I'm interested to learn how some of iPod accessories communicate.
I have one that plugs into the headphone jack - I was thinking of running it through a headphone extension cable, and exposing the wires inside the cable. I think I could attach something like the Salae Logic 8-channel logic analyzer available here and get a picture of what's going on. And then ... noodle on that for a while to figure out whatever I can.
Would that be a helpful tool for this purpose?
Would the DSO Nano oscilloscope be better? worse?
If anyone has any suggestions about how I could start to see (and interpret) what's happening on those lines, I'd love to hear.
I expect it to be a bit of work ... just looking for tools to help.
Logic Anaylzer for iPod accessories?
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- brucef
- Posts: 215
- Joined: Tue May 03, 2011 4:51 pm
Re: Logic Anaylzer for iPod accessories?
I'd start by reading up a bit on Project Hijack. They've done a bunch of the work for you on this.
- harber
- Posts: 3
- Joined: Thu Oct 11, 2012 7:49 pm
Re: Logic Anaylzer for iPod accessories?
Thanks for the pointer, Bruce! That Project Hijack looks pretty cool.
Too bad the hardware is not available, but I'll read their papers and see what I can learn.
It looks the "analog or digital" question depends on the device plugged in - it seems the phone could handle either one.
So, I'm still not sure if I want a logic analyzer or an oscilloscope.
Off to do some reading - thanks again!
Too bad the hardware is not available, but I'll read their papers and see what I can learn.
It looks the "analog or digital" question depends on the device plugged in - it seems the phone could handle either one.
So, I'm still not sure if I want a logic analyzer or an oscilloscope.
Off to do some reading - thanks again!
- brucef
- Posts: 215
- Joined: Tue May 03, 2011 4:51 pm
Re: Logic Anaylzer for iPod accessories?
No problem... I saw that project a while back and it took a bit to dig it out of the corners of my Google-extended memory banks.
The hardware is available to purchase if you want, over at Seeed Studio. But yeah, if you're looking to answer the analyzer/scope question, the Hijack documentation looks like the place to start.
(and no, forumbot, this post is not spam.)
The hardware is available to purchase if you want, over at Seeed Studio. But yeah, if you're looking to answer the analyzer/scope question, the Hijack documentation looks like the place to start.
(and no, forumbot, this post is not spam.)
- harber
- Posts: 3
- Joined: Thu Oct 11, 2012 7:49 pm
Re: Logic Anaylzer for iPod accessories?
To summarize the parts of the paper that bear on this question:
*Anything using the headphone jack is kind of a hack (which, of course, is awesome, but leaves all the details up in the air).
*It'll use the mic channel as signal from the device to the phone
*It'll use the two audio channels: one for power (by an app on the phone generating a tone, which is just a voltage, after all) and one for signal from the phone to the device.
So, scope or logic analyzer? Depends on the thing you're trying to get between.
*If you think that thing will send analog to the phone, you'll want an oscilloscope.
*If you think it sends digital, the logic analyzer's your thing.
So. I just need to decide which way I want to bet, and run with it.
*Anything using the headphone jack is kind of a hack (which, of course, is awesome, but leaves all the details up in the air).
*It'll use the mic channel as signal from the device to the phone
*It'll use the two audio channels: one for power (by an app on the phone generating a tone, which is just a voltage, after all) and one for signal from the phone to the device.
So, scope or logic analyzer? Depends on the thing you're trying to get between.
*If you think that thing will send analog to the phone, you'll want an oscilloscope.
*If you think it sends digital, the logic analyzer's your thing.
So. I just need to decide which way I want to bet, and run with it.
Please be positive and constructive with your questions and comments.