Did I break my Bangle.js 2?

[plastbox]

Hello!

TL;DR The touchscreen input of my Bangle.js 2 has died, and the battery drains in a day, down from about a week. Likely following a sleep-addled attempt at connecting it to the wrong magnetic charger (details below), or as a delayed result of plugging it into my computer's USB port.

Years back my Pebble died, leaving me frustrated at the lack of hackable watches with a Sun-readable always-on display. See, I have diabetes and I use a CGM, and having my current and recent blood glucose levels always available like that is amazing. So I was very happy when I stumbled on the Bangle.js 2. Bought it, and have been a happy user since.

Until at some point this summer it's touch screen simply stopped working. I've restarted it, I've left it to discharge fully —which I should note takes less than a day now whereas before it would last almost a week between charges. No change.

I've not put the Bangle through anything out of the ordinary. I don't wear it when I shower or go swimming, and the summer here in Norway has been anything but wet.

The only two things I can think of are:

• I removed the covering on the two centre pads in order to see what the Bangle would identify as when plugged into a USB host¹. I did use the watch as normal for several days after this happened though, so I don't consider it a super likely candidate.
• Waking up in the middle of the night, my sleep-addled brain managed to try and connect the charger of my BlueJay watch². This charger is also USB and has magnets, but only has two pins spaced about the same distance apart as each of the neighbouring pads on my Bangle.js 2.

So, I've likely connected 5VCD across each of the Bangle's outer pins and the data pin next to it (GND and SWDCLK, and VCC and SWDIO). Not sure what the polarity would have been, but I could find out if there is any chance this could kill the touchscreen and somehow make the battery drain much faster.

¹Turns out, nothing. The documentation is clear that these are SWDIO/SWDCLK, not USB, so impatience and curiosity got the better of me, although I have a strong aversion to stuffing the wrong signals into any cable. To the creator: Awesome job in general! But USB is USB, and standards are standards. Do better next time and I'll absolutely be buying the Bangle.js 3 <3)

²I use the BlueJay when I go swimming as it is waterproof and can gather data (using xDrip Core) from my blood glucose sensor separate from my phone.

[gfwilliams]

Hi, I'm sorry to hear this...

So the BlueJay charger was attached a few days after you peeled the label off the middle pins? That's pretty unfortunate.

Having 5v put across the SWD pins (possibly even backwards) would almost certainly cause that kind of problem. It's likely the touchscreen controller got over or reverse-volted and blew up. When you connect with the Web IDE, do you see any messages like I2C Arbitration Error when you unlock, touch the screen or reload apps?

You could also try reset() followed by Bangle.showTestScreen() and see if everything else works, or if it's just the touchscreen? We do sell replacement touchscreens, but it is possible that it's not working because the processor itself is broken.

All I can suggest is to let it run down (which you've done) and leave it for a few days. Sounds stupid, but I did some testing a while back applying voltages to those pins, and at least when it was done for short periods, the test Bangle appeared broken but came back to life a day later. Adding voltages for longer periods completely broke it though.

The pins on the middle being SWD is tricky. One thing that makes the Bangle attractive is that you can attach a debugger there if you want to and do all kinds of stuff without risking bricking it. USB data voltages are 0-3.3v so don't cause a problem on those pins if connected, but we do cover them up and advise users keep them covered too. So it's really only an issue if you take the tape off and then apply 5v in places it shouldn't be... I wouldn't expose them again on a Bangle.js 3, but unfortunately with Bangle.js 2 we were using a watch that had already been designed.

If you do want a replacement, I'm happy to provide one half price though.

[plastbox]

(edit: moved my comment into a direct reply to yours)

Thanks for taking the time to type up a great answer!

For the sake of clarity, the pin spacing and magnets of the BlueJay charger means I've connected it between GND and SWDCLK, and VCC and SWDIO, separately. Never across the two middle pins.

The terminal does indeed log the I2C Arbitration Error message. =/

If you do want a replacement, I'm happy to provide one half price though.

Wait.. are we talking watch, or touchscreen? 'cause if you're talking watch —despite my watch clearly being a victim of my own curiosity, then just tell how to get the money to you ASAP, and sign me up for whatever pre-preorder mailing list you have for the Bangle.js 3 o.O

[gfwilliams]

Wait.. are we talking watch, or touchscreen?

The entire watch. I don't want to make money of others' misfortune, so generally I say that if someone's Bangle got broken (even outside of warranty) I'll offer a new one at half price. That way I'm not really losing money, and you still get to use a Bangle without it being too expensive.

I've just sent an email to your GitHub email address (but it's at hotmail?)

[plastbox]

Email received, order sent. Thanks for the great customer experience! It's leaving me quite motivated to finish support for generic actionable notifications in Gadgetbridge and the notifications on the Bangle, and to continue exploring improvements to perceived interactivity on the Bangle (small stuff, like allowing more visual queues like outline/highlight an icon or menu item as soon as you touch it).

Have a great day!

[gfwilliams]

Great! Thanks! And yes, work on Gadgetbridge or Bangle.js would be awesome.

As you say, things like making a menu item highlight when tapped could make a big difference to how quick Bangle.js seems, and would be a great addition!