15$ fitness tracker likely containing NRF51822

[54696d21]

Hi, think I found a significatantly cheaper fitness tracker likely also featuring the NRF51822. Although I found only one seller on AliExpress that mentioned that an NRF51822 is used in the article description:
here

there are several different sources that confirm it, for example: here and here. I contacted a bunch of sellers on AliExpress to ask what chip it has and I'll report back.

Another piece of evidence is that the manufacturer (I assume it is the manufacturer) has Videos on their Youtube-Channel showing how to update the firmware of the fitness tracker using the NrfConnect app: here

I ordered one for less than 15$ (12,35€) and I'll report back.

[54696d21]

here is a teardown of this particular device, it contains the 16kB version of the NRF51822 (according to the author of that thread)

[curtpw]

Looks awesome! I'd love it if additional devices were added to this project. If this interests you, a couple things we be helpful:

1. complete pinout for sensors/peripherals
2. Enough microscope/closeup pictures for users to visually track traces across the PCB
3. A variant file for Sandeep Arduino Core support or instructions for use with some other platform like ARM Mbed

[54696d21]

I definitely plan on providing images of this fitness tracker and attempting to get the other things you mentioned as well. I'm especially interested in this device as the company that distributes it shows in videos on youtube that DFU via the official Nordic App is possible, so it might make things easier at first. Also the are several firmware binaries available for this device so I should be able to flash it back after a failed attempt (without the need of flash dumps)

[utya1988]

Hi. What about dfu on iwown i5?