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Superpilot
16th Aug 2005, 11:39
Hello all,

Hope this makes sense. I am working on another one of my lovely projects and am looking for a device that one can plug a headset phono cable into and then plug the device in question directly into the phono jack on an aircraft, the device has two or more inputs, thus allowing two audio sources to be played through the headset.

An example of it's use would be to plug in an mp3 stereo (now I'm not going to give away my plans am I?) into a port on the device so that the music aswell as the aircraft radio can be heard through the headset. What would be even better is the ability to make one audio source have a greater priority than the other, for obvious reasons!

The device does not have to be made specifically for aviation. I know there are some expensive portable intercom solutions out there but I think they are overkill for my task.

Anyone? Thanks muchly

1946
17th Aug 2005, 03:20
Simple home made device, Headphone socket (line type-not pannel) wired to standard phone plug, ie an extension cord device- wire a stereo /mono phono plug, to suite your secondary device, direct into the back of the socket plug. The whole lot can be obtained from an electronic parts store. Made up can be used any where-any time, and no mods to the aircraft pannel.

tmmorris
17th Aug 2005, 05:33
Unfortunately for your plan, while an audio signal can be split easily enough using a Y-cable, you can't combine two audio circuits like that: you need a proper mixer circuit. Sure, you could build one, but it would need some electronic knowledge: it's not just a case of getting the right sockets and wiring them up.

You might therefore find your only option is to buy a ready-made device. You are more likely to find something simple in one of the American catalogues - they like to listen to music as they go. Try www.sportys.com.

That said, I don't think it's a good idea. Perhaps as a professional musician I find music more distracting than most, but I don't think I could manage another distraction in the UK's busy airspace (remember an American pilot can go for a long time without needing to hear a radio call, unlike here).

Tim

IO540
17th Aug 2005, 06:18
One can achieve audio signal mixing with a miniature transformer and no other components.

The commercial intercoms thathave "crew music" input implement a mute function so when ATC speaks the music is muted, which seems pretty well essential (for the pilot).

Three Blades
17th Aug 2005, 08:35
I agree with tmmorris, you cannot 'add' two supplies together without a simple mixer without cross loading the supplies.
However you can build a simple mixer or combiner. This web site has some good simple solutions:

http://www.epanorama.net/circuits/linesum.html

One alternative solution would be to use a space mic socket to feed the audio into your aircraft's intercom system. The thing you have to bear in mind here is that the audio supply will be much higher level than the mic input can stand and hence it needs to be attenuated. Sounds complex ? Not really, the same site has another solution:

http://www.epanorama.net/circuits/line_to_mic.html

You probably need to use the version for electret microphones and also use the combiner sircuit to combine the left and right output from the audio.

Failing all this, go to

http://www.transair.co.uk/Category.asp?ID=1&Category_ID=617

and use their telephone adaptor to play your audio through.

nigelisom
17th Aug 2005, 13:57
Or just buy a Lightspeed headset which has it all built in (including auto muting of the music source) and comes with the necessary cables to conect your player or mobile phone if you wish.

Nigel

Flik Roll
17th Aug 2005, 16:41
You can do it...someone i know has one - useful for recording radio calls/intercom when making vids as well :ok:

rugmuncher
18th Aug 2005, 16:46
Use on of these things, plug it in to your component and listen in on radio, whilst also listening out on other frequencies.


http://www.bestbuy.com/site/olspage.jsp?skuId=5755426&type=product&productCategoryId=pcmcat33100050012&id=1056899518024

Or use an i-Pod i-Trip,

Not exactly legal in the UK due to transmission laws, but hey, we aint talking about doing anything legal any way are we?????

Three Blades
19th Aug 2005, 07:47
Rugmuncher :ooh: ,
Have you used the iTrip or similar in an a/c ?
I wondered if the frequencies match with a/c radio or NDB frequencies.

rugmuncher
19th Aug 2005, 15:38
i-Trip for an apple i-pod works from the following spec:

Compatible with all iPod models, including 4th generation models

Digitally select from more than 100 stations; choose any FM station on your dial between 87.7 and 107.9

Digital tuning eliminates signal drifting

10' to 30' operating range (depending on quality of FM radio receiver); built-in antenna

Shuts off automatically after 60 seconds of silence

Battery-free operation powers directly from your iPod for minimal energy consumption

International frequencies software selectable

http://www.bestbuy.com/site/olspage.jsp?skuId=6966152&type=product&productCategoryId=pcmcat33100050012&id=1099385767261

It would be wrong for me to say where this has been used, but suffice to say it does work well :ok: :mad:

Squawk7777
20th Aug 2005, 01:02
Is this (http://www.marvgolden.com/headsets/pilot86aadapter.htm) what you might be looking for?

7 7 7 7

S-Works
22nd Aug 2005, 11:45
Or you could fit a GMA 340....

I listen to my iPod on long flights where I have minimal radio work.