Hardware hacking -- Antennas, jacks, and power-sensing

Hiyo,

  First, greetz to all in cdfreakland, I'm looking for contacts to discuss a project with.  Second, for my project, the closest analog is an mp3 player since the device has a signal out (but it also has pcb antenna and ferrule for switching to external antenna) .... my question, a) is it feasible to use power-sensing circuitry to switch on device functions by using altered electrical characteristics of connectors (Ie, to switch from an internal to external antenna when screw is attached or to turn the device on automatically when a jack is plugged into the device's audio connector) ?  b)  where can I get the standards or a guidebook to understanding signal transduction for the purpose of headphones or pre-amplified stereo system line-in/aux signalling?  Any ideas?  Thanks for feedback....    :bow:

Umm…you might want to check with something like the AVS forum since this is mainly a “CD/DVD” forum. You can probably use an analog/RF switch to toggle between the internal and external antenna, but you should make sure the switch is capable of matching the impedance and/or circuit with regards to the RF integrity since you want to minimize any potential dB loss.

[QUOTE=stereofan;2221304]a) is it feasible to use power-sensing circuitry to switch on device functions
b) where can I get the standards or a guidebook to understanding signal transduction for the purpose of headphones or pre-amplified stereo system line-in/aux signalling?[/QUOTE]a) I’m sure this can be done because my Zune goes to Pause when the headphones are removed.

b) I found this:
The best technical reference is The Loudspeaker and Headphone Handbook by John Borwick (1994, 2nd ed) over at HeadWize with a Google search on “Headphone Standards”. I am pretty sure that there are some IEC (International Electrotechnical Commission) standards for interaction between amplifiers and speakers. Try googling IEC headphone standards.