Inspired by the famous Word Clock, this project created a word clock that consists of Chinese characters. Driven by an ESP8266, this clock synchronize time from NTP servers automatically.
The clock itself is a 7x10 LED matrix consists of 70 WS2812b RGB LEDs, cut from an LED strip. The microcontroller is an ESP8266 DevKit, which provides Micro-USB interface used to power the ESP8266 and the LEDs.
WS2812b RGB consumes a lot of power. When displaying white color in full brightness, it consumes about 60mA at 5V (20mA per R, G, B color). In the worst case, there are 16 LEDs being turned on (e.g. "十二月二十四日晚上十一点五十六分"), which consumes 60mA * 16 = 960mA.
Also, according to the datasheet of ESP8266, it consumes about 170mA when using WiFi.
So the total current is about 1.2A. Therefore, a USB power adapter at least 1.5A is required.
Also note that 1.2A goes way beyond the 500mA limit that computer USB ports could provide. When debugging / developing programs on the computer, make sure to use a small brightness.
The frame is an IDEA RIBBA 13cm x 18cm Picture Frame. This frame is inexpensive, and is thick enough to hide electronic components inside. It is a good choice for similar electronic projects.
In the STL folder I provided the STL files used in these project.
The program is written with Arduino.
The whole program consists of the following parts:
ChineseWordMatrix.*: convert timestamps to LED indicies.EEPROMConfig.*,ESP8266AutoConfig.*,WiFiConfig.*: provides the WiFi management functionality.Animation.*: implements the fade in/fade out/breathing animations.
本项目是一个汉字版本的文字钟，通过钟面上的汉字来显示时间。创意来自Word Clock。 微控制器为ESP8266，因此设备支持WiFi，并且可以自动从NTP服务器同步时间。
钟面本身由70个 WS2812b RGB LED组成。LED来自一条RGB LED灯带。微控制器为一块ESP8266开发板， 可以通过Micro-USB为ESP8266和LED供电。
WS2812b RGB LED本身会消耗很大电力。在以最大亮度显示白色时，一颗RGB大约产生60mA的电流（红黄蓝每种颜色各20mA）。 在最坏的情况下，会有16个LED同时亮起（例如“十二月十二四日晚上十一点五十六分”），此时产生的电流为 60mA * 16 = 960mA。
另外，根据ESP8266的数据手册，在使用WiFi时， ESP8266会产生大约170mA的电流。
总电流约为1.2A。因此，需要使用至少1.5A的USB适配器来供电。
另外，1.2A已远远超过了电脑的USB接口能提供的500mA限制。因此在开发或调试时，务必将brightness设为一个较小的值。
框体采用的是宜家的RIBBA 15cm x 18cm 相框. 这款相框非常便宜，而且足够厚，内部可以容纳许多电子元件，非常适合类似的项目。
STL文件夹下提供了本项目用到的STL文件。
程序基于Arduino。
整个程序由以下模块组成：
ChineseWordMatrix.*：负责将时间戳转换成LED的序号。EEPROMConfig.*,ESP8266AutoConfig.*,WiFiConfig.*：负责WiFi管理和配置。Animation.*：用于产生渐入/渐出和呼吸效果的动画。
Shield:
This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
