Paolo Amoroso's Journal


ChromeOS 104 landed on my Chromebox delivering a pleasant surprise, the ability to access serial USB devices from Android apps.

When I plugged the Z80-MBC2 Z80 homebrew computer into the Chromebox under chromeOS 104, the system popped up this notification allowing me to connect the device to Android or Linux, not just Linux as before:

chromeOS notification allowing to connect a Z80-MBC2 serial USB device to Linux or Android.

The notifcation confirms the detection of the Z80-MBC2's CP2102 chipset and says:

USB device detected

Open Settings to connect CP2102 USB to UART Bridge Controller to Linux or Android apps

Connect to Linux Connect to Android

I had long been looking forward to accessing the Z80-MBC2 from Android. I researched a great terminal emulator app, Serial USB Terminal, which can connect to serial USB devices, features basic ANSI support, and can transfer files via XMODEM. Although the app runs fine on the Chromebox, I never figured how to connect to the Z80-MBC2. It turns out it wasn't possible, until chromeOS 104.

Selecting the notification's option to connect to Android prompts to run Serial USB Terminal, optionally setting it as the default app for Android connections.

I interacted a bit with the Z80-MBC2 from the Android terminal emulator and it's usable. Here's what a CP/M 3.0 session looks like in the app in landscape tablet mode, the window layout that works best with a terminal:

Serial USB Terminal Android app running a Z80-MBC2 CP/M 3.0 session on chromeOS.

Input goes in a text field separate from the terminal output. It feels awkward on the desktop but natural on mobile devices with touch interfaces.

Serial USB Terminal's ANSI support seems limited or incomplete, but I haven't checked extensively.

I tried transferring a file via XMODEM from the terminal emulator to the Z80-MBC2 under CP/M 3.0. But, as with Crostini Linux, nothing happens and the XMODEM transfer doesn't work. More experimentation may provide clues on the XMODEM issue.

So far I haven't played with the Z80-MBC2 much from Android, but it's great to have another option for controlling the device.

#z80mbc2 #sbc #Android #chromeOS

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Back in the CP/M and MS-DOS days, developers shipped software with all sorts of device drivers to support such basic peripherals and system services as terminals, graphics cards, mices and input devices, memory management, mass storage units, printers, network equipment, and more.

Every developer pretty much had to reinvent the wheel. Yet the industry thrived, and many software houses and independent programmers published successful applications and games.

These days mobile developers gripe about Android fragmentation, a consequence of the success of open platforms like CP/M and the IBM PC.

#Android #development #retrocomputing

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Since getting a Xiaomi Redmi Watch 2 Lite smartwatch I've been monitoring the battery usage of the Mi Fitness (Xiaomi Wear) companion app for Android. On my Pixel 4 XL phone, with the watch turned off battery usage was at 10%, then dropped to an acceptable 4% a couple of days later.

I'll wear the watch mostly when on the go, so I want to control the resources the app consumes when the device is not in use.

#Android #smartwatch

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I bought a Xiaomi Redmi Watch 2 Lite smartwatch for use with my Pixel 4 XL Android phone. Here's the product packaging.

Xiaomi Redmi Watch 2 Lite product packaging

I wasn't familiar with Xiaomi's line-up of smartwatches but an Android Police article drew my attention to the Watch 2 Lite. I realized it's what I was looking for as it has the features and price point I want in a smartwatch.

Why did I get the product? Is it any good?


I loved the glanceability and essentiality of the early Android Wear. Then came apps and Android Wear — later Wear OS — smartwatches became expensive, bloated, dog slow, and clumsy smartphone replicas.

All I want in a smartwatch is a cheap device that mirrors my phone's notifications, with vibration for incoming calls as a plus. Exactly what the Android Police article advocates for, highlighting the Watch 2 Lite as an example.

Although I don't care about fitness tracking, the Xiaomi Mi Band seemed perfect. I tried a Xiaomi Mi Band 4 but returned the product, as the screen was too small and notifications were barely legible with my prescription glasses.

The 1.55” display of the Watch 2 Lite seemed large enough. At a price not much higher than the Mi Band's, I decided to give it a shot.


I've been using the Watch 2 Lite for over a day and text is comfortably legible with my glasses, particularly the text of notifications. Withouth glasses I can even read most large text. For example, the options of the system settings menu look like this.

System settings menu options on the display of a Xiaomi Redmi Watch 2 Lite smartwatch

The device is light and feels comfortable on the wrist. I don't care much for the design, which is good enough for me.

