(FORTUNE Magazine) – Cambridge, Mass. Founded 2001

After several years of tinkering, "smart dust" networks--tiny, cheap, low-power computerized sensors that can monitor light, temperature, and motion--are primed to blow out of the lab and into industrial, military, medical, homeland-security, and consumer applications. Few companies are better networked than Ember, a startup that counts Ethernet pioneer Robert Metcalfe as a backer.

Ember already boasts a roster of some 100 customers, including giants like Philips and Honeywell International, which want to put Ember's smart chips into a host of wireless applications. Current tests involve everything from hospitals to office buildings to a Las Vegas casino. Ember expects to ship 20 million chips over the next two years, feeding a market that will grow to almost $2 billion by 2007. Later this year an Ember-enabled air conditioner, which can be monitored remotely, is slated to hit home retailers. That brings new meaning to "cool." --Matthew Boyle