Fallingwater | # 771 | 2012-10-20, 13:35 | Report

I figured out the problem.

It's not a problem of range; rather, at least on my N900 it's a problem of direction. It seems my device's IR LED is very directional and I have to point it exactly at the TV's receiver. At couch distance if I point it at the right side of the TV it doesn't even register, but it works if I point it at the left lower side.

I'm thinking of cracking open my N900 yet again and swapping out the LED for something a bit more useful.

Copernicus | # 772 | 2012-10-20, 13:57 | Report

Wow, that's a very tight beam indeed. Let me check mine...

Well, that's interesting! Just eyeballing it, my main N900 (a revision 2204 device) can be pointed maybe 30 degrees left or right of the target and still activate it. Up and down is better, maybe 45 degrees off. My testing N900 (revision 2101) does better though, roughly 45 degrees left and right, and 60 degrees up and down.

So it does seem to vary by device. I'm not sure whether that'd be a function of the IR LED itself, or perhaps how deeply it's been set into the case...

Estel | # 773 | 2012-10-20, 14:40 | Report

Then you will run into problem of too low amount of power, to drive more omni-directional diode - it may work, but for a change, you will end up with beam of ~70 degrees coverage, but requiring to be 20 centimeters from receiver

I have tried that myself, once (also putting diffusing lens from old remote, in front of N900's one), and it just won't work. Only one feasible way is to build small IR blaster/repeater, which gets commands from N900's IR transmitter, and repeats them using powerful beam. (this way, you build powerful IR cheaply, that can still make use of awesome programs like Pierogi).

/Estel

Cue | # 774 | 2012-10-20, 19:03 | Report

what is the highest frequency for pierogi?
Maybe replacing the LED with an optocoupler and wiring an IR LED on the back cover connected directly to the battery is an alternative. Would high frequency signals get destroyed?

Estel | # 775 | 2012-10-20, 19:18 | Report

AFAIK N900's IR diode's (+) voltage is connected with battery - the problem is with element after (-) side of diode (can't remember name now), which got pretty low limit of current passing.

mini Ir repeater, wired inside N900 with bigger cover (aka mugen one), could make it possible to put everything inside device. Still, it would require pretty nifty miniaturization, and would rather require single battery (no dual-scud + ir repeater inside, sadly, unless you can prepare it from really micro components, and solder under microscope).

/Estel

sixwheeledbeast | # 776 | 2012-10-20, 19:35 | Report

This is worth a read

Also don't forget

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Last edited by sixwheeledbeast; 2012-10-20 at 19:43.

Copernicus | # 777 | 2012-10-20, 19:39 | Report

I think the easier solution would be to do what iPhone & Android folks are doing, create an IR dongle of some sort, and send the commands from the phone to the dongle (via wifi or bluetooth or whatever). I don't know how much work this would take, but there seem to be plenty of folks selling products of that sort...

Estel | # 778 | 2012-10-20, 19:41 | Report

But that require dedicated hardware, able to receive commands over bluetooth/wifi. IR repeater can be build very cheaply, if not free (when using components scavenged from old devices/other projects).

not to mention, that our IR transmitter isn't becoming totally obsolete, as with sending commands over bluetooth/wifi

/Estel

// Edit

From sixwheeledbeast's link - this post seem to be conclusion:
http://talk.maemo.org/showpost.php?p...7&postcount=21

Although, I don't know, what it mean in practice, it's not my area of expertise (yet). Does he mean, that we can just replace resistor by ones with 1/2 or 1/4 resistance and it will work with higher current (not voltage) flowing through diodes (= more power, or possibility to insert better diode), or not?

sixwheeledbeast, what you understand from that post?

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Last edited by Estel; 2012-10-20 at 19:51.

Cue | # 779 | 2012-10-20, 21:17 | Report

with an optocoupler in place of the diode it would not matter, would it? The two circuits would be isolated. You could even go for a Darlington pair optocoupler just for good measure. The new IR diode could run off 3.7 volts directly from the battery instead of being limited to 1.8V or the component limited current on the other side of the opto. It's also just three components (or two if you buy an LED with a built in resistor); an optocoupler, an LED and a resistor. I'm not brave enough to give it a shot (I only have one n900). It is just an idea for anybody wanting a more powerful IR diode built into their N900. The optocoupler/LED/Resistor combo is in a sense a repeater and can be made very small ( easy to fit into mugen type cover).

P.S. would an IR Emitting Diode be called an IED instead of an LED? Not the explosive type obviously.

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Last edited by Cue; 2012-10-20 at 21:29.

sixwheeledbeast | # 780 | 2012-10-20, 21:34 | Report

IR LED, IED is normally used for Intelligent Electronic Device.

There still emitting light no reason to drop the L.

The issue is if the transistors can handle the current.

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Last edited by sixwheeledbeast; 2012-10-20 at 21:59.