Convert IR to Serial

[hank]

Hello - I want my slingbox remote to control my video switcher, which is currently controled through dial-up with an external modem connected with a serial cable.

Is there something out there that will take the IR signal and convert it to a serial connection? Everything I see seems to require a PC. The device I'm controling uses basic hyperterminal commands like "switch 2" and "switch 2"

Thanks

[johnsfine]

What baud rate does the switcher need?

You could buy a simple inexpensive IR sensor component. That needs only a source of DC power in order to convert an IR signal to a wired signal.

Baud rate is important because modulated signals are much more reliable and have higher range than unmodulated, but the modulation rate must be much higher than the baud rate. But IR sensors with very high modulation rate cost more normal modulation rates. Unmodulated might work well enough, because with a slingbox you could set up the physical relationship between the IR emitter and IR sensor however you want and probably find the relationship that works well.

An executor could be written for a typical JP1 remote to send out the timing and structure of a serial signal. A slingbox uses very similar executors but with some size limits. A slingbox also lacks macros, so all the work must be done in the executor (in a regular remote you might decide to do some of it in macros).

I'm not sure how much you would have room for. At best I think you would be limited to a very small set of commands.

I think Rob knows a lot more than I do about the limits on executors in a slingbox.

[The Robman]

I think Rob knows a lot more than I do about the limits on executors in a slingbox.

The only limit is size, other than that you can do everything that you could otherwise do in a remote. I don't recall the exact size limit, but the size is for the upgrade and the executor combined, so if you don't need too many buttons, you can have a larger executor.

[bvwelch]

Greetings,

If we could specify that you always use, say NEC1 codes, this sounds like an easy project to build with a picmicro. For example, the 16F88.

We could use the serial port to configure the unit, and then save the parameters in the built-in "eeprom" memory of the picmicro.

I could do it, time permitting, if there was some interest.

William

[johnsfine]

I want to explain the difference between what I suggested earlier and what William just suggested.

If you use a micro in the IR to serial conversion hardware, then everything you need to do on the Slingbox side becomes trivial. There are no special worries about that size limit or the baud rate. There is no reason to use a high modulation speed IR sensor nor an unmodulated one, just an ordinary modulated IR sensor.

But if you use a micro, rather than just an IR sensor in that hardware, then building and programming that hardware becomes harder. Connecting a single low cost component to power at to the device that needs the serial signal is pretty easy. Even I could do it. Connecting a micro first to a PC for programming and then to the IR sensor and final device for use is quite a bit more work.

[bvwelch]

Greetings,

Yes, both approaches are very interesting projects.

Just to expand on the 16F88-- I could supply free schematics and source code, or I could provide pre-programmed chips, or I could provide some sort of "kit".

As an example, you could purchase a pre-assembled board like this one for under $20 US, and add a cheap IR sensor ( just power, gnd and signal lead).

http://www.olimex.com/dev/pic-p18.html

In operation, it could be configured using any PC with hyperterm. You would be able to assign ascii strings to different NEC1 commands. These settings would be retained in the picmicro's eeprom.

For those who like to do their own firmware, I could make the source code freely available. I use a free C compiler.

Also, since the 16F88 has a free "bootloader", we could upgrade the firmware, using the same serial port, and free "bootloader" software.

If we wanted to also use something like this for working on the direct implementation of IRP notation, we might choose a slightly fancier picmicro, which has more code space. But still has the same bootloader concept, and a free C compiler.

William

[classicsat]

You could "hard" connect the IR blaster form the slingbox to the micro pretty reivially. Yuo just neen an L-C filter to filter out the 38-40Khz IR pulses, leaving the data stream.

[bvwelch]

Greetings,

I just finished a new revision to a related project, which uses basically the same hardware. You can read more about it, and find a link to the schematic and software here:

http://www.hifi-remote.com/forums/viewtopic.php?t=5380

William