Exactly as described, IoT watch with SmartWatch form factor
For LILYGO® TTGO T-Watch-2020
I was careful about reading the descriptions. I'm an IoT developer with a small pile of ESP32 and similar devices on my desk right now. I was looking for a portable device that I could program, and this fit the bill.
While it *LOOKS* similar in size to an Apple Watch or Android watch, it is not. Clearly from the reviews many people were fooled by that. Personally I love this, as previously I have used shrink-tubing melted around soldered components, which does not look good.
It is an IoT device, and the advertisements focus on the hardware in the box. While I usually attach better sensors to my IoT devices, for example using a 9-axis accel/gyro/magnet sensor instead of a 3 axis, the sensor provides enough information for a range of IoT projects.
Most ESP32 boards come with 4 MB of flash space, this ships with 16 MB. By default the 16MB is partitioned as 6MB for the executable, 3.6MB for SPIFFS file data, 6MB for uploading/transferring a new executable, 8KB for over-the-air data updates, and 20KB for applications settings, but they are adjustable. My app is currently floating around 2MB, so I have been considering shifting 4MB from both the executable and transfer space, giving an extra 8 to SPIFFS for for 11.6MB of file data space, but so far haven't needed the storage.
Similarly, ESP32 boards have a variety of memory sizes and can come with as little as 520KB (a half megabyte) of RAM. The device ships with 8MB of ram. Due to ESP32's architecture and much like older PCs and Macs before around 1995, only part of the memory can be actively paged in at a time. Working with PSRam is very similar to working with the Expanded Memory System used by DOS. If you don't do anything special you get access to 4MB, but the paging system allows access to all 8MB.
I have used it to attach to other IoT devices, using WiFi, Bluetooth Low Energy (BLE), and Espressif's custom ESP-NOW communications system between ESP32 devices. It is a very convenient tool for connecting to my devices.
The screen drains battery like crazy, and WiFi has always been a power drain for ESP32 chips, so beware of both if you want good battery life. Dim the screen as much as possible, and don't use WiFi if you can help it. But even these are basics of IoT programming, not specific to this device.
I found the documentation relatively good in Github, listing all the pins and ports. You as the programmer still need to know what to do with them, but listening on interrupt pins and such works. The documentation is similar to the many other devices I program. It is available as a reference, it isn't a tutorial on how to program.
I had an issue with the shell having a manufacturing defect on arrival. The plastic back had a large crack which has now spread across the entire back face. I have contacted LilyGo who said they will make it right. I'm still waiting but hope that will be resolved soon.
Response from Lilygo | Aug. 31, 2020
Hello , thanks for your feedback about our product in detail , we believe this will help others to understand our products better . about the back face , we have made improvement to it recently , it is PC+ABS material now , which will be resend to you later , we have also contacted you via email .
