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#1
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video-cam adaptor
is there an adaptor that'll take the head-set
audio-out of an airplane intercom into a jack that can be put into a standard microphone jack in a video-cam. |
#2
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I don't know of an off-the-shelf adapter, but it needs to be an
impedance adapter. Headsets are typically 150-300 Ohm, with voltages running upwards of 10V. Portable devices like cd players and other line-in critters use a much lower voltage, and expect a lower source impedance. If you truly want to go into the mic port, it'd have to accept and modulate the bias voltage coming from the video-cam as well, I'd expect. If it were me, I'd build one... but need to do more research first. -Cory Bonanza Man wrote: : is there an adaptor that'll take the head-set : audio-out of an airplane intercom into : a jack that can be put into a standard : microphone jack in a video-cam. -- ************************************************** *********************** * The prime directive of Linux: * * - learn what you don't know, * * - teach what you do. * * (Just my 20 USm$) * ************************************************** *********************** |
#3
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#4
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Newps wrote:
wrote: I don't know of an off-the-shelf adapter, but it needs to be an impedance adapter. Headsets are typically 150-300 Ohm, with voltages running upwards of 10V. Portable devices like cd players and other line-in critters use a much lower voltage, and expect a lower source impedance. If you truly want to go into the mic port, it'd have to accept and modulate the bias voltage coming from the video-cam as well, I'd expect. If it were me, I'd build one... but need to do more research first. If you have a Sony with a mic in a simple cord from Radio Shack will suffice. Unless you have an intercom that can't drive an 8 ohm load, in which case you'll get nothing on the tape and nothing in your headset. Or a fire in your intercom. Your intercom sees that Radio Shack cord as almost a short circuit. |
#5
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I have the PS Engineering PM 1000 II, the specs say the headphone
impedance range is 150-1000 ohms. Craig Prouse wrote: Newps wrote: wrote: I don't know of an off-the-shelf adapter, but it needs to be an impedance adapter. Headsets are typically 150-300 Ohm, with voltages running upwards of 10V. Portable devices like cd players and other line-in critters use a much lower voltage, and expect a lower source impedance. If you truly want to go into the mic port, it'd have to accept and modulate the bias voltage coming from the video-cam as well, I'd expect. If it were me, I'd build one... but need to do more research first. If you have a Sony with a mic in a simple cord from Radio Shack will suffice. Unless you have an intercom that can't drive an 8 ohm load, in which case you'll get nothing on the tape and nothing in your headset. Or a fire in your intercom. Your intercom sees that Radio Shack cord as almost a short circuit. |
#6
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On Mon, 14 Jul 2003 21:39:49 GMT, Bonanza Man wrote:
is there an adaptor that'll take the head-set audio-out of an airplane intercom into a jack that can be put into a standard microphone jack in a video-cam. I made one the quick and dirty way for my big trip. All I did was stick a big resistor in-line with the audio (actually a minature potentiometer, so I could fiddle with it). I initially underestimated the resistance needed (I thought it might be on the order of 5k ohms, I ended up using IIRC a 470K potentiometer maxed out). I just soldered the pot to the pin for the intercom jack tip, then the wire to the other end of the pot. The potentiometer fits inside the jack plug's cover, and a bit of heat-shrink rubber makes sure the exposed contacts don't touch the signal ground's pin. So you have intercom jack /-|============| 470K |---------------------left channel / |-----------------/\/\/\--|---------------------right channel stereo \ | | jack \_|============|------------ signal ground -------------------- It worked well. All the parts can be picked up at Radio Shack. I just butchered a stereo jack extension cable for the camera side, and soldered it into a nice screw-together large jack for the intercom. It is quick and dirty; I think the proper method is to have some form of impedence matching transformer, but I don't know whether such a beast exists that's suitable for intercom - camera. I also made a video camera stand which could be quickly attached to and released. It was basically a shaped polystyrene block (shaped to the curvature of the glareshield), which was velcroed to the panel. The camera was in turn velcroed to the top of the polystyrene block. It stayed on even during some of the severe turbulence I encountered crossing the Sierra Nevadas (multiple negative-g bumps which made my charts almost hit the roof) but was quick to pull off by hand. Make sure you don't site the camera too close to the compass - I did some testing to see where I could place the camera without causing the compass to move. -- Dylan Smith, Castletown, Isle of Man Flying: http://www.dylansmith.net Frontier Elite Universe: http://www.alioth.net "Maintain thine airspeed, lest the ground come up and smite thee" |
