Can anyone help make some informed guesses about a remote control for a portable digital recorder? I want to hack a wireless version and need to know how it works.
The recorder is a Zoom H4N (
http://www.sweetwater.com/store/detail/H4N), which has a 1/8"=3.5mm jack for a remote. The wired remote (
http://www.sweetwater.com/store/detail/RC4) made by the manufacterer has a 4-connector plug, like an old iPod Shuffle or an iPhone 3 headset. The remote appears to have 12 buttons controlling several functions. It also has 3 LEDs indicating which input channel is selected, so it is evidently getting something back from the device.
There are some contraints in working on this: This is for a friend; I have access to his recorder but do not feel comfortable opening it because he depends on it professionally and I can't risk damage or voiding the warranty. I also don't have the company's remote itself (which costs $40 that I am trying not to to spend) to mess around with. So I have to guess about how the remote works then try things out non-destructively.
I can imagine various ways this could work, all of which have problems as theories.
--One is that one connection is a ground and that the device looks for various resistances from ground to the three terminals. I know some camera remotes and iPod connections work this way to signal various states on one circuit, switching in resistors of different values.
--Another would be a keyboard encoder on the remote so that it presents binary words representing the various button presses.
--Yet another would be serial data exchanged with the device. Given that there's almost certainly a processor in there, this wouldn't necessarily be hard for the designers to implement.
Any experience out there with similar devices? Thanks for any ideas. --Dan M