DI Y

CIRCUITS

NET DATA METER

Antique voltmeter displays current air quality from the web. By Tom Igoe

One thing that disappoints me about computers is how little character they possess. Antique instruments of information display, like Victorian pendulum clocks, barometers, and compasses, and Babbage’s calculating engines, have a presence that modern computers lack.

Photography Tom Igoe

I dig the look of the iPod as much the next guy, but even the best manufacturing design today doesn’t match that old brass-and-hardwood handcrafted love. Desktop widgets replace the need for clocks, barometers and stock tickers, and multipurpose display hardware like the Ambient Orb also perform these functions. But because these things have little presence and are so easily reconfigured, it’s easy to forget what information they’re displaying. Does the meter’s sudden plunge mean my Google stock tanked, or that it’s going to rain tomorrow?

Many geeks, myself included, resist this trend by fanatically collecting old instruments for aesthetic reasons. I’ve been playing around with using antique instruments to display data from new sources. I have some beautiful, wood-encased voltmeters and ammeters from the early 20th century, which I rescued from my university’s physics department trash. They work quite well but they’re not as portable as my current multimeter, so I wasn’t using them, which is a tragedy for such proud, functional instruments. So I decided I’d take a cue from Ambient Devices ( ambientdevices.com) and make one of them into an air quality monitor.

First, I came up with the basic system. The meter I used is an analog voltmeter that ranges from 0–3V DC. That’s a good range to control from a microcontroller, so I decided to use my

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