Hi all,

I am a new to this area.
I want to build a universal remote control based on microcontroller. It is intended to controll only VCRs.
Does anybody know where I can find the various remote controll protocols ?

Thanks,
Jan Den Besten

I am not sure this is the right forum for this question.
Is it ?

The best source I know is one I wrote myself:
[Link: john.fine.home.comcast.net]

That page was written as documentation for DecodeIr.dll, not as documentation for IR protocols, but it has an IRP notation specification for most of the protocols DecodeIr.dll can decode.

IRP notation is a precise, concise system for specifying an IR protocol. It is described in various posts, primarily in the JP1 group, though if you know the structure of a few IR protocols and then look at the IRP notation for those the general rules should be obvious.

The easiest way to make a generator for many different protocols (such as a universal remote) would be to make a program that understands IRP notation and uses it as the guide to generating the signals.

My MakeHex program (source code available at [Link: john.fine.home.comcast.net] ) generates Pronto Hex from an older form of IRP notation. It is a good C++ example of how to translate from an IRP notation to the actual signal. If you don't like C++, a couple other people have written Java code to translate from IRP notations, but I don't have URLs handy at the moment.

If you don't yet understand the basics of IR signals, this site: [Link: xs4all.nl] gives very beginner friendly explanations of several of the more common protocols. It is a great introduction, but I wouldn't use it as the basis for coding a universal remote because it treats a moderate subset of the ways data is encoded into IR as if that were more representative of the full range than it really is. If you use that as a guide rather than an introduction you would design in a way that is hard to extend to a broader set of examples.

Lots of IR on the web is presented in Pronto Hex. If you want to make good use of that information, you should read Barry Gordan's document at [Link: remotecentral.com] but there it is even more important to treat the discussion of IR theory as introduction and important examples, not as the basis for a design.

The limit to VCRs doesn't significantly reduce the range of possible protocols. A large majority of IR protocols that have been used for anything have been used for VCRs. A restriction to USA VCRs or a restriction to European VCRs would have a much bigger impact on reducing the scope of the problem. A lot of IR protocols have been used in VCRs sold in Europe, but never in VCRs sold in the USA. A smaller but still significant number have been used in the USA but not in Europe.

Hi Johnsfine,

Thank you for the detailed explanation.
And after I know the different protocols do you know where I can get the actual keys codes e.g. Toshiba, JVC, Sony etc. VCRs - Power Key code, Play code, Stop code etc.

Thanks
Jan den Besten

For Sony the best source is: [Link: hifi-remote.com]

For a wide spectrum of brands, there are several online libraries of IR information.

If you are using something like an IRP notation to convert from Protocol:device:command to IR signals, then it may be easiest to use a library of data already in a Protocol:device:command form, such as the library of JP1 upgrades for VCRs at: [Link: hifi-remote.com] Some of those files are designed to be read with the JP1 Java program RemoteMaster. Others are designed to be read with the JP1 Excel spreadsheet KeyMapMaster (but RemoteMaster is also able to read almost all the KeyMapMaster files).

I think the most extensive online library is on the same website with this forum, at [Link: remotecentral.com] It is sorted by manufacturer before type, which makes it a little less convenient to look for all VCRs, and most of the files are full system configurations, making it lot less convenient to extract VCR info. But it can be a very useful resource. My program DecodeCCF is the best way to extract IR data from those CCF into a form that could be incorporated into a new universal remote.

There is also a useful IR library at [Link: lirc.sourceforge.net] but I don't know any software that would make it practical to translate large quantities of that data into a more useful form. Similarly the library at [Link: ir.premisesystems.com] has lots of obscure models you may not find elsewhere, but all in a form that is tedious to convert to useful (one command at a time using the JP1 version of IrTool.exe and DecodeIr.dll).

Toshiba, JVC, and Sony are all easy because they have so little variety across models and are so common. You could find all the data you need in any one of the above libraries of IR signals, looking at only a few files.

But other brands won't be as easy.

BTW, Toshiba uses the NEC1 protocol, which is also used by most of the very minor brands sold in the USA and by a few other large brands. JVC uses primarily their own protocol, which is almost never used by other brands. Sony uses almost exclusively their own protocol, which very very rarely used by any other brands (my guess is that the other brands using Sony protocol are all unauthorized copies sold only in Asia).

In Europe most of the minor brands use one of the Philips protocols (I think they do so under license from Philips).

Thanks again,

Jan den Besten