Hi there!

Does anyone know what manufacturer the irda IR transceiver module on this one is? I'm planning on using the 3630 as a universal remote and need better ir range. Either I will see if there are some replacement modules or if it is possible to increase the range on the one used. The second option I have is to add one or two IR diodes and see how that turns out. There is actually some space in front of the existing irda module so it might be possible to add one or two small surface mound IR diodes there or I might drill a hole in the front for a 3mm IR LED.

Yes, I do know about the plugin modules, but I do not want those...

Anyone looked at this before?

Perhaps you should read the IRda specs before destroying your iPAQ.

IRda, by design, has very limited range. It uses no carrier, puts out little power, has a narrow angle, and uses a different wavelength than Consumer IR.

sorry, this is only available in German, but perhaps the information you can get from this is enough for you

[Link: svenketel.de]

Wilhelm

Thank you for the link. It was just what I was thinking of and looking for. I read some German so that is ok.

Dave: I wasn't going to destroy the ipaq - enhance it... Even though the irda states requirements there are indeed differences between different transceivers. I guess 880nm is a typical wavelength and around 940nm is used on most remotes. But a typical receiver might still have about 60-70% sensitivity at 880nm if it has a peak sensitivity at 940nm. Adding a proper diode is however the best thing anyway.

I've bought some nice 1206 diodes (and a few others to test). I'll try to make a tiny 0.5mm thick circuit board and mount the diodes in the middle of the IrDA transceiver and see how it works out.

While it may not destroy your iPAQ, it will certainly void your warranty.

So Tomle:
I suppose these diodes are SMD? If your done testing, could you please report your results?
I am currently using a TSAL6200 which is brilliant, but it's only available with a 5mm caseing, so I mounted it in the headphone hole but I am anxious to hear about your results. Perhaps the headphone could go back in.

Wilhelm

Hi there!

Just finished my initial testing and I must say that I am very pleased. I'm not able to make a printed circuit board until a week or so so I just mounted the diodes on a small pcb test strip and mounted it in front of the 3630. And it exceeds my expectiations. In a 4x3m room with a ceiling mounted projector I could stand anywhere in the room and point the ipaq in any direction and it worked... Havent been able to test direct distance because I have no room big enough, but with one reflection I tested it to about 8-9m.

What I did is to mount two 1206 (1.5mm x 3mm smd) diodes close together and tilted them slightly away from each other, about 20-30 degrees to get a better horizontal spread. I connected them in series activated by a small SOT-23 footprint transistor. I did not use a series resistor as I don't have space and there's actually no need. As the current increases through the diodes the forward voltage increases and also the transistor has some internal resistance. So I ended up with about 60mA flowing through the diodes in this configuration.

When I make the pcb I will mount the transistor on the rear and thus I will only have three wires down to the main pcb and that's it. The pcb will be about 3mm x 4.5mm, just a perfect fit in front of the IrDA module. I don't think the performance should be much different when mounted inside because it will be placed directly underneath the IR glass plate.

The diodes I used are spec'd 940nm, 100mA, +/-30 deg.

I'll get back with more info when I have made the pcb.

Sounds good, could you give me the exact type of the diodes, manufacturer and perhaps a distributer.
I'd recommend a 2SD1664 transistor. It could give you even more power. It has a satuarion voltage of as little as 0.1V which helps a lot if you only have 3.3V supply.

Thanks

Wilhelm

Where did you find the diodes? I've been unable to locate SMD emitters at 940nm.

Seems that all the account information has been lost on this messageboard so I had to register again... but anyway:

The diodes I used are ELIR11-21C from Everlight (www.everlight.com). Be aware that there are diodes with the same name only with an added ending which are 850nm. Everlight also has several other smd diodes at 940nm. I bought mine from Elfa, a Scandinavian/Nordic catalogue distributor, but Everlight has distributors everywhere. I'm sure there must be other manufacturers out there also with ~940nm smd diodes.

I have been thinking of getting another transistor with lower Rds but I used what I had for testing. That I will figure out when I have made the pcb. I see for instance Vishay has some very low Rds (<0.5 Ohm) SOT-23 ones and also in smaller packages, but SOT-23 is ok. If you want to really maximize power you should use low Rds mosfets since bipolar transistors will give you about 0.2V drop at saturation and they might also need too much base current from the TX signal. For the test I used a Philips PMBF170 which will saturate at about 60-70mA at 3V Vgs. One should be careful though not to draw too much current also.

Hmmm.. according to the datasheet for the IR diode it will at a forward voltage of about 1.65V (3.3V/2) draw nominally about 200mA which might be too much, so a too low Rds mosfet is not recommendable either.

Hello!

Just wanted to sum up my experiences with mounting new IR diodes in my IPAQ. I have finally taken the time to do it properly(?) and I put some pictures onto my web page to describe what I did:

[Link: home.c2i.net]

The IR range and angle is very good and on par or better than my ordinary remotes. Some of the IR receivers are actually a limitation due to stupid mounting on the devices...

Hi Tomle,

Congratulations!
Thank you for taking the time to enlighten us with your website.
I'm no electronics genius but would like to do the same on my 3850. Could you add an idoits guide (with disclaimer of course ;) ) for those of us contemplating the same.
A nice lurvely thin iPaq would be so much better than thick beast/CF jacket/CF card.

Kay.

Your website has some very interesting data. However I have a slightly different problem, since my Windows CE device is an H/PC Pro nobody seems to have thought of writing a universal remote program that works with it over IrDA.

But that doesn't matter so much - I have a One-For-All 6 which works with my NTL Pace DITV2000 set-top-box [IrDA only]. However the IrDA range of the OFA6 is very limited compared to the NTL-supplied remote - or with its own range when sending RC5 - and worse still when used with my lovely new AEI IrDASender remote extender. So I wondered whether you could advise me of how to make similar enhancement to the OFA6... ideally without wrecking its other [RC5] capabilities?!

Thanks VERY much, I'm quite handy with a soldering iron and I have a Maplin electronic store nearby - but my knowledge about circuit design is now 20 years out of date...

[email protected]

Hi!

Regarding "idiots guide"... I currently don't have time to do more updates right now because if this would be done as a simple step by step recipe it would take me a few hours. However if you have a concrete question feel free to ask. I'll see what I can do later if anyone has any interest of it.

Re. OFA6. I don't know about that one. It might be a bit harder to get better IrDA performance. If you're lucky it might be possible to exchange the current IrDA module with a new one that performes better. If the transmission range is the problem maybe it would perform better if you increase the transmitter current. Most (all?) IrDA modules have an external current limiting resistor that can be changed. Maybe - I don't know the device or the IrDA module it uses.

Hi,

just wanted to ask you one question. Does this affect the normal IrDA capabilities, or does it seem to work the same?