Saturday, September 22, 2012

Frankenpod v2

I'm so flattered to have my post on Frankenpod featured on hackaday. However, the full disclosure is that I had finished the project a couple of months ago and had only just gotten around to writing about it.

I loved Frankenpod v1, but its main issue was build quality. The hot glue broke down after a while, requiring frequent repairs, and I also missed the ability to sync the player with iTunes (the player showed up as an external drive where you can drag and drop music onto it; some people prefer this system, I personally like to use iTunes). This reminded me about the solid state iPod Mini hack.

The original iPod Mini CF Hack

It turns out that the connector in the iPod Mini to its 4gb microdrive is the exact same connector used to interface with a compact flash card. This meant that you could easily replace the drive with a CF card, making the iPod solid state. Why do this? The reasons are twofold: more space (large flash memory cards are exceedingly cheap) and increased battery life (CF cards have no moving parts, so it takes less power to use them).

Since iPod Minis stopped being sold around 2006, you can pick them up for relatively little money. I went ahead and bought one, along with a 32gb CF card and a higher capacity after-market battery.

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Our helpless victim

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Unlike Frankenpod v1, this hack required little actual hacking. The only snag I encountered was when replacing the battery. The iPod I bought was refurbished, and the seller had soldered in the original battery to connector. Since I couldn't easily remove the original battery, I ended up snipping the cables and soldering the new battery in. I then pieced everything together and plugged it into my computer.

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The original battery

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iTunes may immediately recognize the device, but the first thing you should do is reformat the drive. I found this easiest to do in Windows without having iTunes installed. The drive should mount and you can reformat it to whatever the default format Windows suggests (FAT32?). Once reformated, plug the device into a computer with iTunes on it and iTunes should tell you that it needs to reflash the firmware onto the device. Once flashed, you're good to go!

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Success!

Here's another tutorial that goes into more depth about the formatting process.

Sunday, September 9, 2012

Frankenpod

I love listening to music while I work on projects and I was without a music player since the audio jack on my iPod broke. Using some money left over from an amazon giftcard, I decided to try out the Sansa Clip Zip. The device was super-cheap, could have its memory expanded with a micro sdhc card, and got great reviews on head-fi, so I was sold.

After the Zip arrived in the mail, I installed Rockbox. For those who don't know, Rockbox is an open source firmware that can be loaded onto a variety of media players. The best way to describe it is like linux for media players--its user interface leaves a bit to be desired, but it has support for practically every audio format under the sun and is delightfully hack-able.

Once I got used to Rockbox, I was happy with the device except for one gripe: the battery life. My old iPod got 20+ hours of playback per charge and the clip zip only got about 15 hours. I remembered reading a guide for replacing the battery on the clip zip, so I wondered if I could replace the battery with a larger capacity battery.

Research showed that the clip zip's battery had a somewhat common voltage for rechargeable batteries (3.7 volts) and that increasing the battery capacity would have little effect on the performance of the device. I found a cheap 3.7 volt LiPoly battery on amazon and ordered it. (in retrospect, this would probably have been a better battery to buy)

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The battery I bought was a replacement cell phone battery, so the first thing I did was to remove the casing surrounding the battery and remove the charging circuit.

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A quick word of caution here: BE CAREFUL. In general, you shouldn't take apart batteries. They have nasty chemicals inside, and if you use conductive, metallic pliers like me, it's easy to short circuit things. In my case, it turned out that the entire metallic casing of the battery was one of the electrodes, so I quickly insulated it with kapton tape.

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One thing to notice is that the Clip Zip has 3 wires connected to the battery, not two. This is for the charging circuit. In general, most electronic devices with rechargeable batteries contain a charging circuit which ensures that you don't over-charge the battery when you have it plugged in for an extended period of time. The trick is to connect the battery to the charging circuit, not directly to the device.

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Once I got everything soldered together, I tried booting the device. Everything seemed to look okay, so I insulated all of the components and tried fitting it back into the original device housing. I forgot that larger capacity batteries mean physically larger batteries, so I had to expand the device housing with hot glue and aluminum tape. Sure, it makes the industrial designer inside all of us cringe and has an uncanny resemblance of an IED, but it has that hacker appeal!

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After using the zip for a couple of weeks, I can happily say that the hack caused a substantial increase in battery life. The original battery was 300 mah and lasted for approximately 15 hours of playback. The new battery is 1100 mah and lasts for 50-60 hours of playback. Given that I only listen to it for a couple of hours each day, that means I can go at least 2 weeks between charging. That, coupled with the total project cost of approximately $50 for the device, battery, and 16gb micro sdhc makes me a very happy hacker (I'm able to get 2.5x the storage space of the ipod touch at 1/4 of the cost)!

:)

(I apologize for the lack of posts. I've been making the transition to college. Hopefully more posts will come soon!)