Apple Watch For Dummies. Marc Saltzman

a shutter button, the watch face will flash white, and the image will appear wirelessly in your iPhone’s photo gallery. You may need to first enable screenshots by opening the Apple Watch app on an iPhone, and then tapping My Watch ⇒ General ⇒ Enable Screenshots.

      Accelerometer, gyroscope, barometric altimeter, compass

As with other smartwatches and activity bands on the market, Apple Watch has an accelerometer that measures movement — whether you’re lifting the watch to your face to turn on the screen, lowering your wrist to not accept a call, or calculating fitness activities, including your steps taken (like a 21st-century pedometer), total distance traveled, time spent exercising, and estimated calories burned. Beginning with Apple Watch Series 3 (2017), the watch also has an integrated barometric altimeter for measuring elevation — like counting the steps you climb or descend — as well as calculating altitude, for those who ski, hike, or mountain climb!

      Beginning with Apple Watch Series 6, it’s now an “always-on” altimeter for all-day real-time elevation data captured on your wrist.

      With the Apple Watch’s accelerometer and gyroscope sensor, Apple Watch Series 4 (2018), Apple Watch Series 5 (2019), Apple Watch Series 6 (2020), and Apple Watch SE (2020) all can detect if you’ve fallen, and you can initiate a call to emergency services (or dismiss the alert). If you’re unresponsive after 60 seconds, Apple Watch automatically places the emergency call and sends a message with your location to your emergency contacts.

      A compass has been added to Apple Watch Series 5 and Series 6, which always points you north inside of apps like Maps, plus there’s a dedicated Compass app, too. (Cue the song “Go West” by the Pet Shop Boys or the Village People before that!)

      Heart rate sensor

      A custom heart rate sensor included with Apple Watch helps you in two ways.

       Gauging your exercise intensity and tracking overall calorie burn: (This is an estimation based on info you first input, required only once, such as your height, weight, gender, and age.) Apple Watch listens to your heart’s beats per minute (BPM) and shows you data on the screen — if and when you call for it.

       Tracking your heart rate throughout the day: Apple Watch can alert you if it detects unusually high or low heart rates — and yes, you can set the parameters if you want, even if you don’t feel symptoms. Behind the watch are multiple sensors that measure your pulse through your skin. Going beyond fitness are the fun applications too, such as sharing your heartbeat with someone — felt on his or her Apple Watch — to show you’re thinking about that person. See Chapter 5 for how to share this information to your heart’s content.

      Electrocardiogram (ECG)

      Apple Watch Series 4, Apple Watch Series 5, and Apple Watch Series 6 models all include an electrical heart rate sensor that can take an electrocardiogram (ECG) using an ECG app; the built-in sensor and the electrodes are included in the Digital Crown button. You take an ECG reading by placing a finger on the Digital Crown while wearing Apple Watch and the reading is completed within just 30 seconds. The ECG app tracks whether your heart is beating in a regular pattern or if you have signs of atrial fibrillation, a clear indicator of serious health problems.

      Blood O2 monitor (pulse oximeter)

      Beginning with Apple Watch Series 6, your wearable device is capable of detecting blood oxygen levels. When initiated by the user by tapping the Apple Watch app, green, red, and infrared LEDs shine light into your wrist, and photodiodes measure the amount of light reflected back. Advanced algorithms then calculate the color of your blood, which indicates the amount of oxygen present. Wow. Blood oxygen levels between 95 and 100 percent are considered healthy — a lower percentage could indicate compromised heart, lungs, or brain functionality — but be sure to consult with your doctor. In fact, Apple stresses the Blood Oxygen app is not intended for medical use, but rather, designed for general fitness and wellness purposes.

      Ambient light sensor

      Finally, Apple Watch has an ambient light sensor under the glass, which samples the environmental light falling on the screen and then automatically adjusts the brightness up or down to improve viewing comfort (so it’s not too dim or too bright, based on where you are). An ambient light sensor also helps to regulate the power that the display uses, thus squeezing more battery life out of the watch.

      In fact, with Apple Watch Series 5, the Retina screen is always on — just dimmed — until you turn it towards your face to read the time or other info. In previous Apple Watch models, the screen goes to black when you’re not looking at it, and takes a split second to wake up and turn on when you turn it towards you.

Tapping with Apple Watch’s Haptic Feedback

      You can tap Apple Watch’s screen, but guess what? It can tap you, too.

As with video game controllers that vibrate (when your soldier gets shot) or some smartphones and tablets (that buzz slightly when you tap a letter on the virtual keyboard), Apple Watch employs haptic technology to apply light force to your skin about relevant information.

      Apple calls it Taptic Engine, a linear actuator inside the watch that produces discreet haptic feedback.

      Consider this slight vibration a third sense (touch), along with sight and sound, to give you information. The physical sensation of a tap tells you something, such as a warning that an important meeting is about to start without you even having to look down at your wrist. It can also be a silent alarm clock to wake you up in the morning instead of bothering your significant other. Or it can transmit the feeling of your loved one’s heartbeat even though he or she may be miles way.

      What’s more, Apple Watch can tap different patterns based on who’s reaching out to you (such as two taps for your spouse and three taps for your boss), or perhaps the haptic pattern tells you what the information is (one tap for the time on the hour, four taps for a calendar appointment, and so on). Neat, huh?

      In the near future, Apple Watch’s haptic feedback may let you know about important health information — perhaps when working in conjunction with sensors. Imagine if someone living with diabetes could feel a haptic tap on the skin to tell him or her it’s time to take insulin based on the body’s blood sugar levels.