Any Waveshare e-Paper module experts, please help

Other Hardware Displays
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Hi, I am trying to do a project involving refreshing an image periodically on to an e-Paper module, driven by a low-power wi-fi board such as ESP32.

After much googling, trying different things, and purchasing different boards, I have still not succeeded in illuminating a single pixel on my 4.2inch 400x300 Waveshare e-Paper module (search B07Q6VBF89 on Amazon).

I own the following boards:

  • HELTEC HTIT-WB32. I realised after purchasing this and much experimentation, that it seems actually unsuitable for what I am trying to do because the required pins are already used for the onboard LED module
  • This ESP-32 board (search B08BTWJGFX on Amazon) which I thought would be a better bet because it does not have any onboard LEDs to complicate matters.
  • This e-paper driver board which I thought would be a surefire thing to work. However, I cannot connect it as-is to my e-Paper module. It comes with the ESP32 driver board, an FFC cable, and an "e-Paper adapter", but no way to connect to my e-Paper module. I can't find a corresponding cable for sale anywhere and I am now not sure if it is in fact compatible with my e-Paper module.

Please can somebody who understands this better give me some help.

  1. Can my e-Paper module be connected to the e-Paper driver board? If so, what components do I need to connect it?
  2. Has anybody had any success with either of the specific ESP-32 boards I mention and a Waveshare e-Paper module? If so, to which pins did you connect the coloured wires, and do you have a code sample? I have used many, many combinations of colour to pins, as suggested on various forums and git repos. I have tried many different code examples, mainly from that GxEPD2 github project.

I am a senior developer at a software company and usually pretty good at "figuring things out", but this has me beat!

Ultimately I want to make an image appear on the e-Paper module every so often, but at this point I would settle for "Hello World" or even a single pixel.

Separately, I am also having difficulty reliably flashing to my ESP-32 boards from my macbook. Usually it works a couple of times, but then the Mac cannot find the serial connection to the board.

Any help appreciated.

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Posting a link to the data sheet of that e-Paper device might make helpers interested.....

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Not sure what that is, the device is as described here: https://www.waveshare.com/wiki/4.2inch_e-Paper_Module

I realise now there is a Displays forum which I should have posted in, if anyone can help me move it, that would be great.

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Somehow there's a possibility to ask moderator to move the topic. Sadly I haven't found and used it yet.

I found this at the bottom of Your link. Have You tried that support?

Support

If you require technical support, please go to the Support page and post a tickets.

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Moved to Displays category and duplicate topic deleted

You just flag the topic as "Something Else" and ask for it to be moved

1 Like
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Google "Datasheet".... They contain all technical data about the device. Often they provide application examples.

1 Like
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@funkybro, Hi, welcome to the forum!

Thank you for providing links to your devices in question. This helps for providing answers.

I assume you have already read How to get the best out of this forum.
But I regularly post that link to my first answer to new posters.

Just to make sure, this black/white 400x300, 4.2inch E-Ink display module is your display? And you got it complete with the colored connection cable.

Unfortunately I can't help you with your Heltec OLED module yet; this has been asked before, and I bought one, but I didn't try and solve its use with e-paper displays yet. I think they use non-standard SPI pins. I will try when I am less busy.

Your Universal e-Paper Raw Panel Driver Board, ESP32 WiFi / Bluetooth Wireless should work with the suggested wiring for ESP32 with GxEPD2. Just remove the flat cable from the driver board, and connect the colored wires to the appropriate processor pin. Check the connections, there may be bad DuPont connectors, and push the white connector firmly in.
See README.md for use of shortened reset pulse most likely needed for this board.
Use e.g. a board like WEMOS LOLIN32 to compile for, as ESP32 Devkit may cause hang on Serial.begin().

If you ever want to use the driver board additionally connected to a raw panel with the flex cable, you would need to use a different wiring, as the flex connector doesn't use the standard HW SPI pins. See example GxEPD2_WS_ESP32_Driver.ino

Jean-Marc

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Thanks for this helpful information. I was able to flash my board a couple of times (with no success but I think I may know what I did wrong). But now I cannot flash from my mac any more, it's failing to find my serial port :frowning:

What does this mean:

See README.md for use of shortened reset pulse most likely needed for this board.

I looked at README.md in GxEPD2 and it just said

note that Waveshare bords with "clever" reset circuit may need shortened reset pulse

without explaining what a "shortened reset pulse" is.

Thanks.

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Just read on:

  • note that Waveshare bords with "clever" reset circuit may need shortened reset pulse
  • use init(115200, true, 2, false) for Waveshare boards with "clever" reset circuit
  • note that Waveshare bords with "clever" reset circuit need 1k pull-up on RST on ESP8266, or different pin

A reset pulse of 2ms (instead of default 20ms) may keep power to the controller because of some capacitors. For details look at the schematics.

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Regarding flashing your ESP-32 boards, I often have to unplug then re-plugin an ESP-32 for my Win10 PC to recognize it again. Further, I now use a powered USB extension cable or a powered USB hub for my ESP-32 USB connections as some of the 30 +/- ESP-32's I've worked with recently appear more sensitive to the quality of the USB supplied power.

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