via HACKADAY: Tech in Plain Sight: Glucose Meters

If you or someone you know is diabetic, it is a good bet that a glucose meter is a regular fixture in your life. They are cheap and plentiful, but they are actually reasonably high tech — well, at least parts of them are.

The meters themselves don’t seem like much, but that’s misleading. A battery, a few parts, a display, and enough of a controller to do things like remember readings appears to cover it all. You wouldn’t be surprised, of course, that you can get the whole affair “on a chip.” But it turns out, the real magic is in the test strip and getting a good reading from a strip requires more metrology than you would think. A common meter requires a precise current measurement down to 10nA. The reading has to be adjusted for temperature, too. The device is surprisingly complex for something that looks like a near-disposable piece of consumer gear.

Of course, there are announcements all the time about new technology that won’t require a needle stick. So far, none of those have really caught on for one reason or another, but that, of course, could change. GlucoWatch G2, for example, was a watch that could read blood glucose, but — apparently — was unable to cope with perspiration.

Even the meters that continuously monitor still work in more or less the same way as the cheap meters. As Hackaday’s Dan Maloney detailed a few years back, continuous glucose monitors leave a tiny sensor under your skin and measure fluid in your body, not necessarily blood. But the way the sensor works is usually the same.