Apple Inc announced the new versions of the "iPod nano" and "iPod touch" in September 2008. Both models feature slimmer chassis design compared with the predecessor models, with new functions such as an acceleration sensor and the "Nike + iPod" wireless link supported by the nano and the touch, respectively.

What does the inside of the slim chassis look like? Nikkei Electronics broke down the nano and the touch with a Japanese engineer who is engaged in reverse engineering the iPod series at an electronic component manufacturer in Japan. And we had him discuss the characteristics of the latest design as seen in the internal composition. We started with the iPod nano.

Q: The fourth-generation "iPod nano" has finally been released. The latest version is drawing interest with its slim 6.2mm thickness, which makes it the thinnest iPod, as well as its unique elliptical column chassis.

A: The price is also quite reasonable. As Apple doubled the amount of memory compared with its predecessor and is offering the new model at the same price, pricing an 8-Gbyte model at US$149, I feel that the new nano will sell quite well.

As for the inside, I got the impression that its internal design has become quite organized compared with the other models in the series. I'll explain some of its characteristic points.

The new iPod nano broken down (Click picture to enlarge)

First of all, more and more IC chips are now being customized and, in many cases, it is impossible to determine what manufacturer produced the IC just by looking at its surface. Apple seemed to have used many customized items and integrated many functions to reduce the nano's size and thickness.

The substrate's formation also became very complicated. Flexible cables are running out in four directions from the substrate, which is smaller than that in the predecessor. Due to the more complicated formation, it became impossible to rebuild the substrate once it is torn down, whereas we could somehow rebuild the substrate in the preceding model.

The flexible cables running out in four directions

The main substrate of the latest iPod nano has no ports for connection with those flexible cables. This seemed to be a result of cost-cutting efforts.

Q: Apple doubled the memory size and added new functions while further slimming the chassis.

A: I think one of the most significant features among the newly added functions of the latest nano is the incorporation of "an acceleration sensor." The nano that we broke down this time is embedded with the "LIS331DL" 3-axial acceleration sensor manufactured by Franco-Italian joint venture STMicroelectronics.

It is an ultra-small acceleration sensor that uses so-called MEMS technology. With this sensor, the nano must be able to detect finger taps on its surface.

I'm interested in what Apple is planning to do with the sensor, other than shaking the chassis to shuffle songs.