Difference between revisions of "E-Paper ESP32 Driver Board"
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[[File:colorscale.png]]<br/> | [[File:colorscale.png]]<br/> | ||
For color images, we all know that RGB has three color channels. Compared with the red channel, we can refer to blue and green as the blue-green channel, or the non-red channel. According to the figure below, a pixel on a color image, if it has a high value in the red channel, but a low value in the blue-green channel, we classify it as a red pixel; if its red channel and blue- If the green channel has low values, we classify it as a black pixel; if the red and blue-green channel values are high, we classify it as white.<br/> | For color images, we all know that RGB has three color channels. Compared with the red channel, we can refer to blue and green as the blue-green channel, or the non-red channel. According to the figure below, a pixel on a color image, if it has a high value in the red channel, but a low value in the blue-green channel, we classify it as a red pixel; if its red channel and blue- If the green channel has low values, we classify it as a black pixel; if the red and blue-green channel values are high, we classify it as white.<br/> | ||
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In the algorithm, the color definition is calculated based on the difference between the RGB value and the sum of the squares of the expected color value. The expected color value refers to the color value that the pixel is closest to, and these values are stored in the curPal array<br/> | In the algorithm, the color definition is calculated based on the difference between the RGB value and the sum of the squares of the expected color value. The expected color value refers to the color value that the pixel is closest to, and these values are stored in the curPal array<br/> | ||
[[File:colordoth2.png]]<br/> | [[File:colordoth2.png]]<br/> | ||
Revision as of 08:12, 17 May 2022
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Introduction
Universal e-Paper Driver HAT, Onboard ESP32, supports various Waveshare SPI interface e-Paper raw panels. Supports refreshing image to e-paper via WIFI or Bluetooth. It also supports Arduino.
| More |
Parameter
- WiFi Standard: 802.11b/g/n
- Communication Interface: SPI
- Bluetooth Standard: 4.2, BR/EDR and BLE included
- Communication Interface: 3-Wire SPI, 4-wire SPI (default)
- Working voltage: 5V
- Working Current: 50mA-150mA
- Outline dimension: 29.46mm x 48.25mm
Pin
| Pin | ESP32 | Description |
|---|---|---|
| VCC | 3.3V | Power input |
| GND | GND | Power ground |
| SCK | P13 | SPI CLK, Clock Signal Input |
| DIN | P14 | SPI MOSI, Data Input |
| CS | P15 | Chip Select, active-low |
| BUSY | P25 | Busy Output Pin (means busy) |
| RST | P26 | Reset, active-low |
| DC | P27 | Reset, Data/Demand, low level means to demand, high level means data |
PS: The above is the board fixed connection, no additional operation by the user
Feature
- Onboard ESP32, support Arduino development
- Provide Android mobile APP program, which can update the display content through Bluetooth EDR, easy to use
- Provide HTML host computer program, which can remotely update the display content through the web page, which is convenient to integrate into various network applications
- Supports Floyd-Steinberg dithering algorithm for more color combinations and better shadow of the original image
- Supports many common image formats (BMP, JPEG, GIF, PNG, etc.)
- Factory built-in e-ink screen driver (open source)
- 5V pin supports 3.6V to 5.5V voltage input, can be powered by lithium battery
- Provide complete supporting information manual
Application
This product cooperates with the ink screen and is suitable for the application scenario of wireless brushing.
- Supermarket electronic price tag
- Electronic name card
- Serial information display board, etc.
Preparation
Hardware Connection
This product is shipped with an ESP32 network driver board, an adapter board and an FFC extension cable.
When using it, you can directly connect the screen to the driver board, or connect it through extension cables and adapter boards.
