University team is perfecting the art of hijacking power from the iPhone's headphone jack

The University of Michigan's Project HiJack harnesses power by using bandwidth from the iPhone's headphone port. There are actually some peripherals that do this already -- think Square's credit card reader -- but Project HiJack sees this expanding to produce sensors for blood pressure, glucose, carbon monoxide and more. Right now, their work is very basic, but they are producing data transfer results through the headphone jack.

Check out Project HiJack's work in action after the cut.

[via Engadget]

Hijacking Power and Bandwidth from the Mobile Phone's Audio Interface - Integrated Prototype from Thomas Schmid on Vimeo.

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Source: http://eecs.umich.edu/~prabal/projects/hijack/

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The University of Michigan's Project HiJack harnesses power by using bandwidth from the iPhone's headphone port. There are actually some...

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CAVEperson

Very nice tech demo, but not practical. Button cells are small, cheap, lightweight, and produce vastly more power than this "hijacking" is capable of.

January 18 2011 at 10:40 AM Report abuse Permalink rate up rate down Reply

Zimmie

Square's card reader does not "hijack power", it is a magnetic microphone. It's just a magnetic read head wired up to the headphone jack just like any other microphone would be. Works just like a normal dynamic mic.

January 17 2011 at 7:48 PM Report abuse Permalink rate up rate down Reply

2 replies to Zimmie's comment

llamatronique

I think you mean capacitive, not magnetic. The iphone jack puts out a bias voltage on the mic input for driving condenser/mems capsules.

But that's not what they're doing, they're using a tone on the headphone output and using the audio output as a power source (sort of like a pwm switch mode power supply).

January 17 2011 at 10:55 PM Report abuse Permalink rate up rate down Reply

llamatronique

Yes, I misread your post.

January 17 2011 at 10:59 PM Report abuse Permalink rate up rate down Reply

SIP

I'd love to be able to just plug in my Blood Glucose meter into the iPhone, save the data, sync with iTunes and then transfer it to the iPad. The tech is already available, just needs someone to produce a reasonably priced device.

January 17 2011 at 7:04 PM Report abuse Permalink rate up rate down Reply

Jon

Why bother when you can use bluetooth?

January 17 2011 at 3:16 PM Report abuse Permalink rate up rate down Reply

1 reply to Jon's comment

Tristan OTierney

Because bluetooth is a cumbersome experience and drains batteries on the external peripheral.

January 17 2011 at 3:18 PM Report abuse Permalink rate up rate down Reply