Touch sensitivity seems uneven. At times I have to tap icons or perform gestures more than once to make the actions go through.

The reviews of the Watch 2 Lite warn about the one-second delay between activating the display and it turning on, so it's something I expected. But the delay may be less of an issue than anticipated because, by the time I raise the wrist close to the eyes to view the screen after pressing a button to activate it, the display has already turned on.

It's still early to evaluate battery life. I turned off the fitness tracking features and functionality I don't need, so I expect it to be higher than average. Something to watch for is the battery usage of the Mi Fitness (Xiaomi Wear) companion app for Android, which is constantly at 10% on my Pixel 4 XL even with the smartwatch turned off.


It didn't take much to familiarize with the few features of the smartwatch. The notifications shade is just a swipe-down gesture away from the home screen.

The companion app Mi Fitness (Xiaomi Wear) is a bit confusing though, especially when signing up for a new account. But, again, exploring the app clarifies how it works.

#Android #smartwatch

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I'm among those who think the best camera is the one I carry with me.

There's no grand scheme motivating my choice not to get a traditional camera, using instead my smartphone for on the go and travel photography. It's hard to beat a compact and light device I always have handy.

In my trip to Florida to view a rocket launch from Kennedy Space Center, I took photos with my current smartphone, a Google Pixel 4 XL. Its camera recorded the two rocket launches I ended up viewing, the space facilities and museums I visited, and general travel photography.

How did the 4 XL camera fare?

Distant subjects and rocket launches

Despite having been released almost three years ago, the 4 XL still holds up well.

The camera works best when the subjects fill most of the frame. But my daylight photos at Kennedy Space Center show also good detail of distant vehicles, such as the Crew-4 Falcon 9 rocket at launch complex 39A and the SLS rocket at 39B. The photos bring out also enough detail of the daylight Starlink 4-14 launch, despite the dynamic action and the high tonal range difference between the rocket structure and the bright exhausts.

The 2X optical zoom helped make distant subjects large enough to reveal detail better. However, I wish I had a latest generation flagship device with a more powerful optical zoom to enlarge those subjects a bit more.

Night launches

Where the 4 XL camera fell short is with night photography of dynamic events.

My photos of the Crew-4 night launch didn't record much light to reveal the complex detail and delicate tones of the exhaust plume of the ascending rocket. At that point, the booster was too far and not lit enough to show any detail.

As for the launch itself, from when the rocket engines ignited to when the booster cleared the tower and began ascending, the performance of the 4 XL was similar to that of the newer generation devices the friends who traveled with me used. In my photos, the ascending rocket looks like a saturated blob of light. The tonal range was so high, with the black background of the night sky contrasting with the blinding rocket exhausts, that not even recent smartphones may adequately capture and present it.

Wide-field photography

This travel experience with the 4 XL camera made me change my mind on lenses.

I thought a wide-angle lens wouldn't be useful to me, as I don't do much landscape or people photography, and preferred a lens with optical zoom.

However, by shooting photos at Kennedy Space Center, I realized that, without a wide field of view, it's hard to frame large and close objects in full — or nearly in full — without cropping. A wide field lens would have come in handy, for example, to shoot the Atlantis Space Shuttle or the Saturn V. You can come very close to these vehicles, which is a challenging observation point for framing.

#Android #space

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For years Google encouraged Android developers to pretty please support tablet screens.

Nothing happened. Then Google repeatedly reported Chromebook shipments and Android app usage on Chrome OS were skyrocketing. Again, crickets. Google didn't lead by example either.

The carrot didn't work, so Google is going with the stick. The Play Store will change search rankings and recommendations to prioritize apps with tablet and large screen support, and warn when installing apps that don't meet these quality standards.

About damn time.


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Is usable on mobile?

Let's find out. I'm writing this with the plain text editor in Chrome on a Pixel 4 XL Android phone.

I can use nearly all the editor's features except for attaching images, which I'm not sure is possible on mobile. The distraction-free environment is clean and makes a lot of text fit on the screen.

Markdown formatting

Here's some rich text I'm typing with Markdown syntax in italics and bold. Some Python code:

def square(x):
    return x * x

A bullet list:

  • one
  • two
  • three

A numbered list:

  1. one
  2. two
  3. three

Quoted text:

This is quoted text. I wish I had some witty thought to share for the occasion.

And finally some displayed MathJax: $$y = f(x)$$


The editor is quite usable for posting text content on mobile. The only limit is how fast I can type with the on-screen keyboard.

#blogging #Android

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