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Projects: hijack (Hijacking the iPhone earphone jack)

eecs.umich.edu

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Re: Projects: hijack (Hijacking the iPhone earphone jack)

#11

Post by Timothee »

I think it's a very interesting project. I've been very interested in things that combine hardware with smart phones, since the Apple keynote that showed the first authorized hardware "extensions". (though since then, I've been disappointed in not seeing much of anything)

However, can anyone chime in about the differences there are between using the iPhone jack and using the dock connector? I know you're supposed to fill out some docs with Apple to officially hack on the dock connector, but I believe you can find hardware to do that without Apple's consent. It looks like one would have to go the jailbreak route with that project as well.

I imagine the main thing is that a hobbyist can much more easily/cheaply get a jack connector than a dock connector...

Re: Projects: hijack (Hijacking the iPhone earphone jack)

#12

Post by unoti »

That's truly amazing what they're doing here. I'm sorry if this is an ignorant question, but wouldn't it make sense for there to be some kind of USB port or something that's actually designed for I/O on the iPhone? I mean, surely there'd be less power loss if the port was actually designed to power other low power devices. Especially if it could mean that you don't need as powerful of an external microcontroller for doing the hacking and encoding that's necessary for doing all the work-arounds from not having a real IO port.

Re: Projects: hijack (Hijacking the iPhone earphone jack)

#13

Post by gonzo »

frankus wrote: post #7

Also check out the Southern Stars SkyWire. Apparently it's a true RS-232 I/O cable that plugs into the dock connector. They use it to drive telescopes, but apparently it's not limited to that. http://www.southernstars.com/products/skywire/index.html I've gotten as far as opening an input and output stream with it, but I haven't had time to dig up an RS-232 device to try talking back and forth.

These are made by RedPark

Re: Projects: hijack (Hijacking the iPhone earphone jack)

#14

Post by acgourley »

unoti wrote: post #12

That's truly amazing what they're doing here. I'm sorry if this is an ignorant question, but wouldn't it make sense for there to be some kind of USB port or something that's actually designed for I/O on the iPhone? I mean, surely there'd be less power loss if the port was actually designed to power other low power devices. Especially if it could mean that you don't need as powerful of an external microcontroller for…

Apple wants you to use their 30 pin interface, but that requires going through their MFi program and that lets them control the hardware ecosystem like they do the software ecosystem.

To be fair, there are certain advantages to hardware manufacturers willing to jump those hurdles. You're able to ensure no one can make software for your hardware, for one. Secondly users who plug in your hardware can automatically be taken to the app store to download your software.

Re: Projects: hijack (Hijacking the iPhone earphone jack)

#15

Post by acgourley »

frankus wrote: post #7

Also check out the Southern Stars SkyWire. Apparently it's a true RS-232 I/O cable that plugs into the dock connector. They use it to drive telescopes, but apparently it's not limited to that. http://www.southernstars.com/products/skywire/index.html I've gotten as far as opening an input and output stream with it, but I haven't had time to dig up an RS-232 device to try talking back and forth.

Unless you have a jailbroken device, arbitrary apps you write won't be able to access that stream.

Re: Projects: hijack (Hijacking the iPhone earphone jack)

#16

Post by acgourley »

7.4mW is more power than I would have thought possible. That is really cool. Plus with some additional hackery you may be able harvest up to double by toggling the second audio channel on and off when you don't need to receive data from the phone.

I'm going to put together a board based on their specs. If anyone in the bay area is interested in collaborating on a project with it shoot me an email.

Re: Projects: hijack (Hijacking the iPhone earphone jack)

#17

Post by frosty »

acgourley wrote: post #14
unoti wrote: post #12

That's truly amazing what they're doing here. I'm sorry if this is an ignorant question, but wouldn't it make sense for there to be some kind of USB port or something that's actually designed for I/O on the iPhone? I mean, surely there'd be less power loss if the port was actually designed to power other low power devices. Especially if it could mean that you don't need as powerful of an external microcontroller for…

Apple wants you to use their 30 pin interface, but that requires going through their MFi program and that lets them control the hardware ecosystem like they do the software ecosystem. To be fair, there are certain advantages to hardware manufacturers willing to jump those hurdles. You're able to ensure no one can make software for your hardware, for one. Secondly users who plug in your hardware can automatically be t…

Also the headphone jack is available on all phones and if you develop for 30 pin interface, you have to design different hardware connector for different phones

Re: Projects: hijack (Hijacking the iPhone earphone jack)

#18

Post by acgourley »

nickolai wrote: post #3

Cool project! Currently, I am a bit doubtful concerning whether drawing extra power from an already very battery lifetime-constrained smartphone is a good idea. On the other hand, the batteries shold improve in the future, so with a bit of luck the idea may just as well come to maturity at the right time!

From their paper:

"To estimate the impact of energy harvesting on the phone, we modifying an iPod Touch to measure battery current and voltage. We play an audio file that generates the required 22 kHz tone and find that the iPod draws 91 mA at 4.04 V when the harvester is attached and 37 mA at 4.04 V when the harvester is not attached.

These figures illustrate the substantial inefficiency of this approach compared with directly supplying power to a peripheral. We note, however, that the power output of an iPod is higher than an iPhone, making the numbers appear worse than they are on the iPhone."

Re: Projects: hijack (Hijacking the iPhone earphone jack)

#19

Post by acgourley »

simonk wrote: post #10
jrockway wrote: post #6

Now if only you were permitted to write software to take advantage of the cool hardware you build.

Square has their app on the marketplace. https://squareup.com/

Worth noting they may have had to go through additional testing. When you submit an app that needs MFi hardware, they make you submit the hardware as well and test both together. They may have demanded something similar for Square.

Also worth noting that square is not drawing power, doing so might make them reject your app. Especially because this harvest method is fairly inefficient (power is being converted twice before its useful). Draw on the iphone battery may be 4x the power used.

Re: Projects: hijack (Hijacking the iPhone earphone jack)

#20

Post by joe_bleau »

acgourley wrote: post #14
unoti wrote: post #12

That's truly amazing what they're doing here. I'm sorry if this is an ignorant question, but wouldn't it make sense for there to be some kind of USB port or something that's actually designed for I/O on the iPhone? I mean, surely there'd be less power loss if the port was actually designed to power other low power devices. Especially if it could mean that you don't need as powerful of an external microcontroller for…

Apple wants you to use their 30 pin interface, but that requires going through their MFi program and that lets them control the hardware ecosystem like they do the software ecosystem. To be fair, there are certain advantages to hardware manufacturers willing to jump those hurdles. You're able to ensure no one can make software for your hardware, for one. Secondly users who plug in your hardware can automatically be t…

Is there anyplace online people in the MFi program hang out (forums, usenet, mail lists, etc.)? I've got some very basic questions about the whole process, but it seems like such a black hole (from the outside looking in).

It would be great to use the ipods or ipads for industrial data collection, but we'll need IR and a way to get data on/off without network connectivity.

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