Is That An ESP32 On Your Wrist?

What could you do with a dual-core 240 MHz ESP32 that supports Arduino-style programming, with 16 MB of flash, 8 MB of PSRAM, and 520 k of RAM? Oh, let’s throw in a touchscreen, an accelerometer, Wifi, and Bluetooth. Besides that, it fits on your wrist and can show the time? That’s the proposition behind Lilygo T Watch 2020. If it sounds like a smartwatch, it is. At around $25 –and you can snag the hardware from a few different places — it is not only cheaper than the latest flagship smartwatch, but it is also infinitely more hackable.

OK, so the screen is only 1.54″, but then again, it is a watch. If Arduino isn’t your thing, you can use anything else that supports the ESP32 like Micropython or even Scratch. There are variants that have LoRA and GPS, at slightly higher prices. You can also find ones with heart rate monitors and other features.

If you would like a preview of the firmware, it is all there on GitHub and there is a smattering of documentation. There are even a few examples, although brush up on your Mandarin. The watch actually looks passable for a smartwatch, although the one blemish is that it is 20 mm thick.  That’s almost double the thickness of an Apple Watch 5 or a Samsung Active 2.

Still, if you want total hackability, that extra 10 mm is probably worth it. You can, of course, hack some watches that are not meant to be used this way. Besides, this watch is a bit more socially acceptable than one that would earn you hacker street cred.

38 thoughts on “Is That An ESP32 On Your Wrist?

  1. It seems that author mixed two versions of the TTGO Watch. Only older, thicker model is available on Aliexpress right now (as linked in the article). Watch 2020 (new model) is sold on Tindie.

      1. Which just means they’ll buy it on your behalf when/if it becomes available. If they can’t get any stock (or can’t get it cheap enough) they’ll leave you hanging indefinitely. No guarantee you’ll get it before people who order later on, either.

        I’ve had some experiences.

          1. Well, it’s a 350 mAh battery. I’m unsure about the esp32 sleep current, but all the other chips on the board are gonna use some power too. I’d hope the battery life is around a day

          2. 350mAh in what, 3 N size Nicads? :-D

            Yeah I should prolly look at the link but from the size quoted it seems big enough to swallow those LOL

  2. I don’t think it was ever shipped. It is still in preorder. Some informations are missing such as the battery capacity. But at that price, this is a great value, and very useful for many applications.

    1. mine arrives tomorrow. I expect the battery to not last a full day without some serious code changes and shutting down most of the on-board sensors.

      aka – same as the wrist-band they are currently selling.

      nice cheap fun devices but the boards are not optimized for low deep sleep current. feels like they are relying on the community to work on the code for them.

      fair enough at that price point.

      1. Go ahead for same price you can have embedded (or laptop/desktop with only socket and PTH) x86 board + 5-7″ display + buck/boost converter + few 18650 or “prismatic” a one for more space efficiency.
        DIY case up to your taste.
        Now you can have 3.5-5 cm thick wrist wearable device.
        Good luck!

  3. Having owned both the old format ttgo and bangle.js, the latter is streets ahead. Hackable but presentable. Polished docs and examples. Clever web Bluetooth programming environment. Albeit three times the cost. You get what you pay for…

  4. Looking at the image Szaja linked to, I would have to hope that it can easily be configured for left or right (in other words flipping the screen upside down), otherwise the winding crown (and other buttons?) is in a very awkward position for right-handed manipulation on a left wrist.

  5. I got mine from Banggood on 24/06/2020. Out of the box it was a bit of a disappointment because the graphics were upside-down – didn’t anyone notice? It was also hard coded to display the time in China, so even using the ntp time sync feature just game me an accurate time in China. The battery drain was also quite quick – no more than a days use if you were lucky. I tried some of the software in the github repo but it is all VERY basic. The LCD demo screen pictured in all the adverts is just a hard coded screen – the time will never change! The best example was examples/lvgl/SimpleWatch – this at least put the screen the correct way up but would still only display the time in China with horrendous battery drain. I set about changing the library to hard code GMT for the ntp sync and added daylight savings time – this stuff needs adding to the settings page which is currently empty! I added seconds and the day/date to the main watch screen and also managed to use light sleep mode which adds a couple of days to the battery. I then added double tapping anywhere on the watch to wake which seems to work ok. One thing that was incredibly impressive was the screen visibility in very bright direct sunlight. Thats all for now but I intend to add more when I can.

  6. I just opened mine and it is dead. I assume it needs to be charged, but after some googling I still can’t figure out where to plug it in. Maybe under that rectangular button, but I can’t get the cover to pop out (if it is a cover) and don’t want to break it…

    1. Look under the silver elongated button, there is a bit to get your nail in and pop it open.
      Also on the back there is a similar fingernail gap in one of the corners to pop the back off.

  7. I just got my TTGO 2020 V1 in the mail so here’s a 10 minute review. It’s still very chunky, it’s like wearing a tv on my hand. It may kind of look like a knock-off Apple watch but the size is nowhere near it. If you see it for what it is, a super hackable platform, it’s very very nice. The firmware it came with was hilariously crap, so I flashed the latest one from their Github. comes as a PlatformIO project, very nice, just click upload and it’s up. The latest firmware is still laughable, but it does SOME THINGS. It took me 5 minutes to figure out the right way to swipe for it to register it as an actual swipe :)).
    The battery meter never reads 100%, author says it’s due to a hardware issue, gonna investigate.
    The hardware button doesn’t seem to be accessible to the ESP32, it seems to turn the power on-off at the power-chip level (crazy stupid choice), at least according to the documentation, will have to check when I take it apart. From what the firmware behaves like, it’s plausible, it seems to boot from scratch every time you turn it on from the button.
    Some of the firmware features are quite funny, especially the SUPER TINY on-screen keyboard (full qwerty layout on a tiny LCD, yet it seems to work pretty well).
    The screen looks very nice, there seems to be some ghosting in some situations, but it might just be the firmware leaving a see-through version of the clock.. unsure yet.
    If someone decides to write a less retarded firmware for this, it could be VERY cool. It has a lot of cool hardware baked in that’s barely taken advantage of in the firmware. Considering the insane things people are doing on the ESP32 platform, there’s a lot of room for amazing stuff.

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