On Monday Apple is expected to announce more details about the Apple Watch. It could be the product that finally brings wearable computing into the mainstream. But as far as high-tech watches go, it's hardly the most ambitious.

In 1972, the Hamilton Watch Company announced the Pulsar Time Computer, billed as the first digital watch. In the video above you can see—and hear—how grand the company's vision for the future of timekeeping was.

"Time. The endless river," the ominous voice intones as a clock ticks in the background. "Transporting some. Engulfing others. A stream upon which information explodes, communications multiply, technology accelerates into ever new life."

The "Time Computer" bit was mostly marketing hype. It didn't double as a calculator or address book, or have any of the other bonus features that later digital watches would include. All the Pulsar watch did was tell time. But in an age when computers were still enormous, lumbering machines, the prospect of wearing anything that could be construed as a computer on your wrist was downright science fictional. And much as today's watches tout sensors to monitor your heart rate or activity, the Pulsar boasted a light sensor that could adjust the brightness of the LEDs so that they looked the same to the eye regardless of the lighting conditions.

"That model sold for $2,100, which was more than a new Ford Pinto went for at the time," journalist Harry McCracken wrote in a retrospective on early digital watches. A Pulsar even appeared on James Bond's wrist in 1973's Live and Let Die.

But that prestige didn't last long. Technology companies soon flooded the market with new products. Back before Commodore International—the company behind the iconic Commodore 64 and Amiga computers—got into the PC business, it released its own LED watch in 1975:

Other computer companies, including HP, Intel, and Sinclar, also got in on the action. "In short, the 1970s watch business was a preview of the 1980s PC business," McCracken observes. "For the first time, a bunch of electronics companies which had previously specialized in scientific equipment and business machines started learning about selling gadgets to consumers."

Commodification doomed most of these efforts as a prices for digital watches went from thousands of dollars to just a few bucks in the late 1970s. Commodore, HP and the like soon moved on to the more lucrative and exciting PC market. But now, like the hour hand slowly ticking its way back to 12, the computer industry is returning to the watch businesses.