Fixing a Smart Ring with Dumb Software
Hacker Aaron Christophel is back at it, unlocking the hidden potential of a $20 smart ring with custom firmware. But is the hassle worth it?
Scanning the websites of certain overseas electronics retailers can turn up some deals that are so good that they often seem too good to be true. And well, sometimes they are. It is not unheard of for smart rings to have fake biosensing capabilities, for example. But by and large, the devices are as described — just with a lot of shortcuts that were taken to get the prices down. One of the main areas where costs are cut is in firmware development. This means you might get perfectly fine hardware that has been handicapped by poorly written software.
Aaron Christophel has become something of a connoisseur of dirt-cheap consumer electronics, but he does not simply settle for junky interfaces. Rather, he tears the devices down to understand them, then figures out how to flash them with custom firmware to make the most of the hardware. Previously we have seen a smart ring, imitation Apple AirTag, and a cheap e-paper display among Christophel’s finds.
Recently Christophel took a look at another smart ring of questionable origin, but this time with an interesting difference — it sports a tiny display. It also has an accelerometer, Bluetooth Low Energy connectivity, and a Dialog DA14584 microcontroller with a megabyte in external flash memory, making it a nice platform for hacking. But as might be expected, the firmware was sorely lacking.
To make the platform more useful, Christophel tore down a number of these rings to see what makes them tick. In the process, he broke most of them and was not able to access the debugging interface, but he still found a solution for loading custom firmware.
Developing on the ring itself proved to be too difficult, so a Dialog Semiconductor development board was used instead as the development platform. This first had to be upgraded with a one megabyte SPI flash chip to match the ring’s capacity, then new firmware was developed to demonstrate a few of the device’s capabilities.
Flashing the firmware was actually quite easy. It can be done over the air with the Renesas smartphone app called SUOTA. It was just a matter of connecting to the device, selecting a new firmware binary, then letting the app do the rest.
This ring only costs about $20, which is quite good considering the hardware that is packed inside and the slick design. But make sure you count all the costs — Christophel considers the development process so cumbersome that he is setting the ring aside for now, hoping that others will continue the work and develop some useful firmware for it. What do you think? Is it worth spending weeks hacking away at a cheap smart ring, or would you rather spend a bit more and have it work right out of the box?