EPDiy E-Paper Driver

EPDiy is a driver board which talks to affordable E-Paper (or E-Ink) screens, which are usually sold as replacement screens for E-Book readers. Why are they interesting?

• Easy on the eyes and paper-like aesthetics
• No power consumption when not updating
• Sunlight-readable

Ready-made DIY modules for this size and with 4bpp (16 Grayscale) color support are currently quite expensive and / or slow. The EPDiy controller can drive the bare display modules, e.g. from old e-Readers, which are available for 20$ (small) / 30$ (large) on ebay! Additionally, since it is based on the ESP32S3 (V7) / ESP32 (V2-V6) microcontroller, it features WiFi and Bluetooth connectivity.

The EPDiy driver board targets a range of E-Paper displays, as shown in the table below. As the driving method for all matrix-based E-ink displays is more or less the same, only the right connector and timings are needed. The current V7 board has three different display connectors, other display will require an adapter board.

The controller is optimized for the use with LiPo batteries, featuring a LiPo charger and ultra-low deep sleep current.

This project supports a driver for the ESP-IDF and Arduino. For installation instructions, please refer to the documentation. Note that for epdiy V7, update speeds are significantly lower when using the Arduino IDE, because it does not allow to change the sub-optimal cache configuration.

Get Inspired

The examples directory contains some example applications like a weather station or a screen diagnostic test. If you want to build something more useful though, how about:

• A serial terminal for connecting to a raspberry pi: video repository]
• A Music Player Daemon (MPD) dashboard: repository]
• Firmware for displaying images directly from Immich (Self-Hosted Photo Management) epdiy-immich
• An e-Paper picture frame: video
• And more to come!

Building It

On the EPDiy Hardware Page, you'll find a list of all boards and variants, adapters, and helpers. Next to each board, there are manufacturing files (gerbers), Bill of Materials (BoM), part placement files, and 3D models ready to use!

For ordering from JLCPCB for example, ordering is as easy as downloading the zipped gerbers, BoM, and placement file and uploading them. The process is very similar for other manufacturers, check your vendor's documentation for details. Don't forget to oder adapters if the board doesn't have connectors for your specific display.

The current latest version is epdiy V7, beased on the ESP32S3. Older versions are also available on the hardware page.

Contributing Hardware

Want to contribute your own board variant or adapter? Check out the epdiy-hardware repository for instructions.

Gettings Started

For instructions and more information visit the documentation!

Join the Discussion

• Matrix Community: +epdiy:matrix.vroland.de
• Slack: See badge

Displays

Troubleshooting

The following list is compiled from past experiences and GitHub issues:

• The displayed image displays only part of the image. Make sure to select the correct display type as described here.
• The existing image fades / darkens when updating a partial screen region. Make sure the VCOM voltage is calibrated for your specific display.
• The second third of the image is replaced with the last third. This seems to be a timing issue we could not yet quite figure out the reason for. For a workarround or suggestions please join the discussion.
• The ESP does not boot correctly when external periperals are connected. Make sure not to pull GPIO12 high during boot, as it is a strapping pin internal voltage selection (https://github.com/vroland/epdiy/issues/17).
• The ESP power consumption in deep sleep is too high. Add rtc_gpio_isolate(GPIO_NUM_12); to your solution. See also Configuring IOs (Deep-sleep Only).

LilyGo Boards

Supported LilyGo Boards

Power Management

There are several differences with these boards. One particular one is the way the LilyGo handles power to the display the official lilygo code has two states. This is now handled in epdiy in a different way to the lilygo code. epd_poweroff() completely turns the power off to the display and the other peripherals of the lilygo. The new function epd_powerdown() keeps the peripherals on (this allows the touch functions to continue to work). epd_poweroff() should always be called before sleeping the system You can still use touch to wake the screen with the following. In Arduino it works like this. epd_poweroff();

epd_deinit();

esp_sleep_enable_ext1_wakeup(GPIO_SEL_13, ESP_EXT1_WAKEUP_ANY_HIGH);

esp_deep_sleep_start();

I2C Bus Sharing

EPDIY now uses the ESP-IDF master bus/device I2C driver on IDF 5.x and newer.

Existing programs can keep calling epd_init(...) and EPDIY will create and own the board's default I2C bus.

If your application already owns an ESP-IDF I2C master bus, pass it in during initialization:

i2c_master_bus_handle_t bus = ...;
EpdI2cConfig i2c_config = {
    .bus_handle = bus,
};
EpdInitConfig init_config = {
    .i2c = &i2c_config,
};

epd_init_with_config(&epd_board_v7, &ED047TC1, EPD_LUT_64K, &init_config);

When a bus handle is provided, EPDIY will attach its TPS65185/PCA9555 devices to that bus and leave bus ownership to the caller.

More on E-Paper Displays

• List of E-Paper devices and their screens: https://e-ink-reader.ru/chg_dsp_en.php (thanks, @mcer12)
• Reverse engineering of display pins, possible starting point for alternative drivers: https://linux-sunxi.org/PocketBook_Touch_Lux_3 (thanks, @mcer12)
• Reverse engineering and explanation on driving EPDs: http://essentialscrap.com/eink/index.html
• Earlier take on driving 6" EPDs with an ESP32, basis of original power circuit: http://spritesmods.com/?art=einkdisplay&page=1
• Related Hackaday projects: https://hackaday.io/project/21607 https://hackaday.io/project/11537

If you know any other useful resources or have suggestions, please comment on #31!

Hackaday Project

For more details, see the project page on Hackaday: https://hackaday.io/project/168193-epdiy-976-e-paper-controller

Licenses

The weather example is Copyright (c) David Bird 2018 (except for minor modifications). Please refer to examples/weather/README.md for details.

The board and schematic are licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.

Firmware and remaining examples are licensed under the terms of the GNU Lesser GPL version 3. Utilities are licensed under the terms of the MIT license.