Joshua Hoblitt schrieb: > On Mon, Feb 12, 2007 at 01:34:51PM +0200, Mikko J Rauhala wrote: >> I do also appreciate that adding Bluetooth back in wasn't trivial, but >> it does make the first edition much more useful (esp. local wireless >> internet, in lieu of wifi), so thanks for reacting to those requests. > > Quick thought: Shouldn't wifi be possible via the use of a USB "dongle"?
Pretty sure not. >From my experience WiFi USB dongles really suck tremendous amounts of power. The problem with USB is that it uses +5V power supply, which is quite uncommon in embedded portable devices - here you mostly have 3.3V or even 2.5V. So what you need to power USB devices is a step-up converter from low voltage to higher voltage. Those chips are quite inefficient and the higher power you want to supply the more space you need for external analog parts, like capacitors and coils. So buttomline is that +5V for powering external USB devices is too "expensive" in terms of extra parts and precious space inside the device - not even counting in the extreme high power consumption it would cause. I assume unless some genious invents a much higher efficient step up converter you will not see any small portable device to support bus powered USB devices. The low power stuff like SD/IO seems much more reasonable in this respect... > -J Cheers nils faerber -- kernel concepts GbR Tel: +49-271-771091-12 Sieghuetter Hauptweg 48 Fax: +49-271-771091-19 D-57072 Siegen Mob: +49-176-21024535 -- _______________________________________________ OpenMoko community mailing list [email protected] https://lists.openmoko.org/mailman/listinfo/community
