My responses are inline and bolded :
@neutron_bob wrote:
The biggest problem with adding the Sansa and an FM transmitter to a CAR is that there are many variables in the equation.
Not all automobiles treat that cigar lighter socket, or “power outlet” as it is also named, with the same respect.
In many cars, the lighter socket is live 24 hours a day, with its own dedicated fused circuit. In others, it is activated when the ignition is switched on.
I can see this being problematic with my suggestion. I can only go by my own experiences that cars that I have owned over the past 15 years, which were built in the last 15 years have power outlets (i.e. cigarette lighters) that are only powered up when the car is running.
That’s just the simple ones. Today, power management is evolving. That outlet is becoming computer-controlled, in the interest of efficiency. It’s possible to have the outlet live until the driver door is opened, after removing the key, or live for a timed duration of anything up to 30 minutes on average. Then, we can add “load shedding” designs. In this design, while the starter motor is drawing over 120 Amperes, all unnecessary circuits are interrupted during the start cycle: the wipers, hadlights, rear window defroster, supplemental heat, and cabin fan are turned off until the engine starts, including, yes, the power outlet in some applications.
My wife’s car and my car do this which I know for a fact because the portable DVD player my son uses when we go on long trips does not keep its place in the movie so when I re-start the car, even from the “Accessory” setting (which keeps the outlet powered) it shuts my son’s DVd player off momentarily and he has to scan through the movie to get back to where he was. When it comes to listening to my MP3 player, however, this should not be a big problem because, typically, I would not be listening to music during this time. The times that I do have the “Accessory” on (to keep the power outlet powered up) I can deal with restarting the music. I actually turn off my car, get out and run into a store/restaurant/wherever much more often than sit in my car with the engine off listening to music and the only time that I really do that on a consistant basis is when I am waiting for my commuter train, in which case, I don’t re-start the car, I turn the car completely off, and head to the platform when the time gets close to when the train comes.
As far as the timed or door controlled power outlet, I have not heard about that. I know that manufacturers have been powering radios like that, but I have not heard about power outlets that do that. After thinking about this a bit, I do not see the problem with the door turning off power to the power outlet. That would just cause the MP3 player to pause when the door was opened vs. when the ignition is turned off. Also, pausing the MP3 player after a set time, while it could be problematic from a standpoint that you still have to hit pause when you leave the car so that you can continue listening to your song/book/album/whatever where you left off, at least the battery would not drain on your MP3 player should you be in a rush and forget to pause it. This happened to me with my other MP3 player, of which there is no manufacturer’s specific FM transmitter.
Manufacturers of automobiles have realized that the venerable “power outlet” plays host to a myriad of electronic devices now, so the little (well, not so little, actually) sockets are popping up in unique locations, the trunk, the rear seat, the front, center, and rear of the console, or even in trios in some trucks. Folks are charging their laptops with them, the kids are playing DVDs and playing electronic games in the rear seat, and GPS devices are being plugged in.
Granted, but not an issue. I find it unlikely that someone listening to their MP3 player via an FM transmitter through their radio would be powering it from an outlet intended for people in the rear seats to use or an outlet in the trunk. The most likely scenario would be that someone in the backseat is listening to their MP3 player through headphones and there it is highly probable that that person can remain in the backseat listening to their MP3 player with the car completely turned off, but was using the power outlet to charge the player. This would be a good reason for my suggestion to be incorporated as a user selection, if possible, otherwise, when used in this scenario, there is the possibility (if the outlet used is powered off when the car is powered off) that the user would have to un-pause their music.
Knowing this, the outlets are not all live at the same time, and some protect the outlet from the nasty electrical spikes generated in the start process (the starter is a nasty inductor, and so are electric motors when turned off, plus solenoids).
I will have to confirm this, but I only have two power outlets on the front console, none anywhere else in my car and I am 99% sure that both come on and go off with the ignition switch and are turned off while attempting to start the car. I owned one car, by a different manufacturer than our current cars, that had an electrical power outlet in the trunk, but did not own it long enough (it was totalled 6 mos. after I bought it when someone went through a red light and hit me) to find out if it behaved similar to two power outlets up front, which both did turn off with the ignition and on startup of the engine.
Back to the point of all this information: can you see that enabling a “pause” can be problematic, since not all users will experience the same behavior?
I do not know if it is problematic or not. I will say that, taking into consideration what you have said, I am not sure what the Zune sees in order to determine that it needs to pause the player, but I do not see where being able to pause the Fuze or any other MP3 player when the FM transmitter is clearly no longer transmitting would be a problem. Perhaps it is not as easy as sensing power, as I assume the Zune is doing, perhaps there is something more to it, but I think that is one feature that the Zune, coupled with a Zune specific FM transmitter, has that Sansa should try to incorporate into their line taking advantage of the Sansa specific FM transmitters. Again, ideally, I think this should be implemented as a user selection feature that the user can turn on or off depending on the how a particular user chooses to use their Fuze or any Sansa MP3 player.
Bob 