#7
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"Dylan Smith" wrote in message ... - I did some testing to see where I could place the camera without causing the compass to move. The testing is not sufficient. One of those places where the camera sits and keeps the compass from moving might keep it from moving even when the plane turns. |
#8
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Now that I got off on this tangent on intercom audio interfaces,
I'd suggest something like this for what you want (similar to previous post): Headset Plug Tip|----\/\/\/-----|====== Left/Right to cam | 680 \ | / 82 | \ Headset Ground |---------------|------ GND of cam That'll load it so it looks something like a real headset, but cut the voltage down by a factor of 10 or so. If you don't want to load your intercom, make it 6.8K and 820 Ohm. Adjust the 82 (or 820) size to plus/minus a factor of 3 or so if you need to adjust the volume. My guess it that'll do it. -Cory Dylan Smith wrote: : On Mon, 14 Jul 2003 21:39:49 GMT, Bonanza Man wrote: :is there an adaptor that'll take the head-set :audio-out of an airplane intercom into :a jack that can be put into a standard :microphone jack in a video-cam. : I made one the quick and dirty way for my big trip. : All I did was stick a big resistor in-line with the audio (actually a : minature potentiometer, so I could fiddle with it). I initially underestimated : the resistance needed (I thought it might be on the order of 5k ohms, : I ended up using IIRC a 470K potentiometer maxed out). I just soldered : the pot to the pin for the intercom jack tip, then the wire to the other : end of the pot. The potentiometer fits inside the jack plug's cover, : and a bit of heat-shrink rubber makes sure the exposed contacts don't touch : the signal ground's pin. So you have : intercom jack : /-|============| 470K |---------------------left channel : / |-----------------/\/\/\--|---------------------right channel stereo : \ | | jack : \_|============|------------ signal ground -------------------- : It worked well. All the parts can be picked up at Radio Shack. I just : butchered a stereo jack extension cable for the camera side, and soldered : it into a nice screw-together large jack for the intercom. It is quick : and dirty; I think the proper method is to have some form of impedence : matching transformer, but I don't know whether such a beast exists that's : suitable for intercom - camera. : I also made a video camera stand which could be quickly attached to and : released. It was basically a shaped polystyrene block (shaped to the : curvature of the glareshield), which was velcroed to the panel. The camera : was in turn velcroed to the top of the polystyrene block. It stayed on : even during some of the severe turbulence I encountered crossing the Sierra : Nevadas (multiple negative-g bumps which made my charts almost hit the : roof) but was quick to pull off by hand. Make sure you don't site the camera : too close to the compass - I did some testing to see where I could place the : camera without causing the compass to move. : -- : Dylan Smith, Castletown, Isle of Man : Flying: http://www.dylansmith.net : Frontier Elite Universe: http://www.alioth.net : "Maintain thine airspeed, lest the ground come up and smite thee" -- ************************************************** *********************** * The prime directive of Linux: * * - learn what you don't know, * * - teach what you do. * * (Just my 20 USm$) * ************************************************** *********************** |
#9
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I have a Sony Digital 8 camcorder. All you need is the attenuating
patch cord from Radio Shack. This plugs into the camcorder audio in. On the other end you need an adaptor so it will plug into the intercom audio out. Whole deal costs less than $10. Sounds great. Only down side is there is now no engine noise on the tape. To secure the camera I bought some elastic, comes in a long string. I tripled it up and attached it to a couple of ring terminals that attach to two screws that are part of an avionics access panel. The camera sits on top of a sponge. The sponge lifts it up slightly for a better view out the window, keeps the camera from moving and also totally eliminates vibration. Just remember to set the camera to focus on a distant object, not the nearest thing in front of it. Bonanza Man wrote: is there an adaptor that'll take the head-set audio-out of an airplane intercom into a jack that can be put into a standard microphone jack in a video-cam. |
#10
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Bonanza Man wrote:
is there an adaptor that'll take the head-set audio-out of an airplane intercom into a jack that can be put into a standard microphone jack in a video-cam. Aircraft Spruce P/N 13-01456, Patch Cord Cockpit Voice Recorder $24.95 See their catalog under "Headset Adapters and Extensions" I have one, works great. See also: P/N 11-00694, CD Player Adapter $29.30 Allows you to connect your CD player or other audio out source to your headset, while remaining connected to the aircraft radio. Ross Oliver |
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