Hacking The 22€ BLE SR08 Smart Ring With Built-In Display

In the process of making everything ‘smart’, it would seem that rings have become the next target, and they keep getting new features. The ring that [Aaron Christophel] got his mittens on is the SR08, which appears to have been cloned by many manufacturers at this point. It’s got an OLED display, 1 MB Flash and a Renesas DA14585 powering it from a positively adorable 16 mAh LiPo battery.

The small scale makes it an absolute chore to reverse-engineer and develop with, which is why [Aaron] got the €35 DA14585 development kit from Renesas. Since this dev kit only comes with a 256 kB SPI Flash chip, he had to replace it with a 1 MB one. The reference PDFs, pinouts and custom demo firmware are provided on his GitHub account, all of which is also explained in the video.

Rather than hack the ring and destroy it like his first attempts, [Aaron] switched to using the Renesas Software Update OTA app to flash custom firmware instead. A CRC error is shown, but this can be safely ignored. The ring uses about 18 µA idle and 3 mA while driving the display, which is covered in the provided custom firmware for anyone who wants to try doing something interesting with these rings.

26 thoughts on “Hacking The 22€ BLE SR08 Smart Ring With Built-In Display

    1. I just want one that can last a few months with an LCD to show the time. Doesn’t exist.
      I have attention problems and waiting for LED displays to show the time is awful. I want to glance and go. A pair of glasses with embedded time would be amazing, without the AI and data hoovering please.

      1. I have cheap clocks scattered here, there, and everywhere around my shop, as well a couple of talking clocks that announce the time on the 1/4 hour. Of course that only helps when I’m in the shop.

    1. If you’re working at a job where, say, a ring is dangerous to wear, you probably already know this thing isn’t for you. But it might be fun/ funny to get it to work as a presence detector when pairs to apc so you’re screen doesn’t lock, like you can do with android and chrome os.

        1. Thank you for noticing.
          She
          Less funny, more trying to put some positivity and optimism in the comments.

          I seriously have been looking to get a smart ring for a few purposes but none meet my needs exactly. This project actually fixes that and might be just what I need.

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