Bangle.js v2 - Hackable Javascript Smart Watch (ADA5427)

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Bangle.js 2 is an open, hackable smartwatch. With a sunlight-readable always-on screen, 4-week battery life, complete flexibility, and complete control of…

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I went to install my first app, but it said there was a firmware update available.
I installed that, but it appears to have failed and is not in an endless DFU loop. I’ve tried everything I can find on the web, including the nRF apps on ios and android.

The fix was to use the DFU Firmware Update app. I set the packet count to 1, so it wouldn’t break up to multiple packets & it worked. That took 57 million attempts and variations to discover.

But it’s working now for anyone else facing the same issue


Hi Cheese,

Many thanks for sharing, I am sure your fellow makers are absolutely going to appreciate this.


Bangle.js 2 is a refreshing break from expensive smart watches

By costing as much as the more expensive ones?

I’m kind of tempted to try one of those ones I can get for close to ten bucks… It’d be a no-brainer if I knew I could flash a custom ROM.

Although what would be a refreshing change from every other smartwatch is a thickness of 6mm or less. This one is double that, like most of them…

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Hi Kimmo,

I see what you mean about the price point compared to some cheaper watches available, though I believe in this page its referring to significantly more expensive digital watches such as those sold by Apple, Samsung and more high end tech companies which have capabilities similar to a smartphone.

In comparison to those watches, this product can be programmed to behave in a similar way to those at a significant price reduction.

Nevertheless if you do end up getting a cheap watch and programming it yourself, it would be great if you could put up a post about it, as I think everyone would be very interested to see how it goes.


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I have a cheap smartwatch on the way from Temu: it was like 22 bucks. You can find them for as low as $7!

But as for something a bit more decent, I realised I had a unicorn sitting in a drawer… A Casino DBX-100 from 1988, the only Data Bank Casio they ever made with a full dot matrix screen. Unfortunately the alphanumeric button pad on the front of them was made of stuff that didn’t survive the years, so I’ve bought a dead example of a later model with a more durable button pad… Gonna be quite the challenge to transplant it.


Hi Kimmo,

That is a beast of a watch. Good luck on the transplant, I am sure that every time you check the time on that you will be reminded of how rewarding it was fixing it.


Actually there were a couple of other Casios with dot matrix screens, now that I’ve been down that rabbit hole…

Here’s the current state of my DBX-100:

Oh yeah, the Temu smartwatch turned up; it was actually less than nine bucks. It is of course, janky AF. Still pretty awesome for the price, though… But as long as smartwatches have to be this thick, I’m just not interested. This one is relatively good at 12.3mm…

Properly thin watches are far too rare, and stupidly underrated. The Casio is 7.5mm; pretty stoked with it. Looking forward to this parts watch turning up around the end of January; it was like 30c postage from India…


Hi Kimmo,

That’s pretty impressive price hunting. Let us know how you go reprograming the Temu watch.

If you had the time, maybe you could create a sperate topic on your Casio watch project. I think everyone is very excited to see how it goes.



Cool, will do. It’ll be a while; the donor watch is supposed to take until the end of January to arrive :unamused:


So the watch turned up yesterday, actually… Complete with leaked battery inside. Fully disassembled and cleaned it up with CRC and brake cleaner, but it was cactus.

Which I pretty much expected, but thought I better check before I destroyed the watch… Rather than risk damaging the button pad by digging past the lip around it and peeling it off, I just cut and belt-sanded most of the case away until I could peel what remained of it from the button pad. That much seemed to be a success…

But it turns out the pitch of the eight contacts coming off the pad is slightly different, such that the outside two don’t stand a chance of contacting. Also, when I hold it up to the light, it looks like the tracks on the film are interrupted by gaps anyway. I have some conductive paint somewhere, I guess that’s my only hope.

(I’ll get around to posting a thread when I’ve taken some pics; currently at work)


Might have to revise that…

I had a play with it, and then forgot about it for a couple of weeks after it became apparent there was basically zero customisation possible… Maybe there’s some way to wirelessly flash it, but the USB plug which is exposed when you pull off one half of the band only has power pins.

Anyway, after it sat on my bedside table for a couple of weeks, it won’t take a charge, or at least it won’t power up after charging… I didn’t check to see if it drew any current when I first plugged it in, but there’s certainly zero amps going into it now, and it’s dead.

Which I suppose is kind of okay anyway, since I mostly bought it to attack it with a Dremel to see if I could repurpose any or all of its guts… That will probably be tricky though.

The only obvious point of entry is perhaps prising off the screen, which is a continuous bit of plastic running from top to bottom, but that includes the touch interface which probably wouldn’t survive that. The next most promising avenue of attack is probably just cutting around the edge across its widest axis, or maybe carving the back off from around the pulse sensor…

With a bit of luck it won’t just be fully potted with the material they’ve used to mold the case, and there’ll be some sort of halfway obvious programming interface… And there’ll be someone out there who has or will have some sort of help for me in some form, since I’m no Bunnie Huang.

If the unit inside is relatively retrievable and repurposeable, these things could still be great value for tinkerers…

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Appreciate the time you’re taking to document your travels @Kimmo :slight_smile: I’m sure whoever treads this ground after you will find it most helpful. I’ve done a little research and found the bangle app library where it looks like ‘hackable’ means you can write and deploy your own apps. Nothing mentioned yet about how hardware hackable this device is though…

Who doesn’t wish they had these super powers :sweat_smile:

That sucks to hear :frowning: I’m sure this is a pretty low turnover product which probably contributed to being DOA. It’s fortunate in this case that you had other plans.


Got my fingers crossed pretty hard the NOS DBX-100 is still good… Should find out this week :crossed_fingers::crossed_fingers:

The cheapo smartband is basically a black box until some whiz reverse engineers it. If I use it, the app it’s tethered to is probably broadcasting my SMSes in plain text while it mines Bitcoins…

Now with added thinness… 9.3mm

How have I gone most of my life without a hot glue gun. The wasted years

Hell yeah. Looks expensive