decora screen

Filling the empty void, or at least the space where my unused light switch used to be in the living room. I decided to yank it out and replace it with something more honest: an e-ink display embedded inside the switch box. Another screen in my life sounded like a good idea. Build first; provide purpose later.

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PARTS LIST

E-Ink ESP32
Waveshare 2.13inch E-ink Display
USB Type C Pigtail
3W AC/DC Module
3D Printing Service

FRUSTRATION 360

With the window shopping done, the first hurdle is designing the adapter plate. Turns out my switch cover style is Decora, which I learned counts as a standard. I was hoping I could find a pre-made blank to save me some time as I have very little experience with 3D modeling. And Glen Bayley to the rescue with his Decora blank insert. Now with some basic measurements from the waveshare display diagram I simply needed to cut a hole in the blank.

Back to the part where I have very little experience... I spent a few hours in fusion360 before uninstalling and almost calling it quits. I stumbled upon another tool called TinkerCAD, which I can only imagine was designed for young children to play with. Evidenced by the fact there is a minecraft mode for building your models. But for me this was good enough to put a hole in a plate. My struggle lives here.

ELECTROCUTING FOR BEGINNERS

To fit everything inside a light switch box, I needed to power the USB-C based ESP32 directly from the AC wires already in place. The hardware here uses very little amperage, so I picked the smallest AC/DC module I could find, helpfully sold on Amazon. A bit of soldering on the USB pigtail, a couple of junction wires on the other side, and it was ready to start a fire power up.

PUTTING IT TOGETHER

The only notes here is that I hot glued the waveshare screen into the adapter. Please check your National Electrical Code for proper installation.

UPLOADING MY DREAMS

I will spare you the scratched together code I am running on this abomination, but you will probably need some pointers to get the display working. This is the important part:

// Imports
#include <GxEPD2_BW.h>

// Pin reference
// CS 15
// DC 27
// RST 26
// BUSY 25

// Initialize display driver
GxEPD2_BW<GxEPD2_213_BN, GxEPD2_213_BN::HEIGHT> display(
    GxEPD2_213_BN(15, 27, 26, 25));

void initDisplay() {
  Serial.println("Starting display");
  display.init(115200);
  
  // SPI pin assignments
  SPI.end();
  SPI.begin(13, 12, 14, 15);
  
  // Set display defaults
  display.setRotation(0);
  display.setTextColor(GxEPD_BLACK);
  display.setTextSize(1);
  display.setFullWindow();
  display.firstPage();
  
  // Clear the display
  do {
    display.fillScreen(GxEPD_WHITE);
  } while (display.nextPage());
  
  Serial.println("Display cleaned");
}

Now what to do with this new power? A count down of remaining months in your average life (374)? Or maybe you can begin fetching data from your home assistant server, public apis or wherever. Some things that I thought would look cool and maybe partially useful is the weather outside, my total home energy usage, unlocked doors, and intruders; don't try it.

CONCLUSION

I hope this project inspires you to build something and distract you long enough to forget the quiet dread. Even if just for a second.