- Connect the screen to the ESP32 driver board:
Direct access to the driver board:
Access via extension cord:
Set the model switch: Set the No. 1 switch according to the model of the ink screen used. There are many screens. If it is not listed, please use 'A' to try. If the display effect is poor or cannot be driven, please try to switch the switch
- Turn on the serial port module: Toggle the No. 2 switch to "ON", this switch controls the power supply of the CP2102 (USB to UART module). When you don't need to use it, you can manually turn off the module to save power (if the switch 2 is in the OFF state, you cannot upload the program)
- Use a micro USB cable to connect the ESP32 driver board to a computer or 5V power supply
Download Demo
We provide three kinds of demos: local, bluetooth, and WiFi. The sample program can be found in the "Information" tab of this page, or click the sample program to download
Unzip the downloaded compressed package, you can get the following files:demo example
- ePape_Esp32_Loader_APP: Bluetooth App source code (Android Studio)
- examples: local demo
- Loader_esp32bt: Bluetooth demos
- Loader_esp32wf: WiFi demo
- app-release.apk: Bluetooth routine App installation package
Environment Configuration
- If the Arduino IDE is not installed on your computer before, or the version of the IDE is older. It is recommended to go to the Arduino official website to download the latest IDE and install it according to your own system.
Official link: https://www.arduino.cc/en/Main/Software
Download the ESP32 Dev Module management tool:
1. Open the preferences of the arduino software and add a link to the add-on board manager URL: https://dl.espressif.com/dl/package_esp32_index.json
After the addition is complete, open Tools -> Development Board -> Development Board Management Tool, and manually search for "ESP32" to download and install the latest version.
3. After the installation is complete, you can find the model option of ESP32 Dev Module in Tools - Boards of IDE.
If the installation cannot be completed due to repeated errors, please contact the after-sales technicians.
Image Processing Algorithms
In the Bluetooth and WiFi demos, two image processing algorithms are provided, namely Level and Dithering color scale method
An image can be divided into several large color gamuts, and each pixel on the image is divided into these color gamuts according to how close the color is to these color gamuts. This method is more suitable for images with few colors, such as bright or tri-color shapes or text images. Taking the black and white and red ink screen as an example, when processing the image, we hope to process it into black, white and red, so for an image, we can divide all the colors of the image into three large color areas: the black area , white area, red area.
For example, according to the figure below, if the value of a pixel in the grayscale image is equal to or less than 127, we regard this pixel as a black pixel, otherwise, it is white
For color images, we all know that RGB has three color channels. Compared with the red channel, we can refer to blue and green as the blue-green channel, or the non-red channel. According to the figure below, a pixel on a color image, if it has a high value in the red channel, but a low value in the blue-green channel, we classify it as a red pixel; if its red channel and blue- If the green channel has low values, we classify it as a black pixel; if the red and blue-green channel values are high, we classify it as white.
In the algorithm, the color definition is calculated based on the difference between the RGB value and the sum of the squares of the expected color value. The expected color value refers to the color value that the pixel is closest to, and these values are stored in the curPal array
Bluetooth Examples
Download example
- Go to the Loader_esp32bt directory, double click the Loader_esp32bt.ino file to open the example.
- Choose Tools->Boards->ESP32 Dev Module and select the correct Port according to Device Manager: Tools->Port
- Click the Upload icon to build the project and upload it to the ESP32 driver board.
- Install the APP to Android board and open it：
- APP has five buttons on the main page:
- BLUETOOTH CONNECTION: This button is used to connect the ESP32 device via Bluetooth.
- SELECT DISPLAY TYPE: This button is used to select the type of display according to what you buy.
- LOAD IMAGE FILE: Click it and choose a picture to open. It is only available after choosing the display type.
- SELECT IMAGE FILTER: This button is used to choose the image process method.
- UPLOAD IMAGE: Upload the processed image to ESP32 driver board and update to e-Paper display.
- BLUETOOTH CONNECTION: This button is used to connect the ESP32 device via Bluetooth.
- Please first open the Bluetooth function of your phone. Click the BLUETOOTH CONNECTION button -> Click the SCAN icon on the top-right to scan the Bluetooth device.
