Rockbox General > Rockbox General Discussion

Can any of the supported players detect headphones?

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ToneDeF:
Does anyone know if it is technically possible for any of the supported players to detect the presence of headphones -- especially the ability to distinguish between headphones and speakers?   :-\

Perhaps if the impedance load of the connector attached to the headphone port could be determined, it might be possible to determine whether headphones or speakers have been plugged into the headphone port.  I'm not sure what the impedance load range is for headphones versus (portable) speakers -- for this to be a viable detection method, I suppose there would need to be no overlap in impedance ranges for the two different types of devices in order to be able to distinguish between them.

Any other detection method ideas?

saratoga:

--- Quote from: ToneDeF on October 17, 2007, 11:59:06 AM ---
Perhaps if the impedance load of the connector attached to the headphone port could be determined, it might be possible to determine whether headphones or speakers have been plugged into the headphone port.  I'm not sure what the impedance load range is for headphones versus (portable) speakers -- for this to be a viable detection method, I suppose there would need to be no overlap in impedance ranges for the two different types of devices in order to be able to distinguish between them.

--- End quote ---

Portable speakers that don't have batteries should present the same impedance as headphones, otherwise they would be very quiet or might even damage the player.   I don't know of any devices that can check, but I suppose if you found one, you could at least detect amplified speakers via the line in impedance.  

ToneDeF:

--- Quote from: saratoga on October 17, 2007, 12:36:19 PM ---Portable speakers that don't have batteries should present the same impedance as headphones, otherwise they would be very quiet or might even damage the player.   I don't know of any devices that can check, but I suppose if you found one, you could at least detect amplified speakers via the line in impedance.  

--- End quote ---

Thank you for your valuable input.

If you're curious as to why I posed this question, I am running Rockbox on a Sansa e200R and thought it would be a nice feature if the crossfeed mode of Rockbox could be auto-enabled/disabled based on the type of device connected to the headphone port.  As I understand it, the crossfeed mode was primarily designed for headphone output.  For us lazy folks, the ability to automatically enable/disable the crossfeed mode would come in handy when you only want it enabled when headphones are connected.  I realize that this feature would not be doable unless at least one of the Rockbox-supported players (preferably my Sansa) had the capability to determine when stereo headphones are connected to the player.

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