I've long wished for centralized backup power in the house for the ubiquitous small devices that run on low voltage with power adapters. Why not have USB charging outlets that reach back to a backup storage battery in the basement? Then clocks, modems, WiFi routers, and wireless phone base stations could all work when the power fails.
USB only supports up to 3 meters of data transfer. To use the USB network to transfer data, which would be a reasonable extension if a home USB charging network is in place, the USB standard needs to be modified.
Here's what the Patrick Manning, CEO of Current Werks llc has replied in part: "Our product is more efficient than the typical 'wall warts' that have become so ubiquitous...Our product ships with the receptacle already attached in a 15 or 20amp format. We have found that our customers appreciate the improved aesthetics of an office or home with far less square black transformers hanging from outlets."
Again, that's what the setup I got does. It replaces a switch cover for a double gang box, providing six AC outlets and a couple of USB drops. I've been very impressed with it. I even saw one that has a little shelf on it to park your cell phone.
The one that I got does this as well. I noticed that if I left the USB cord plugged in after unplugging the device then it shut down the port after some period of time. There must be a mechanical switch combined with a current flow sensor. Unplugging and replugging the cord reactivated the port.
Why does this REPLACE an outlet? Why not simply plug it into an existing outlet? Makes the device portable and avoids the time, effort, and cost of rewiring. I'm also baffled by the comment that this device is "compatible with 15Amp and 20Amp wall receptacles". Wouldn't it be compatible with any wall receptacle? It uses a fraction of an amp.
All vendors should seek ways to avoid power consumption by their devices when no useful work is being done. Having the closed cover eliminate standby power is a nice first step - but circuits should be designed to shutdown with no power consumption if there is no demand. Obviously there is no demand if there are no devices plugged into the USB connectors. Why not use that as the shutdown criterion?
Blog Doing Math in FPGAs Tom Burke 23 comments For a recent project, I explored doing "real" (that is, non-integer) math on a Spartan 3 FPGA. FPGAs, by their nature, do integer math. That is, there's no floating-point ...