How the Basis Activity and Sleep Tracker Works

Lauren Vogelbaum

Basis Science

I genuinely enjoy working out - about as much as I genuinely enjoy melting into a couch with a goofy sci-fi series and a bowl of mac & cheese. But the creative and technical minds behind fitness trackers have started coming through for folks like me who could use a technological boost to their exercise regimen, but who don't have the time or motivation to analyze their biometrics down to the microsecond.

One resulting gadget is Basis Science's B1 band, which is more of a life tracker than a fitness tracker. Designed to be worn day and night, the B1 band has four sensors to measure your movement and physical intensity during exercise, down time and sleep. Once it's got those measurements, Basis uses number-crunching software to (hopefully) help you not just meet fitness goals but create new habits.

Those four sensors start with two fairly common ones: The first is an accelerometer, which is a motion sensor that measures changes in velocity and direction, thus measuring your steps. (Learn more about how accelerometers work.) Next up is a piece of optical tech called a photoplethysmograph (PPG), which has become the standard in noninvasive heart rate monitoring. PPGs bounce light - in this case, from an LED - through your skin and back to a sensor to measure the volume of blood moving through your capillaries. (Blood absorbs more light than its surrounding tissue, so the less light comes back to the sensor, the greater the volume it records.) This volume pulses with each heartbeat, so by tracking those pulses, a PPG tracks your heart rate at rest and during exercise.

The other two gadgets in the B1 band look for indicators of exertion to give you a honed concept of how hard you're working (or resting). There's a galvanic skin response sensor that tracks your perspiration by measuring the conductivity of your skin - more sweat equals better conductivity. There are also two thermometers, one to track your body temperature and one to measure the ambient temperature around you. Both more sweat and a higher body temperature mean you're working harder.

When you use a USB cable to plug your B1 band into a Mac, PC, Windows tablet or iPad, you can pull the data from those four sensors onto Basis' desktop or web app for analysis. (This is also how you charge the device.) There, you can set goals for yourself: for example, simply wearing the B1 more often, getting more sleep, taking more breaks from sitting, or exerting yourself more during workouts. Basis will track your progress, giving you an overview of how you're doing day by day and in the long term.

According to MedCity News, Basis Science is currently working on filling backorders on the B1 band, releasing an API, and creating version 2.0 of the band, which will feature an additional sensor and a smaller, sleeker design. Additionally, an Android app to sync with the B1 via Bluetooth 2.1 may drop any day now - keep an eye on the app market. My fellow iPhone users may have to wait a while longer for an iOS version, but Basis says it's in the making.

The B1 band is retailing for $199, which is a bit pricier than many other trackers. Check out some of the in-depth reviews available around the Interwebs (I found the ones from PopSci and The Verge particularly helpful) to see whether it might be right for you - or for a fellow scifi/mac & cheese fan you know. And for lots more technical detail, check out HowStuffWorks' full article on how the Basis B1 band works.