Now that we got rid of all buttons, we’re taking a hard look at the connectors and slots offered by the Redux Model 1, trying to limit their number to the bare minimum, or to get rid of them altogether. This is a pretty radical approach, but our device is a pretty radical one anyway, so why not?
Until now, our marketing requirements called for five connectors and slots: mini USB, audio in, audio out, SD card, and SIM card. Let’s go through them methodically, and for each of them, let’s try to find a reason why we would absolutely need it. If we cannot, let’s just get rid of it, once and for all.
The mini USB plug serves two purposes: data exchange and battery charging. While the former could be done wirelessly, there is no practical way of doing the later without any wires. Of course, we could use some inductive power transfer technology, but the kind of base station required to make it work is so bulky that it would defeat the mobility purpose that is driving our overall design.
The connectors for audio in and audio out could be replaced by Bluetooth 2.0. In transmit mode, the Wi2Wi W2CBW003 chip we are using for 802.11b/g and Bluetooth 2.0 consumes about 148mW, which is just twice as much as what the LM4857 stereo amplifier from National Semiconductor requires for typical use with stereo headphones, making Bluetooth 2.0 an acceptable alternative for audio in and out. And for watching movies during long trips, the tablet is likely to be used in conjunction with its magnetic keyboard, which will incorporate a standard 3.5mm stereo headphone minijack.
This leaves us with the SD card and SIM card slots. Two options are available: open slots on the device’s edge, or hidden slots on the internal PCB. While the first option brings convenience, the second makes for a simpler and cleaner industrial design. On one hand, regular swapping of the SIM card is not a requirement for most users, therefore hiding the slot inside the device should not create too much of an inconvenience. On the other hand, many users like like to carry multiple SD cards full of music and videos, and not having the slot easily accessible would not support such a scenario. Nevertheless, the rapidly increasing storage capacity offered by SD cards (Cf. article) makes it so that one card can hold pretty much any file the device could take advantage of, and all we might need is to make the card’s content easily accessible when plugging the tablet to another computer through its USB port.
Should we adopt such an approach, we would reduce the number of connectors and slots from 5 to 1, leaving just the mini USB port, to be located on the bottom edge of the tablet when used in landscape mode (landscape docking only). Now, we need to figure out whether a mini USB port is the best connector for it, or whether we should go for a standard iPod/iPhone connector instead. More on this soon.