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e-Paper ESP8266 Driver Board User Manual

e-Paper ESP866 Driver Board

USER MANUAL

PRODUCT OVERVIEW

 e-Paper ESP866 Driver Board is hardware and software tool intended for loading pictures

to an e-Paper from PC/smart phone internet browser via Wi-Fi net.

 The hardware of the driver board is a small PCB with e-Paper driver and ESP8622 module.

The PCB has two series of pins, which allow you to apply all of Arduino projects for ESP8266

boards.

 The software of the driver board is a one-page html-application providing picture

correction service (is useful in that case if original colors and size aren’t suitable for the

currently used display) and uploading it to the e-Paper.

PRODUCT FEATURES

 No need to convert a picture to special image formats, it can be any image format

supported by your browser.

 E-Papers have 2, 3, 4 hardware colors, but the driver board can mix them (by the Dithering)

to obtain more color combinations for better image shade rendering of the original picture.

 The hardware of the driver board needs a connection to LAN, but it doesn't need the

internet connection.

APPLICATIONS

The tool is intended to be the start point in developing of the electrically changeable sign based

on e-Paper display. Possible applications are:

 Price tags in a supermarket;

 Small information screen in the customer service window (clerk’s name);

 Advertising screen in lift near buttons of the control panel;

Summary of content (17 pages)

PAGE 1
e-Paper ESP8266 Driver Board User Manual e-Paper ESP866 Driver Board USER MANUAL PRODUCT OVERVIEW  e-Paper ESP866 Driver Board is hardware and software tool intended for loading pictures to an e-Paper from PC/smart phone internet browser via Wi-Fi net.  The hardware of the driver board is a small PCB with e-Paper driver and ESP8622 module. The PCB has two series of pins, which allow you to apply all of Arduino projects for ESP8266 boards.
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e-Paper ESP8266 Driver Board User Manual CONTENT Product Overview.......................................................................................................................................................... 1 Product Features .................................................................................................................................................. 1 Applications ..............................................................................................................
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e-Paper ESP8266 Driver Board User Manual SEVER_SIDE APPLICATION The e-Paper Image Loader described in this document is a source code written in C language. To compile the source code of the e-Paper Image Loader you need the Arduino IDE. To run the driver board you need also a serial port monitoring software (you can use Arduino IDE’s or other software with a serial port monitoring function), Wi-Fi router and PC / smart phone connected to the router.
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e-Paper ESP8266 Driver Board User Manual SOURCE CODE COMPILATI ON The source code consists of following files:  loader.ino is the main file. It has two functions: setup and loop. If you need to add/initialize some other software components, do it in setup function.  srvr.h describes functions of ESP8266 Wi-Fi server. To compile and run the loader as it is you just need to change constants ssid and password as in your Wi-Fi router.  html.h, css.h and scripts.
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e-Paper ESP8266 Driver Board User Manual E-PAPER TYPE SETTING Before you send some picture to your e-Paper, check please the trigger on the board is in proper state (Figure 4). Find your type of display in table 1 and set the trigger to right position: Trigger state e-Paper type A 1.54 inch, 2.13 inch, 2.9 inch 1.54 inch(b), 2.13 inch(b), 2.7 inch, 2.7 inch(b), 2.9 inch(b), 4.2 inch, 4.2 B inch (b), 7.5 inch(b), 7.
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e-Paper ESP8266 Driver Board User Manual USER INTERFACE The application user interface has following controls (figure 5):  Select image file – opens the file browser;  Level: black, Level: black and red, Dithering: black, Dithering: black and red - make a new picture based on opened image with proper size and colors;  Upload image – makes a POST request with the type of e-Paper, sends it to the serverside application and waits response ‘Ok’, sends the processed image part by part;  Device IP: sh
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e-Paper ESP8266 Driver Board User Manual IMAGE PROCESSING The client-side application provides two kinds of image processing: Level and Dithering. LEVEL The Level supposes that that image can be divided on a few large regions, in which all of pixels have color ‘close’ to one of available colors: black, white or red and ‘far’ to others available colors. This kind of processing is suitable for 2- or 3-color schematics or texts.
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e-Paper ESP8266 Driver Board User Manual DITHERING In case of smooth colored pictures during the Level processing an image looses a lot of thin details expressed by smooth gradient of colors situated close to each other in the color diagram. The most of gradients cover large areas of pictures taken by camera, thus it is possible to express some shades by mixing closest available colors on those areas. Eyes feel the average color of pixels in a small area.
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e-Paper ESP8266 Driver Board User Manual previous iteration of the algorithm. See examples of the photographic image processing in figures 9, 10 and 11. Figure 2 Original Image Figure 1 “LEVEL Black” and “LEVEL RED and Black” Figure 3 “Dithering: black” and “Dithering: black and red” DATA TRANSMISSION PROTOCOL The ESP8266 module is intended for sending short messages and can be used neither for video streaming, nor for sending large pictures.
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e-Paper ESP8266 Driver Board User Manual via HTML page and Wi-Fi net in haste then you can use the solution described in this document. It is based on POST request data transmission, but isn’t “the bad practice” (as if it’s based on GET request). Consider the data transmission mechanism of this solution, modificate it or add your own functions/commands if you need.
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e-Paper ESP8266 Driver Board User Manual Important: before the first writing of the image data into a display, one of commands: WRITE_RAM, DATA_START_TRANSMISSION_1 or DATA_START_TRANSMISSION_2 is required,
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e-Paper ESP8266 Driver Board User Manual but 2.13-display can load data line by line only. It means before the image data writing of each line, the command WRITE_RAM must be executed. DATA TRANSMISSION ALGORITHM Every time the server gets some request, it sends the word “OK” (in case of known command), otherwise the index html page.
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e-Paper ESP8266 Driver Board User Manual DATA PIXEL FORMAT When your browser opens an image file, the pixel format is 24 bpp by default. The image processing reduces it to 1 bpp (white-black display): 0 – white; 1 – black; or 2 bpp (white-black-red display): 0 – white; 1 – black; 2 – gray (1.54 inch b-type only); 3 – red.
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e-Paper ESP8266 Driver Board User Manual Before the xhReq object sends a POST-request to the server, the client-side application packs image data into bytes or words. The bits order in these bytes/wordas is native display memory order or is suitable for fast conversion into the native orser. The table 2 shows this changes from the start of conversion to the writing of data into display’s memory: Display type Transmission format (channel) (p – pixel, b - bits) Native format 1.
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e-Paper ESP8266 Driver Board User Manual 0000 (0) – black; 0011 (3) – white. 1.54b (black) p:0 – b:1,0; p:0 – b:7,6; p:1 – b:3,2; p:1 – b:5,4; p:2 – b:5,4; p:2 – b:3,2; p:3 – b:7,6; p:3 – b:1,0; 00 (0) – black; 00 (0) – black; 01 (1) – white; 01 (1) – gray; 10 (2) – gray; 11 (3) – white; 11 (3) – red, is read as 10 (2). 7.
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e-Paper ESP8266 Driver Board User Manual HARDWARE The board of the E-Paper Image Loader is developed to control an e-Paper display by WiFi net, but the EPS-8266 module allows performing a lot of other useful functions the same time: keep loaded images in SD-card or external flash memory, get data from sensors and display them in e-Paper, and so on.
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e-Paper ESP8266 Driver Board User Manual OUTLINE DIMENSION