Coding Time

We have all been tempted at one time or another by the ultra-cheap electronics, usually manufactured in China, that are available on sites like AliExpress. The prices are often so low that the deals seem too good to be true. As YouTuber Poking Technology recently found out, sometimes the deals are in fact too good to be true. Yet even still, if you are willing to put in some work and accept the shortcomings, the devices may actually be worth picking up anyway.

Poking Technology bought a smartwatch for about three dollars. The shiny screen and slick design makes these things look very appealing, especially considering the low price. But when tested, it was found that in reality the functionality was seriously lacking, the battery life was terrible, and the user interface was a nightmare. Worse yet, the few sensors that were available seemed to be fake. The step counter added hundreds of steps while sitting on a desk, and the heart rate/blood pressure sensor always seemed to give about the same measurements.

You get what you pay for, it seems. Poking Technology decided to do a teardown to see exactly what was going on with this smartwatch. It turned out that the so-called heart rate sensor was just an LED, and the spot for the actual chip was unpopulated on the PCB. The spot for the accelerometer that would power the step counter was similarly unpopulated. About all that was real was a Telink TLSR8232 microcontroller, the display, and a vibration motor.

That is not a lot, but yet given the form factor, it is something one can work with. Poking Technology thought that if this thing ran MicroPython, the terrible interface could be removed, and a user could program it to do something that is actually useful. It may not be anything revolutionary, but for 3 bucks or so, it would be a steal.

After going through a long and painful process of attaching the internal components of the watch to a custom breakout board, then dumping and writing the flash with a custom Raspberry Pi Pico-based debug interface, Poking Technology was most of the way there. But to develop new firmware for the onboard Telink microcontroller, a good deal of work was still needed.

The microcontroller did not contain an Arm CPU core, as you would probably expect, but some strange, proprietary processor instead. And that meant a development toolchain specific to this microcontroller had to be installed and learned before going any further. After slogging through that work, the job of porting MicroPython turned out to be pretty easy. Within an hour an initial version was up and running, but of course there was more work to follow to smooth out some rough edges. When all was said and done, MicroPython worked fine with the 16 kilobytes of RAM and unusual architecture of the Telink chip.

While the watch only cost a few dollars, the engineering effort was probably worth thousands, so was it worth it? Well, not for Poking Technology, unless you count it as an educational exercise. But for those of us that can just borrow that work and have a MicroPython watch in no time, the 3 dollars is well worth it. Take a look at the full video for an in-depth teardown of this junky and fake, yet still cool in some ways, smartwatch.