Tablets as a universal remote ?
 

Dedicated remotes should be thing of the past. I agree with the below article although it's aimed at the iTouch/iPhone.

http://www.pcmag.com/article2/0,2817...079TX1K0000585

But how far are we from replacing the universal remote with our tablets? For controlling network enabled devices, it's possible, Sonata, Maestro Mini and others.

What's missing for the tablets to replace all current remotes are two things, a reasonably priced IR blaster than can be controlled via the network and of course the remote application and remote code database for the tablets.

Last I looked for a network controlled IR blaster, it was between 100 and 200 dollars. Anybody know of something under $100?

Remote codes are widely available http://www.remotecentral.com/cgi-bin...nto&db=devices so that's a matter of translating an existing format into something the tablet understands.

Some universal remotes sell for a price similar to the tablets. http://www.amazon.com/Logitech-Harmo...5469936&sr=8-9

Am I missing any pieces to make this a reality? A universal remote that also happens to browse the web, check your email and chat?

Frank

Re: Tablets as a universal remote ?
 

We've already got Irreco for the tablets: http://www.internettablettalk.com/fo...ad.php?t=15919

All we need is a IR transceiver. (the referenced thread mentions some usb-based ones for $40 a piece)

I think that this could work quite easily. :)

Also, if you were interested in a more complicated hack, there's three different LEDs in the upper left corner on the N810 at least (I don't know about the N800). Unless you absolutely need Red, Green, AND Blue notification LEDs then you could replace one of them with an infared LED and replace the plastic "window" over the LEDs with some infared-transparent material :) I don't actually know anything about the feasibility of this as I have no idea how finely the LEDs can be controlled. (I believe they're accessible by DBUS commands)

Re: Tablets as a universal remote ?
 

A built in IR transmitter is probably the better answer. The N900 needs an IR transmitter built in. But that probably doesn't fit with it's "theme" very well.

Thanks for the pointer, it didn't offer a reasonably priced solution but did give me some more things to think about.

Frank

Re: Tablets as a universal remote ?
 

I wonder if you couldn't work something up that used the audio jack?

Say you made a hardware 38kHz modulator, and then just turn it on/off from the phone jack -- play the right wav files and you're good to go.

IR LED's don't use all that much juice. (Worst case is it'd require a small battery.)

Hmmm... if it weren't Halloween weekend, this would be a fun project...

Re: Tablets as a universal remote ?
 

I'm thinking two IR LEDs back-to-back (i.e. parallel, but reversed) across the right and left channels, with a current-limiting resistor, would suffice. Output a 19kHz tone, and you'll get 38kHz light (each lights on opposite half-cycles), so it would be just a matter of composing a .wav file, setting up the sound, and playing it.

I did a little testing here:

• Using an ALSA mixer from Debian, I'm able to get up to 2V p-p per channel; driving the channels out of phase gives 4V p-p, which should be plenty.
• With no ALSA mixer, just kicking the volume to max, I can get 2.5V p-p (both channels).
• Attenuation with both channels into a 110 Ohm load is about 20% (2V p-p), so it looks like the Thevenin impedance is about 25 Ohms for this configuration.

Allowing 1.3V across the diode, 1.2V into 25 Ohms gives about 50 mA, so no resistor should be needed. (Something like 100 mA if you do kick it up to 4V, but @~25% duty cycle, still no resistor needed if the LEDs are rated for at least 50 mA continuous.)

So just two IR LEDs and an 1/8" jack should do it, I think.

Re: Tablets as a universal remote ?
 

Re: Tablets as a universal remote ?
 

That article makes for very interesting reading, as does this page regarding reading IR via the audio ports using LIRC http://www.lirc.org/ir-audio.html

Digging though my bits bin from my mythtv setup, I have a IR receiver spare from a hauppauge card and a transmitter module from a MCE remote module.

Think I might have a go at recording IR, and then seeing if I can transmit it by playing it back.

This will possibly need lirc porting and building for maemo - anybody up for it?

Re: Tablets as a universal remote ?
 

I could be wrong, as no technical details are given, but I'd guess that the Griffin unit discussed in engadget contains an integrated photodiode/detector circuit to give constant output when the carrier is present, and has a 38 kHz modulator for the output.

They said they're sampling at 44.1 kHz, and while I'd initially considered sampling a 38 kHz signal at 44.1 and using a narrow bandpass to recover the 38 kHz harmonic, it looks like a signal amp would be required to make that work well.

So if I had a recording from a PD/detector (arbitrary sampling rate, stereo) and wanted to convert it to playback on a dual-LED circuit as discussed above, something like This ignores the right channel of the input, but still requires stereo input. I couldn't figure out why, but sox doesn't like it with mono....