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Ask HN: A cheap smartwatch with a supported SDK

52 points| 41209 | 4 years ago | reply

Hi HN, I'd love to buy a smart watch for 50$ or less that'll allow me to develop my own apps.

Looks like Google is coming out with Wear OS 3 soon, so I don't want to invest any real money in a Watch until then

45 comments

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[+] denysvitali|4 years ago|reply
Depending on what you mean by "smart watch": you can try the Pine Time: https://www.pine64.org/pinetime/

51 USD will get you a sealed smart watch and a dev kit :)

[+] 41209|4 years ago|reply
Actually this isn't a bad idea, anyway to save on shipping or get a promo code.

Once it's shipped, it's 60$ or so venturing close to what a WearOS watch cost ( I'm seeing older ones at 80$ or so)

[+] TrianguloY|4 years ago|reply
It doesn't seem to have always-on display :(

I also want to find a good smartwatch, tired of waiting for wear3.0, but an always-on display is a must have for me.

[+] 41209|4 years ago|reply
Can I write my own apps for the sealed version?

The dev kit seems a bit too low level for me

[+] azdle|4 years ago|reply
The Bangle.js 2 just delivered to kickstarter backers: https://www.kickstarter.com/projects/gfw/banglejs-2-the-open...

AFAICT, it's fully open source software (except, presumably, the nordic hal stuff?), with a JS SDK and a hosted IDE. But, I haven't used it yet because it requires WebBluetooth, and I refuse to use chrome, and I haven't figured out if the rasppi hosted IDE is still supported or not, it seems that the `nw` package doesn't support arm (anymore?).

But this was the best option I found when I was looking awhile ago.

The other things I considered were the Pinetime (software is still a bit too early from what I've seen) and "Paul's Open-Smartwatch" https://open-smartwatch.github.io/, but I really wanted GPS and that version's design isn't finished yet.

[+] simonvc|4 years ago|reply
Upvote for BangleJS2. Been wearing mine for a couple of weeks now and it's great. The always on transreflective screen is really easy to read in sunlight and the battery seems great (over a week). Being able to quickly hack watch faces using the online IDE is great, i've hacked mine to be easy to read when i'm usually asleep and only care about the time, not the date and other stuff.
[+] psytrx|4 years ago|reply
I'm wearing mine for a few weeks now, but it's been rather unstable for me. BTLE disconnects are common, and I'm not sure what the source of the problem might be. Also, it sometimes freezes in an infinite loop and drains battery really quickly when that happens.

These are all problems fixable with software updates, and it's very early stages of the project. The app store grew from 80 to 130 apps in the last 3 weeks.

The hardware on the other hand is great. It doesn't feel cheap, but it's really lightweight, which I enjoy. The e-ink display is crisp and clear, easily readable in direct sunlight, and it has 8 colors, which is a cool feature for an e-ink display.

Didn't get my hands dirty with the SDK yet, but will hopefully find some time during the holidays. It looks well thought out though, and the web IDE and emulator seem useful.

Really looking forward to dig into it.

[+] AmosLightnin|4 years ago|reply
Just got my Bangle.js 2 and like it very much. Also purchased a Watchy for the epaper display a few months back. Compared to Watchy, the espruino IDE and ecosystem for Bangle.js 2 is much more developed and the community much more active. There is support for widgets, custom settings, and apps other than watch faces, and the development / sharing path is much more thought through. Check out the app loader, and the 300 or so apps (all source available on github) here: https://banglejs.com/apps/
[+] noman-land|4 years ago|reply
I got a Bangle 1 and have the same problem about WebBluetooth and refusing to use Chrome. It's put a real damper in all my exciting hacking plans. I would love an alternative.
[+] Jugurtha|4 years ago|reply
I have worked for many years on fitness trackers from https://www.jointcorp.com. Talking with them, they sent PDF files for the communications protocol (Bluetooth Low Energy). I wrote a generic codec that consumes a YAML file and could decode packets from these devices to Python objects, and which could take a Python API call for a function you didn't write and encode it to binary packets the watch could understand. Practically, when we needed to use another device, I just added to the YAML file and the thing worked with practically no code change. New watch with GPS data? Just add to the YAML file and magic happens. Watch with blood pressure feature? Just add a few lines to the YAML file and magic happens.

The code was on a Raspberry PI in which a 3G/4G dongle was plugged, and it connected to the watch, uploaded data, was robust do disconnection events either internet or BLE (used Thespian and the Actor model to create and kill actors). The devices were geographically distributed on different timezones (a fucking nightmare) and basically needed to work for users with zero technical skills. It needed to be plug and play and it just works. Even configuring the pairing between a Raspberry PI and the watch needed to be low touch (I used the analogy of a dog and a hand: you put your hand out for the dog to smell and recognize you, you put the watch nearby the Raspberry PI and it computed the RSSI and duration to detect the "intent" so it didn't pair with "drive-by" devices). Kind of like NFC, but for BLE. The data was sent to a backend, then displayed on a mobile application (the prototype had a Grafana dashboard that showed your activity in near-real time).

Talk with them. They'll probably send you the PDF spec and you can do whatever you want.

[+] 41209|4 years ago|reply
That's cool, but I was trying to find a company that publishes it's SDK. Ideally some app examples as well.

That said, given how cheap these watches are I'm open to trying anything. Were you able to write your own custom app too, or just consume existing data ?

[+] h4waii|4 years ago|reply
You can still develop for Pebble, even though the entire thing is EoL. There are lots of Pebble enthusiasts and work is still being done on the platform through Rebble.

There's also Bangle.js to keep an eye on.

[+] modeless|4 years ago|reply
Yeah, Pebble has a great SDK and since it's defunct there's no update treadmill anymore. Anything you build today will be guaranteed to work as long as the hardware does.
[+] jsilence|4 years ago|reply
Maybe Watchy does what you want. No personal experience though. https://watchy.sqfmi.com/
[+] craftinator|4 years ago|reply
I have one, and have found it quite excellent. Easy to play around with, pretty good documentation, and the eink is really nice. There's something like 30 watch faces already designed, so you can just fork off one you like.

Highly recommend the anodized aluminum case. The plastic one is sturdy enough, but with the thickness of the material, makes the watch feel bulky. Also, the aluminum one has such a good fit (they are precision CNCed) that it can handle water splashes with no problem, and a few gaskets can get it to IP64 or 65

[+] atemerev|4 years ago|reply
There are many ESP32 smartwatches available on Aliexpress for about this price. ESP32 is compatible with Arduino IDE, PlatformIO, and many other development tools.
[+] alistairjallan|4 years ago|reply
The Lillygo or TTGO watches you'll find on AliExpress support Arduino libraries, Python, C or even JavaScript.
[+] sokoloff|4 years ago|reply
I picked up a (used) Series 3 Apple Watch for $100 early last year. If you got one of those, it’s surely going to be worth $50 in 12 months.

I’m in the Apple ecosystem and very happy with the watch, even though the newer versions are surely nicer.

[+] tinus_hn|4 years ago|reply
Apple Watch practically requires an iPhone though.
[+] evan_|4 years ago|reply
See if you can find a Timex Datalink on eBay