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By Jack Ganssle
No More Wall Transformers
I'll present my Better Firmware Faster seminar in Melbourne, Australia February 20. All are invited. More info here.
As I write this my Sony Vaio computer's power supply is plugged into the boat's inverter. The portable drill's battery died this morning, so it's wall transformer is also connected to the same inverter. My daughter's CD player and the video camera both need charging but the bulky power bricks block access to the other outlets. Despite plenty of outlets, the physical size of the transformers limits us to plugging in but two devices at a time.
Aboard Voyager we have a special compartment filled with wall transformers. Each handheld radio has it's own special transformer, as do the tools, toys and computers.
I love my Vaio laptop; it's an inch thick and weighs only two pounds. On business trips a working computer is critical to me, so I always carry two in case of failure. A small briefcase is enough to carry both units with papers and other office trivia. But the infuriating tangle of wires from the power supplies almost doubles the volume of the travel kit. Why couldn't Sony put the supply inside the machine? Why can't Craftsman build the charger inside the drill?
Obviously vendors can build smaller and perhaps cheaper products by burdening the users with a plethora of external power supplies. But is this doing the consumer a real service? They get lost, rendering the product useless. Though most come plastered with the usual safety warnings, CE stickers and UL approvals, few have a label that matches each with the appropriate product. I've taken to writing in indelible ink on each so I know what device to use to charge the appropriate tool or whatever.
Why not build the power supply into the cord itself? A three-wire plug is big enough to house a bit of electronics. Modern switching power supplies are extremely efficient; the small wattages needed by rechargeable electronics eliminates any need for heat sinks.
BI Technologies (www.bitechnologies.com) advertises a tiny DC-DC converter. Feed the 110 VAC line into a bridge rectifier, the output to their model 830-004, and you've got 6 watts of DC from 5 to 18 volts, over an input range of 110 to 375 volts. That's plenty for recharging most small devices. Why not build this into the power cord itself?
Even better, why not standardize rechargeable appliance power requirements? OK, maybe I'm dreaming, but if all of our electronic marvels used identical connectors and voltages we'd have totally interchangeable charger cables. The same, small, cheap cable would charge your computer and razor. Toss just one or two in the travel bag instead of 5 pounds of tangled, application-specific, wall transformers.