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Ipaq 3850 - IR to RF then RF to IR - Working!
This thread has 7 replies. Displaying all posts.
Post 1 made on Saturday September 23, 2006 at 04:41
robcornwall2003
Long Time Member
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January 2006
10
Hi all, ive just this minute tried out my new electronic circuit on my PDA to achieve a wireless all in one remote that works across the house (even through walls).

Basically ive managed to squeeze the IR to RF convertor and RF transmitter into an Ipaq 3850 (had to put in the SD card area, but i dont need that slot) then built an RF receiver which then converts the RF to IR and beams it back to the set that ive got.

Its kinda like one of those kits you can get from the stores but the beauty is that the transmitter circuit is inside the PDA and always facing the IR transceiver of the PDA so no matter where you go (providing your in range) and where you point the device it works!
Post 2 made on Friday October 13, 2006 at 04:25
danglerb
Long Time Member
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May 2006
11
So how do you like it after a few weeks?

How does it effect battery life?

Was it essential to put it inside, or could you do the same thing with a "blank" SD card making the connections?
Post 3 made on Friday October 13, 2006 at 14:51
Mr Twister
Long Time Member
Joined:
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September 2004
100
On September 23, 2006 at 04:41, robcornwall2003 said...
Hi all, ive just this minute tried out my new electronic
circuit on my PDA to achieve a wireless all in one remote
that works across the house (even through walls).

Basically ive managed to squeeze the IR to RF convertor
and RF transmitter into an Ipaq 3850 (had to put in the
SD card area, but i dont need that slot) then built an
RF receiver which then converts the RF to IR and beams
it back to the set that ive got.

Its kinda like one of those kits you can get from the
stores but the beauty is that the transmitter circuit
is inside the PDA and always facing the IR transceiver
of the PDA so no matter where you go (providing your in
range) and where you point the device it works!

Wow. Who is the manufacturer of your tranciever? Could you please let me know all the process in detail? I look forward to your response!
OP | Post 4 made on Friday October 20, 2006 at 03:15
robcornwall2003
Long Time Member
Joined:
Posts:
January 2006
10
Thanks for the responses.

This is an email i sent to someone who asked about the unit.

-----------------------------------------------

Ok this aint the easiest project ive ever done but you need to get the transmitter and receiver kit from here

[Link: rentron.com]

the transmitter circuit can be modified to be simply than what the diagram shows at the URL above. Basically you need the IR Reciever (its the TSOP-1140), the 2.2k resistor from the OUT of the IR Reciever needs to be 1.2k (at the most, in fact thats what im using but i think ill need to drop the value to 800R or 1k) to the base of the transistor, and the actual transmitter circuit with antenna. NOW the TSOP-1140 is a 5v IR reciever that you get with the kit and is no good because most PDAs run on 3.3v, i swapped this component for the TSOP-34838 (you can use the TSOP-34840) which will work at 3.3v.

Now thats the transmitter part, i put this into the SD Card slot of my PDA (it just fitted and theres plent of room above the SD slot and even then its pretty tight so i dont know if it'll work on all PDAs). The IR Reciever, thats the TSOP-34838 needs to go either in front of you IR port on the PDA OR (like i did) but a bit of tin foil over the IR port (inside the PDA) and sat the IR Reciever behind it and glued it in position (this is internally of the PDA). So when the PDA transmits out of the IR port, it reflexs and back into the IR Reciever of the transmitter.

The actual RF to IR Receiver of this project (as shown in the URL) ive left as it is and works fine. There is however a problem. The Transmitter of the circuit (in your PDA) needs the antenna outside of the PDA as its shielded and no RF signal gets through it. Also when the RF - IR circuit recieves a signal it is depentant on the signal strength to how well it works so the closer the transmitter (PDA that is) the better it actually works. Now im working on the RF - IR receiver to be better with a buffer before it actually sends the IR signal to the cinema unit sets so the signal strength is always very strong but yet to do that.

If you would like (it'll take me a few days to do) i can do a circuit diagram of what ive used from the URL and couple pictures of the setup (including inside my PDA where the circuit is).
OP | Post 5 made on Friday October 20, 2006 at 04:07
robcornwall2003
Long Time Member
Joined:
Posts:
January 2006
10
sorry i didnt answer the first response.

