Hi. Today I'd like to introduce my EPD project. The EPD is electronic paper display. It is used to e-book reader. The representative products are Amazon Kindle and SONY e-book reader.
The EPD has any interesting characteristics. It looks like printed paper and the image has shown if the power is cut off.
I want to display the information (for examples the weather forecast, the figure of atmospheric pressure change and so on) what it get from on the internet. Now project status is that the EPD displayed image was read from SD Card.(But it has any problems yet.)
The following figure is shown a block diagram for that.
There are 5 blocks.
1. ED050SC3 Electric Paper Display
The almost kind of EPD has a specially connector. It is difficult to get and expensive. But ED050SC3(LF) has FFC/FPC connector. It is not specially connector. I could get the connector easily.
2. ESP-WROOM-02(ESP8266) Development board
The ESP8266 is cheapest Wifi microcontroller.
I choose ESP-WROOM-02 Developer Board from any kind of ESP8266 modules. Because ESP-WROOM-02 is the only passed
the TELEC( like a Japanese FCC).If you use at out of japan, you choice NodeMCU better. May be function the same.
3. DCDC Power Convertor
The ED050SC3(LF) needs many kind of voltage power sources. +22V, +15V, -20V, -15V, +3.3V and -2V. These are converted from +5V USB bus power by DCDC convertor. These are also needed power on sequence and a small scheme for -2V.
4. 16bit Shift Register
The ED050SC3(LF) needs at least 6 lines for control signals and 8 lines for data transfer. ESP8266 has a few GPIO pins. So they pins ware extended by two 74HC595 shift register ICs tied to SPI. But 74HC595 made some problems. I will tell you details later.
5. SD Card
The images data for display are stored to SD card.I choose micro SD card. Because it was small.
Contents of the EPD project
- The project outline ( you are here )
- The ED050SC3 EPD
- The ESP8266( ESP-WROOM-02)
- The Power block
- The 16bit shift register
- The SD card and serial RAM