Wednesday, April 29, 2020

My Tx8 3.5mm AUX to Bluetooth 5.0 converter for audio transmitting / receiving

My Ruizu X02 MP3 player is without Bluetooth output function, and I think it would be good to add Bluetooth function to it, so that it can output audio to wireless earbuds, Bluetooth speaker, soundbar, etc.

There are cheap AUX to Bluetooth converters available, some even priced below RM20. Based on their product description and customer review, the follow shortcomings are quite common to them:

  • Single function of either Bluetooth receiving or transmitting only.
  • Poor and short distance connection.
  • Sound is lagging behind due to low transmission rate.
  • Battery only works for short hours before recharging needed.
  • Product quality not so good with high faulty rate after some times of use.
Anyhow, I managed to find this Tx8 2-in-1 Bluetooth transmitter and receiver, at the cost of below RM30, with the following features:
  • Supports Bluetooth 5.0 for better audio data transmission quality.
  • Can work for 8-12 hours before battery recharge is needed.
  • Transmission distance exceeding 33 feet.
  • Able to remember the paired devices.

It is very compact in size, easy to carry along. It even has a fixed folder design. It comes with USB charging cable, AUX cable, RCA cable, and a user manual.

I have purposely put my Logitech M590 mouse beside to give a better idea about its size.

By connecting the Tx8 with cable to the audio output of MP3 player, computer, handphone, tablet, TV, and any other devices with AUX audio output port, the Tx8 can transmit the audio wirelessly through Bluetooth connection to wireless earbuds, speaker, sound bar, Hi-Fi system, car audio system, etc.

On the other hand, by connecting the Tx8 with cable to the audio input of a speaker, radio, sound bar, and any other audio devices with AUX or RCA input, the Tx8 can receive the audio wirelessly through Bluetooth connection from handphone, tablet, computer, TV, media player, smart watch, etc.

The Bluetooth pairing is pretty fast, and the connection is pretty stable.

If you are looking for similar gadget with an affordable price, you can consider this one.

Saturday, April 18, 2020

Raspberry Pi - fully working computer at the cost of RM300++ (best for home use during and beyond MCO period)

During current Movement Control Order (MCO) period, there are quite a lot of schools have resorted into online teaching and learning mechanism. There are also quite a lot of companies practicing work-from-home (WFH) concept.

However, this raised a question: what if the family does not have a computer at home? And, what if the family only has one computer at home, but needs to be shared by parents who need to WFH and also multiple children who need to learn from home?

Well, you can buy a fully working computer online, including additional computers needed for all your family members, at the cost of RM300++ each, in the condition that you have a screen (either computer monitor or TV) at home, and Internet access (either phone's hotspot sharing or broadband Internet).

The full set Raspberry Pi (recommended for Version 4 model B with 2GB RAM) with all its required accessories, is a fully working computer at the cost of about RM300-RM360 only. Beside its low cost, it also consumes minimal amount of electricity and requires minimal storage space due to its small size.

It is good enough for normal online learning, doing assignments with office suite (word processor, spreadsheet, presentation slides, database, etc.), and some entertainment including games.

With about RM360, you can buy the following full set of computer:
  • Raspberry Pi 4 Model B with Quad core CPU and 2GB RAM - RM174
  • Casing for the Raspberry Pi 4 Model B - RM25  (*1)
  • Official Raspberry 15W power adapter - RM35
  • Micro-HDMI to HDMI cable - RM10
  • Wired earphone - RM15 (*2)
  • 16GB micro SD card preinstalled with NOOBS - RM36 (*3)
  • Logitech MK220 wireless keyboard & mouse - RM65 (*4)

*1: The casing is an optional item. Without the casing, the Raspberry Pi will be a naked computer board as shown in the image above. With the casing, it will look like below:

*2: If you connect the Raspberry Pi to your TV using HDMI cable, you can make use of the audio output from your TV. You need an earphone or speaker, either wired or Bluetooth, to listen to the audio from Raspberry Pi if you are using a monitor without audio output.

*3: Raspberry Pi makes use of micro SD card as its "harddisk". You can also buy a blank micro SD card, which is much cheaper, and download NOOBS for free from Raspberry's website. That will require some basic computer knowledge to download and install NOOBS into the micro SD card. NOOBS is an installer that will prepare the SD card for Raspbian (including partitioning, etc.), and automatically download and install the operating system into it.

*4: Alternatively, you can also use cheaper USB wired keyboard & mouse to further reduce the cost.

The recommended operating system will be Raspbian, a scaled down version of Debian Linux. It has fully functioning Chromium or Vivaldi web browser, LibreOffice resembling the Microsoft Office, and tonnes of installable free softwares in Raspbian repository. This is good enough to access to Google suite of applications (Gmail, Google Drive, Google Docs, Hangout, ...), watch online & offline video, listen to online & offline music, access to learning portal and other websites, attending audio/video conferencing, etc.

There are also programming tools and graphic design software available in Raspbian for learning purpose.

In fact, you can install a full LAMP stack in Raspbian and turn your Raspberry Pi into a web application server as well.

The Raspberry Pi 4 Model B also supports webcam and voice input with additional module, which will need additional cost to buy and some technical skill to assemble.

Beside Raspbian, there are other choices of operating system that works with Raspberry Pi too, including Microsoft Windows 10 IoT Edition, which you can explore if you are enthusiastic with them.

Thursday, April 16, 2020

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 and above (latest firmware version as of now should be

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.

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