Want to know what the weather's like on top of Mount Logan?

Chances are, nobody's going to volunteer to spend a year on Canada's highest mountain just to measure temperature, wind, and snowfall. And even if someone did volunteer, the cost would be prohibitive.

But a datalogger can do it.

Dataloggers can record streamflow under ice, the temperature of a power transformer, emissions from industrial exhaust stacks, conditions inside a sealed museum case, and myriad other things.

Over the past 25 years, dataloggers have transformed the way this sort of information is collected -- and the amount that can be collected.

So what is this amazing gadget?

"Dataloggers are nothing more than a combination of a voltmeter and a computer," says Pete Kociuba, one of the earliest users of dataloggers in Environment Canada.

"One connects instrumentation to the datalogger using standard electrical circuits, applies a voltage and measures the resulting signal."

Dataloggers can range from the size of a palmtop computer to a substantial box weighing several kilograms. The instrumentation, or sensors, attached to them might measure any of a variety of things, such as temperature, humidity, wind direction, wind speed.

Information from the sensors is fed into the datalogger as an electrical signal, and the datalogger's circuits translate it into measuring units like degrees or kilometres per hour.

The information can be printed out on the spot or transmitted to a computer over a phone line or satellite link. Some dataloggers, especially in remote locations like Mount Logan, just store the information until someone arrives with a laptop computer to download it.

Kociuba's first major experience with dataloggers was a memorable one, both for him and for Environment Canada -- the 1988 Winter Olympics in Calgary.

He was responsible for providing automated observations, the weather data that would determine if a venue was suitable for a sport or whether an event could go ahead as scheduled. At the time, dataloggers weren't widely used in Canada for climate observation.

"It was a gamble and we knew very little about them. It was the only system that could be rapidly delivered within the budget allocated," he says. "In actual fact, I planned the complete acquisition in one afternoon."

And it worked.

"I spent a lot of time in Calgary the year prior to the Olympics on all the venues," Kociuba says. "Surprisingly, I was never in Calgary during the Olympics because virtually all problems had been solved and everything worked flawlessly, at least from the data acquisition end."

There was one minor disaster, but that didn't happen until well after the Games had ended.

"The Nakiska Ridgetop station was lost after the Olympics because of strong winds. The battery was never located, the cups were gone, the station mangled," Kociuba recalls. "The last reported observation showed peak winds of 105 knots before it disappeared."

After the Olympics, all Environment Canada regions began using dataloggers on a limited basis for weather and climate data. In the early 1990s, the department developed standards to ensure the information collected by dataloggers was reliable.

"Since that time there has been a proliferation of datalogger autostations," says Kociuba. "All you need is a box and a tower, and you're off and running."

Dataloggers have spread throughout science and technology, recording a vast array of information cheaply and reliably.

In fact, the sheer amount of information can be a problem. Data still has to be analyzed in order to be useful, and it's easy to collect more than the analysts can handle.

Preserving continuity with pre-datalogger information is also important, says Kociuba.

"The real secret with dataloggers is to ensure that they are backwardly compatible with the manual readings that were taken before that."