Which type of 36kHz receiver were you using? TSOP or SFH5110?

-Kári.

[Muyz]

Which type of 36kHz receiver were you using? TSOP or SFH5110?

-Kári.
Unfortunately, I do not know the brand/type of my former receiver. I am quite sure it wasn't any of the ones you mention.

[kari]

Ok. Thanks anyway.

-Kári.

[SP]

Anybody using a sharp GP1U58Y? Is this a good choice for the recieving module? I'm interested in building a UIRT based on Mr. Ruud Van Gessel's design and I'm wondering if this part will work as it's the one I have readily available. I ordered a couple from B.G. Micro a while back when they had them. They have the datasheet here on their site.

http://www.bgmicro.com/pdf/gp1u58y.pdf

Should I be okay with this one? If not where can I purchase a more suitable module?

[kari]

Going by a cursory glance at the datasheet, it seems probable that it'll work. Well worth trying at least, if you actually have the device handy. Beware the pinout though, I notice that it has Vcc and GND reversed in comparison to the SFH5110. Actually, that goes for any receiver you would care to try, there seems to be no standard pinout.

As an aside, I can report that I have replaced my SFH5110(36kHz) with a TSOP1738, with excellent results. I haven't actually done any specific testing for receiving distance, but when using the remote at 3-4m distance I do not have to point it directly at the receiver any more. The receptiveness now seems to be at least on par with the best you get with OEM equipment (short of RF remotes, that is).

-Kári.

[Holger]

So,

I will tell you the way I will do it:
I buy a TSOP1738 (because 38 kHz is a very common frequence and the most remotes are in the range of 36 - 40 kHz) and to generate my own codes for the philips pronto. For everybody how doesn't have a Pronto: With this way your receiver is optimized for Pioneer or Kenwood remotes...

Best regards
Holger