The unit over the last few weeks has performed great, i upgraded the battery to a 2250mah (original is about 1400 i think) and the controller seems to last over 2 - 3 days before warning the battery is low (about 3 hours of constant use, so by commiting to this circuit inside your PDA it mean treat your PDA as a TV remote, very little use). Unfortunately the circuit does run all the time, not sure when the PDA is sleeping (havent tested the drain across the circuit in that state). However, i plan to build a charging station on the wall so i can simply drop the PDA into it over night to charge. If you were to do this project then i strongly recommend upgraded the standard battery in a PDA to the best you can get. Look on ebay, cheapest and without a doubt the most mah you can get.

Ive found about 90% of the time the PDA with this circuit working well. The problem is the actual receiver (RF to IR) with two IR facing the cinema set. Although the distance is good (about 5m) the angle isnt of these IR LEDs so im either gonna redo the receiver and install 6 IR LEDS at slight angles or buy 2 wide angle LEDs as distance isnt the issue for me.

Using an SD card type size of this circuit isnt possible due to the transmitter chip being standard size. The hardest part of this project was actually fitting it into the PDA. The 3850 has tonnes of room inside around the SD card (especially in height which is what you need for the chip).

My wife to be very soon, has commented on the PDA as good thing to replace our 5 controllers but it needs a little tweaking to get it response each time you press the button (thats the 10% sometimes it doesnt respond and due to the IR transmitter not having enough angle or IR LEDs.)

One thing i did forget to mention when installing inside the PDA, the IR Reciever that sits behind the IR port of the PDA and using tin foil to reflect the IR signal back into it needs to fit over only the IR Transmitter of the PDA NOT the IR Receiver of the PDA. Usually the IR of the PDA is a transceiver, i.e. it'll be 1 component with two IR LEDs, one to transmit the other to receive. If your not sure which is which, then get a digital camera, view through the LCD of the camera the IR transceiver of the PDA (of course the PDA casing will have to be removed for this) and transmit a TV command, you then should see which of the IR is transmitting. IF you cover both IRs of the transceiver then you wont be able to learn IR commands from the remotes because its blocked!
Post 6 made on Saturday November 18, 2006 at 20:08
worldwins
Lurking Member
Joined:
Posts:
November 2006
1
Sounds like a project I want to try, as well as building a remote video camera control using a Sharp remote Rx have for a dead Sharp videoCam.. I've got a couple of iPAQs lying around, ready to hack, but one of them has a blown battery regulator (I used too high a voltage AC adapter).

Any ideas where I could get a circuit diagram for the 3650 or 36xx? Or hints on what type of regulator chip is used? Is this too off-topic?
OP | Post 7 made on Wednesday March 7, 2007 at 08:09
robcornwall2003
Long Time Member
Joined:
Posts:
January 2006
10
Hi guys, well its been 6 - 7 months since building the IR to RF project in the Ipaq and sadly the Ipaq touch screen has failed leaving it completely useless. Looked into replacing the touch screen digitizer but at 35 i might as well replace it with a second hand Ipaq off ebay.

Therefore im hunting for a HP 3970, its cheap, doesnt have the awful side light for the LCD (better clarity), faster CPU and hopefully more room inside for the IR to RF circuit to fit as opposed to taking up the SD slot.

The great thing about this product is it comes with Nevo remote as well.

If i dont have the room instead then i might approach the IR to RF circuit slightly different...not sure yet...but ill mod an SD memory card to hold a tiny external case that will hold the IR receiver and RF transmitter so it can be removed easily.

Also the RF to IR part ill be upgrading to have at least 10 IR LEDs for transmission to the cinema unit (transistor is capable of handling 1 amp so plenty of power)

Lastly ive been using PDAWin's TV Controller 5.7 software in this setup and its fantastic as it allows hardware buttons to be used as well as the screen unlike Total remote.

Please feel free to contact me if you want more details, one day i plan to make a how-to guide for all of this but depends if i get the chance :)

Cheers
Post 8 made on Thursday May 3, 2007 at 18:12
tonyn41
Long Time Member
Joined:
Posts:
April 2007
27
Interesting project!
I wonder if using a 418mhz IR-RF module that you could then use URC's MRF250/MRF300/MRF350 RF-IR extenders?
I presently own a URC mx-950, which has both IR and RF transmitters in the remote.
I know that it transmits at 418mhz to URCs MRF RF-IR extenders.
But I don't own a RF-IR entender, but I am going to be hiding some of my components shortly, so I'll need RF.

I also am interested in using these PDAs as remotes(I just ordered a HP rx3715).
But I want to use RF on them instead of the IR or WiFi for compnent control, and also be able to use the mx-950, using RF, with one RF-IR entender unit for both remotes.


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