[Lab] [Bulk] Wiring Project Feedback / Support

Ken klmckinnon at rogers.com
Wed May 1 20:55:38 EDT 2013

I think you are running into the USB Host versus slave issue.  For a 
host, it can provide +5VDC, and a slave expects that voltage.  A OTG 
(on-the-go) device detects and sources or sinks as necessary.   We have 
a few i-thingy's about the house, and I can not think of a peripheral 
where the i-thingy acts as host.  (to be fair, I don't have one, so 
speak from outside the circle).  There is a handshake routine where 
those things are decided assuming the drivers are present.
I would suspect the problem that you are having is that you can not 
power the mic as the mic is in slave mode and the i-thingy does not act 
as host, and/or there is no online driver for the USB interface of the 
mic for the i-family.
Hacking it to provide an analog interface may be possible, but since the 
output is digital USB your talking hacking at the hardware level inside 
the mic.
In addition, the line in/out would be non-powered.

I would suspect that your best option would be to look at a analog 
solution and provide voltage for the mic from a battery, inputting 
through your speaker/mic interface, but others may have better ideas.

As an aside, my colleagues and I were talking about the functionality of 
smartphone devices today and the capability of these devices being 
whatever you need with the barest of interfaces, just dependent on 
imagination.  You have an entire fairly powerful computer in your 
pocket....we live in interesting times!


On 5/1/2013 11:21 AM, Jamie wrote:
> Currently using a powered USB mic (Audio Technica AT2010 
> <http://www.audio-technica.com/cms/wired_mics/c75c5918ed57a8d0/index.html>) 
> with laptop to record podcast <http://steppinofftheedge.com>.
> Goal is to be able to connect it to iPhone to reduce gear size for 
> interview setup, but the powered part of USB is proving to be a 
> challenge. Tried using a USB Hub but no luck. I think instead of 
> having audio go via the 30-pin connector it has to send via the 
> headphone jack. Not sure if hitting an unpossible digital/analog wall 
> in this scenario. I have materials to hack an extra iPhone USB charge 
> wire, USB power wire and headphone jack together but hoping someone 
> can confirm what I'm trying to do is possible before I start down that 
> path.
> Related Links:
>   * Non-Powered Mic Hack:
>     http://benttronics.blogspot.ca/2009/05/audio-breakout-cable-for-ipodiphone.html
>   * iPhone 30 pin out guide
>     http://pinouts.ru/PortableDevices/ipod_pinout.shtml
>   * More context from a reddit thread on the idea a year ago:
>     http://www.reddit.com/r/AskReddit/comments/fmavw/solve_a_portable_microphone_challenge_win_for_you/
> I might be able to make it out to the modlab tonight and wondering if 
> anyone is going to be there with interest / time to help point the way 
> on this type of project?
> Thx,
> Jamie
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