I liked it so much I bought another
For LILYGO® TTGO T-Watch-2020
This is my first time with Lilygo and the Espresif platform. The first thing you need to know is that this is not a watch, its a wearable compute platform with very minimal software installed. You **WILL** have to do some programming to do anything with it, unless you live in China. The installed firmware has lots of settings screens that are nothing more than an icon, but thankfully the WiFi and NTP settings work out of the box. However there is no way to set a time zone in the UI. The firmware installed on the watch is simply to give a developer ideas. I was disappointed that that firmware didn't look like what they showed in the photos, but that is apparently the "LilygoGui" example supplied in the SDK. The software that is installed at the factory appears to be the "SimpleWatch" example.
I wanted a watch I could completely customize and had been contemplating building an ATmega based solution but I can't build a wearable case at this time. This was definitely what I was looking for and the ESP32 and supporting hardware is way more than I was thinking of, unless you compare it to a wrist worn OrangePI Zero... The quality of the watch case is superb, feels nice on the wrist and is solid.
As a programmable computery thing on my wrist that can be a watch too I find this was everything I wanted and more. I have only two complaints: documentation and battery. The battery issue is two fold: so far I have been hard pressed to get the battery to last the daylight hours. Definitely have to charge it every night and you might have to get it to that charger sooner than you wanted. I have hopes I can alter the firmware to stretch that out.
The second problem with the battery is getting it to charge. This seems to be a common problem with anything using a micro USB connector, now days. I have several devices that charge this way and they are all fiddly. If you don't do something to put and maintain the proper stress on the connector it simply won't charge, or it will start to and quite while you aren't looking. The cable supplied with the watch works pretty good but is only about 8 inches long. Opening the USB port on the watch can also be a bit of a challenge unless you have fairly thin finger nails. A plastic case opening tool, like those sold to fix iPhones, will be of benefit here.
The documentation, as is so often the case, is lacking. Hence the guess work about what software comes shipped on the device. Be prepared to go spelunking through the source code. And by source code I mean: Lilygo's source code, the Espresif board support code and the GUI and other supporting library sources. All told there is a lot of code to dig through. I spent a month of spare time just trying to figure out the secret of setting the timezone. And I don't believe my hunt is completely over. My original intent being to just use it as a watch until I had the time to really get to know the uController and supplied accessories. Actually it was easier to make visual changes than set the time zone.
So for others who want to use this as a watch to set the timezone you'll need to copy the SimpleWatch example app, open the "gui.cpp" file and change the "RTC_TIME_ZONE" constant. This has a weird format and is exactly opposite of what you want. Use something like this: "UTC7DST8" (US Pacific Time). You can add "+" in front of the numbers or leave it off. If you need a negative offset use a dash prior to the number. The two three letter sets seem to be meaningless other than as separators. The UTC time offset is reversed. The pacific timezone is normally UTC-8, but its +8 in this string.
The eagle-eyed among you will also note the standard time and daylight savings time offsets are backwards. I kept coming up with time an hour off in the wrong direction without doing that. I might have to swap those when daylight time ends as I still don't know what its using to determine if its DST or not. I also tried specifying a single offset ("UTC7") and it still shifted the time an hour. One could simply compensate for that but I have hopes that it will return to standard time automatically... we shall see.
Response from Lilygo | Aug. 4, 2020
Thank you for purchasing T-WATCH, yes, it is an ESP32 development platform , we have installed one of the routines, and we are also optimizing and updating more routines in future . about battery, we will also add this part in the next routine.
