When we talk about activity monitoring devices, smartwatches, smart clothes or any other wearable gadget, in general, there are some technical terms that may not be part of the daily lives of many of our users. Therefore, in this article, we will present the most common terms and their meaning. What does «quantified sefl» mean? Tizen? Android Wear? Discover these concepts and more.
Note: if you want to find a specific term quickly, do a search on the page using the Ctrl + F keys in Windows; or Command + F on the Mac.
Accelerometer
This is a sensor that measures linear acceleration in three dimensions, and therefore can detect the movement of an object. Specifically, an accelerometer does not detect a position, but the acceleration of one of the three axes X, Y, Z. In addition to acceleration, the sensor can measure changes in speed and changes in position.
Android Wear
Android Wear is Google’s mobile operating system for wearables. Today it is present in most smartwatches launched by manufacturers. We tested the latest version of the platform and you can check the main resources at the link below:

With Android Wear 2.0 you can install apps directly from the Play Store / © NextPit
Step counter or pedometer
This is a step count sensor and is capable of measuring the distance covered on foot. It is generally used for sports.
Gyroscope
This is a sensor for measuring orientation. Thanks to this sensor, the device can measure changes in route orientation or changes in speed.
GPS
The GPS or Global Positioning System is a sensor that can be located using several satellites in space.
Activity Monitor
Also known as fitness bracelets, activity sensors, activity monitors and fitness tracker, these are small devices that equip smartwaches, for example, and are responsible for collecting information about how much we move throughout the day. Depending on the type of sensor they offer, the price can vary widely.

This is an activity monitor / © NextPit
Sleep Monitor
A sleep monitor is a device that analyzes sleep (time, quality and consistency). To do this, it usually uses a combination of sensors (accelerometer, heart rate monitor and gyroscope) to evaluate it. In most wearables on the market, the monitor can review two fundamental elements: sleep duration and sleep quality.
NFC
The NFC, whose full name is «Near Field communiation» or Communication by Proximity Field, is a chip capable of exchanging data with another chip of the same type through waves when approaching one device to another. This technology is mainly used to validate public transport or flight cards, but also to be able to validate credit card payments, for example.
Quantified Self
«Quantified Self», usually translated to «quantified» in Portuguese, is the practice that, with the help of connected objects, allows a person to measure his physiological variables, mainly related to nutrition, physical activity or sleep. For example, these objects can be a smartwatch, a pedometer or, of course, a smartphone.
Optical heart rate sensors
Optical sensors are used to determine heart rate in real time. It consists of two elements: a light source and a light sensor. By analyzing changes in light (changes in blood flow pressure alter light), the sensor is able to determine heart rate. At the moment, however, the results offered are not very reliable.

Optical sensors work thanks to their light emission / © NextPit
SpO2
SpO2 is the saturation of capillary peripheral oxygen. This term is normally used by doctors, and it determines the amount of oxygen in the blood, that is, the percentage of oxygenated hemoglobin (containing oxygen) to the total amount of hemoglobin in the blood.
In some wearables, such as those from the company WiThings, this SpO2 can be measured by pulse oximetry. As a heart rate sensor, the analysis of the variations of a light wave is made, and the touch of the finger will give the measurement of SpO2, since the degree of oxygen saturation can change the color of the blood.
Tizen
This is the operating system designed by Samsung. Available on some smartphones and televisions, it is also present mainly in the line of smartwatches of the South Korean manufacturer.

Gear S3 / © NextPit
There are more terms out there that can be part of this glossary of terms on wearable devices. Therefore, I invite you to contribute to our team, leaving a comment in this article with some term related to the universe of wearables and that you do not understand the meaning.