- Find the ESP32 device and connect. If your phone is the first time to connect this device, it requires to pair, complete the pairing process according to the prompt.(Note: The APP cannot work with pairing.)
- Click "SELECT DISPLAY TYPE" to choose the display type.
- Click "LOAD IMAGE FILE" To choose a picture from your phone and cut it.
- Click " SELECT IMAGE FILTER" to choose a process algorithm and confirm.
- "LEVEL:MONO": This option will process the picture to a monochrome image.
- "LEVEL"COLOR": This option will process the picture to the tricolor image according to the display colors of the display (only valid for colorful displays).
- "DITHERING:MONO": This option will process the picture to a monochrome image.
- "DITHERING:COLOR": This option will process the picture to the tricolor image according to the display colors of the display (only valid for colorful displays).
- Click "UPLOAD IMAGE" to upload the image to the ESP32 device and display it.
WiFi Examples
How to Use
- Go to the Loader_esp32wf directory, double click Loader_esp32wf.ino file to open the project.
- Choose Tools->Boards->ESP32 Dev Module in IDE menu, and select the correct COM port:Tools->Port
- Open the srvr.h file, modify the ssid and password to your actual WiFi used.
- Click the Upload icon to build the project and upload it to the ESP32 driver board.
- Open the serial monitor, set the baud rate to 115200. Then you can get the information printed like the IP of the ESP32 board.
- Open a browser on the PC or mobile phone (Note that you should connect your PC/Phone to the same network as the ESP32 board), go to the webpage with the IP address of the ESP32 board:
- There are five areas in the webpage：
- Image Operation：
Select Image file: Click the option to choose a picture from PC/phone
- Image Operation：
Level: mono: Black/White image level processing.
Level: color: Colorful image level processing (only valid for colorful display)
Dithering: mono: Black/White image Dithering processing
Dithering: color: Colorful image Dithering processing (only valid for colorful display)
Update image: Upload image to ESP32 board and display it.
- IP Information: In this are, the IP information of the ESP32 board connected is listed.
- Image Size Setting: x and y is the beginning position on the image. For example, if you select an image with 800x480 resolution, and the display you connect is the 2.13. The 2.13inch display cannot display the whole picture, the codes will crop the picture according to the resolution of displays. If you set the x and y, the codes will set the (x, y) as the being pixel where it starts to crop. w and h is the resolution of the displays choose.
Note: If you modify the x and y value, you need to click the Level or Dithering options to process the image again.
- Display Type: You should first select the display size here according to the display used.
- Image Preview: it will display the original image selected and the image processed.
- PS: The upload progress value is printed at the bottom of the webpage when uploading.
For examples:
- In area ① click Select image file to choose a picture, you can also drag the picture to the Original image area directly.
- In area ④ choose the type according to the display, for example 1.54b
- In area ① choose an algorithm to process the image, for example Dithering: color
- In area ① click Upload image to upload the image and display.
Offline Examples
Download example
- Go to examples\ directory. copy the whole esp32-waveshare-epd folder to [Installation directory of Arduino IDE]\hardware\espressif\esp32\libraries
- Open the Arduino IDE, Find the wareshare-e-Paper examples from File->Example, and select one according to the display type.
- Click Upload to build the project and upload it to the ESP32 board. You can open the Serial Monitor to check the debug information.
Resources
Documentation
Demo Code
Related Resources
This is a post in Arduino Form about our SPI e-Paper thanks to ZinggJM, maybe you want to refer to.
FAQ
- Open epd1in13.h in the project and change the following value to 1
- Set the model: Set the No. 1 switch according to the E-Paper model you are using. There are many models of the E-Paper. If the model you used is not listed, please use ‘A’ first to try.
- Turn on the serial port module: Turn the No. 2 switches to "ON", this switch controls the power supply of the CP2102 (USB to UART module). When you don’t need to use it, you can manually turn off the module to save power (if the No. 2 switch is in the OFF state, the device cannot upload the program)
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Support
Support
If you require technical support, please go to the Support page and open a tickets.