2008-06-14

A universal DC power adapter

Refresher: alternating current (AC) is what comes out of a wall socket, while direct current (DC) is what devices such as iPods need for charging etc. To translate between the two, you need a power adapter.
Currently, power adapters have the following problems:
  • Wasting materials: Every time, a plug changes, old adapters still in sales/production circulation will have to be discarded. Furthermore, sharing adapters could, say, halve their number. Theoretically, standardization would also make production more efficient.
  • Wasting energy: Many old, less energy-efficient, adapters are still in use, because one cannot upgrade them (due to their proprietary plugs). Also, devices have no way of signalling the adapter when they are done charging.
  • Lack of convenience: Non-standard plugs means you cannot share the same power adapter between devices and that once a proprietary plug falls out of fashion, you might not get a new power adapter for it, any more.

A company calleed GreenPlug has come up with a nice solution:
  • A standardized plug: It builds on the USB plug (which is slowly becoming a kind of DC standard), so its adapter can charge USB devices.
  • A protocol for communicating power needs: If a device is aware of the GreenPlug adapter, it can use the Greentalk protocol to completely shut the current off once it is done charging.
They make their money by selling adapters, so not all of the problems outlined above are completely solved by the GreenPlug, but it is still a great idea. Non-standard plugs have been irking me for a long time, so it is great that someone finally does something about it. In the future, one can even imagine having GreenPlugs as wall sockets, at home and at public places which may completely obviate the need for DC power adapters.
More information on GreenPlug (and my original source):