Huawei Watch blood oxygen saturation (SpO2) measuring feature

Blood oxygen saturation (SpO2) is a feature in the latest Huawei and Honor smart watches.

Image from Huawei's website

This feature is available in the Huawei Watch GT2 sold in China, but had somehow been disabled in that model sold in the international market. Anyhow, this feature has now been enabled to Huawei Watch GT2 sold outside China as well, following its firmware update version 1.0.6.26 and above (latest firmware version as of now should be 1.0.6.32).

SpO2 represents an estimation of oxygen levels in a person’s bloodstream. According to description in Huawei's website, "blood oxygen saturation (SpO2) is one of the important vital signs that can reflect the oxygen supply of the body. Very low levels of SpO2 can result in serious symptoms such as lack of energy, fatigue and light-headedness."

Under normal conditions, a healthy person should have an SpO2 level between 90 and 100.

The heart of an average adult normally pumps about 5,000 ml of blood per minute to the tissues and organs of the body, delivering about 1,000 ml of oxygen per minute to the body. Body function will be affected if the oxygen is at low level, causing hypoxemia and even hypoxia problem.

There are 2 types of hypoxemia. Acute hypoxemia occurs over a relatively short period of time, while chronic hypoxemia is ongoing over a longer period.

Common symptoms of acute hypoxemia include: shortness of breath, rapid breathing, wheezing, cough, confusion, headache, fast heart rate, and bluish colour in skin, fingernails and/or lips.

Common symptoms of chronic hypoxemia include: pulmonary hypertension, cor pulmonale (enlargement of right-side of the heart), heart failure, and polycythemia.

People who are having a higher risk of hypoxemia should regularly check their SpO2 level. You are one of them if you are:

• always on a busy work schedule
• working or living in a stressful environment
• working in a situation that needs to use a lot of brain everyday
• located in a place of high-altitude (with low atmospheric pressure)
• elderly people (with decreased body function)
• snoring a lot or having sleep apnea problem (might cause respiratory obstruction)
• having heart defects
• having lung conditions, including asthma, emphysema, bronchitis, corona virus infection, etc.

Huawei SpO2 sensor technology makes it easy to measure SpO2 level, anytime, at any place. Clinically, SpO2 level is measured using arterial blood gas (ABG) test, pulse oximeter, etc.

To measure SpO2 with a Huawei / Honor watch or band that supports the feature, just keep your arm still, fasten the strap tightly, and make sure the screen is facing up. Then, swipe on the screen for the SpO2 function, and start your measurement. It will take about 1 minute to complete.

Using Android phone's camera as webcam for computer with DroidCam

You need a webcam in order to do video conferencing, or to do vlogging, or to perform online talks, ...

You might have a desktop computer with a monitor that without a camera (which is usually the case), or you need a better camera than the one on your laptop (which usually has a low resolution), or you need a replacement for your malfunctioned laptop camera, or for whatever reason that you need a webcam for your computer, wait a minute and read this before you go and purchase a physical webcam, because you can turn your Android phone into one.

DroidCam is a solution to let you make use of the camera on your Android phone to become the webcam of your computer running on either Windows or Linux operating system.

It has a pretty low hardware requirement, so you can easily turn your old Android phone with a functioning camera into your webcam. Of course, it is even better when you run it on Android phone with better specs.

All you need to do is download and install DroidCam Wireless Webcam by Dev47Apps from Google Play Store, and then download and install DroidCam client into your computer.

• Download webpage of DroidCam for Windows
• Download webpage of DroidCam for Linux

Beside video, DroidCam is also able to optionally stream audio from the microphone of your phone to your computer.

DroidCam can connect and stream to your computer either through WiFi, USB or HTTPS connection. WiFi is the preferred one, as it is the easiest to setup and use.

When you run the DroidCam app in your phone, you should be able to see its connection information, including the internal IP address of your handphone, and the DroidCam server port.

By default, DroidCam is using the back camera of your phone (which usually has a better spec than the front camera). You can switch it to the front camera in DroidCam setting.

If you run the DroidCam Client in your computer with the IP address and port number as shown on the DroidCam app in your phone, and click the Start button, you should be able to see the video captured by your phone's camera in DroidCam Client.

For example, before clicking the Start button in DroidCam Client, there is no webcam video shown in Skype. It will show a blue or green background.

After clicking the Start button, Skype will immediately captures the webcam video.

Note that Skype install through Microsoft Store is not working with DroidCam. If you encounter this problem, just uninstall Skype and install the Skype desktop version from the URL given below. It should work then:

• https://www.skype.com/en/get-skype/

On your DroidCam screen in your phone, you can also find 2 HTTPS links.

The first link is accessible from your web browser such as Google Chrome, and it will open up the DroidCam web client.

The second link is accessible with video streaming client, such as VLC Media Player. The setting for VLC Media Player is as below:

DroidCam has a feature to allow you to protect your HTTPS access with username and/or password.

DroidCam is free for use, with in-app ads support. You can also buy DroidCamX Wireless Webcam Pro in Google Play Store to remove the ads and to get more features.

You might probably also be interested to read about:

• Using Android phone's camera as webcam for PC and Mac with Iruin

Logitech MK220 wireless keyboard and mouse combo - work well with Raspberry Pi Zero W

The Logitech MK220 is a combo of Logitech wireless keyboard K220 and Logitech wireless mouse M150, both sharing the same USB receiver communicating using 2.4 GHz band with effective connection range of up to 10 meters or 33 feet.

The keyboard is powered by 2 AAA size batteries, while the mouse is powered by 2 AA size batteries. The batteries in the keyboard can last as long as 24 months, while the batteries in the mouse can last for about 6 months.

The keyboard is very compact in size, makes it easy to carry around and also need less space to store. Despite its compact size, it has full size keys of the same size like normal keyboards, except for the first row of function keys which are only half the size of the other keys. This keyboard is pretty quiet. It is also spill resistant.

The mouse is of the same size like other normal mice. It doesn't have fancy features, just 2 buttons and a scroll wheel.

I can't find any power on/off switch on both the keyboard and mouse. I think they are designed to be always on, and will go into standby mode when connection is not made with the USB receiver.

This Logitech MK220 is plug-and-play to Windows, Linux and Android systems. I find this combo pretty ideal to be used as input devices for Raspberry Pi.

It works flawlessly with my Raspberry Pi Zero W, by connecting its USB receiver with a micro-USB to USB converter to the Raspberry Pi's micro-USB port.