Remotely sensing soldiers' distress.

• Author: Jean, Grace
• Position: INSIDE Science AND Technology

* In the medical realm, offering treatment to a patient who has suffered serious trauma within the first 60 minutes of injury greatly boosts the chance of survival.

This "golden hour" also exists on the battlefield, where advancements in medical techniques have helped to preserve the lives of thousands of troops when precious minutes can demarcate the difference between life and death.

But to gain a lead on the fragile hourglass of medical intervention for war-related ailments and injuries, militaries have been searching for technologies that can remotely monitor the welfare of an individual on the battleground and alert unit commanders and medical personnel of problems.

Until recently, such devices were prohibitively bulky and expensive, consumed power rapidly and had meager transmission capabilities.

But with the advent of personal handheld electronics and the miniaturization of components, the ability to package such sensors inside palm-sized devices has allowed remote welfare monitoring systems to become feasible in war zones.

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Hidalgo, Ltd. based in Cambridgeshire, England, has developed a small sensor that monitors a person's cardio-respiratory welfare and temperature, among other vital signs. The device also gauges how a person is positioned, whether standing or supine. Algorithms then calculate the person's well-being using the data, says Justin Pisani, technical director.

"That's quite powerful, being able to remotely know whether the 10 men you have lined up are actually moving, and to a degree, what sort of activity they're engaged in," he says.

Worn on the sternum, the device, called Equivital, contains a low-power mobile computer, amplified circuits and accelerometers. It has a number of electrical interfaces that connect through a sensor to the body.

"Basically you're wearing a belt that has some intelligent areas woven into it, where it can sense parts of the body, and it can pass small electrical currents off the body through into the sensor," says Pisani. The computer turns those electrical currents into digital data, and using some miniature accelerometer techniques originally developed for measuring movement in robots, the sensor can determine whether someone just stood up, or is lying down.

It sends out a "traffic-light" output that can be displayed as icons on a digital map, much as friendly or enemy forces are represented on blue force tracking systems. An icon that is green means an individual is...