Tri-Color E-Paper Display: Red, Black & White ESP32 Project

Tri-Color E-Paper Display: Red, Black & White ESP32 Project

A tri-color e-paper display with ESP32 combining red, black, and white is one of the most striking display technologies available to hobbyists in India today. Unlike regular LCD or OLED screens, e-paper (also called e-ink) displays retain their image with zero power consumption — perfect for battery-powered IoT devices, smart labels, digital noticeboards, and indoor dashboards. In this guide, we cover everything Indian makers need to know to get a tri-color e-paper display working with an ESP32, from wiring and libraries to complete project ideas.

What is a Tri-Color E-Paper Display?

E-paper displays (electronic paper or e-ink) use millions of microcapsules containing charged black and white particles suspended in a fluid. Applying a voltage moves the particles to the top or bottom, creating black or white pixels. The image persists even after power is removed — similar to how ink on paper stays.

Tri-color e-paper adds a red layer to the standard black-and-white e-ink panel. This allows three colors — red, black, and white — to be displayed simultaneously. The red pixels are typically a separate layer that takes longer to update than the black/white layer, which is why tri-color refresh cycles are slower (typically 15–20 seconds vs 2–5 seconds for monochrome e-paper).

The key advantages of tri-color e-paper for Indian maker projects:

• Ultra-low power: Draws current only during refresh. A coin cell can power a static display for months.
• High visibility: Excellent contrast in bright sunlight — far better than any LCD or OLED.
• Eye-friendly: Reflective display, no backlight, zero flicker.
• Striking visuals: The red-black-white palette looks professional and clean for labels, badges, and dashboards.

Why Use ESP32 with E-Paper?

The ESP32 is the perfect microcontroller for tri-color e-paper projects in India because it combines WiFi connectivity, Bluetooth, low-power deep sleep modes, and enough RAM to handle e-paper image buffers. Key reasons:

• Deep Sleep: ESP32 can sleep between display updates, consuming as little as 10–20µA. Combined with e-paper’s zero-power image retention, you get extremely long battery life.
• WiFi: Download fresh content (news headlines, weather, stock prices) from the internet before each display update.
• SPI Speed: ESP32’s hardware SPI runs at up to 80 MHz, which speeds up the display refresh process.
• Memory: 320KB SRAM is enough to hold a full e-paper image buffer (e.g., 2.13″ at 250×122 requires about 30KB for each color layer).

Components Required

• ESP32 Development Board (any 38-pin or 30-pin variant)
• Tri-color E-Paper Display module (2.13″, 2.9″, or 4.2″ with SPI interface — red/black/white)
• Jumper wires
• USB cable for programming
• Optional: LiPo battery + TP4056 charging module for portable builds

Waveshare 2.13-Inch E-Ink Paper Display HAT — Three-Color (Red/Black/White)

A 250×122 pixel tri-color e-paper display from Waveshare. Works via SPI and is directly supported by the GxEPD2 and epd2in13b libraries. HAT form factor also fits Raspberry Pi.

View on Zbotic

Waveshare 2.9-Inch E-Ink Paper Display Module with SPI Interface

A 296×128 e-paper display with SPI interface. Compact, low-power, and compatible with ESP32. Great for digital name badges and shelf labels.

View on Zbotic

Wiring: Connecting E-Paper to ESP32

Tri-color e-paper modules use SPI with these typical pins (verify with your specific module’s datasheet):

Important: E-paper displays are strictly 3.3V. Connecting 5V will permanently damage the display. Use a 3.3V ESP32 board — do not use 5V Arduino directly without a level shifter.

Libraries and Setup in Arduino IDE

The best Arduino library for Waveshare and other e-paper displays is GxEPD2 by Jean-Marc Zingg. Install it via Library Manager:

1. Open Arduino IDE → Sketch → Include Library → Manage Libraries
2. Search for GxEPD2 and install it
3. Also install Adafruit GFX Library (required by GxEPD2)
4. In the ESP32 board manager, ensure you have the ESP32 core installed (by Espressif Systems)

GxEPD2 supports dozens of Waveshare displays. For the 2.13″ tri-color (red/black/white), look for the class GxEPD2_213_B73 or similar in the GxEPD2 documentation and match it to your module’s model number.

Sample Code: Drawing Red, Black & White

This example draws a red banner, black text, and white background — the classic tri-color e-paper palette:

#include <GxEPD2_3C.h>
#include <Fonts/FreeMonoBold9pt7b.h>

// For Waveshare 2.13" tri-color (red/black/white)
#define EPD_CS   15
#define EPD_DC   27
#define EPD_RST  26
#define EPD_BUSY 25

GxEPD2_3C<GxEPD2_213_B73, GxEPD2_213_B73::HEIGHT>
  display(GxEPD2_213_B73(EPD_CS, EPD_DC, EPD_RST, EPD_BUSY));

void setup() {
  Serial.begin(115200);
  display.init(115200);
  display.setRotation(1);
  display.setFont(&FreeMonoBold9pt7b);
  
  display.setFullWindow();
  display.firstPage();
  do {
    // Fill background white
    display.fillScreen(GxEPD_WHITE);
    
    // Draw a red header bar
    display.fillRect(0, 0, display.width(), 30, GxEPD_RED);
    
    // White text on red bar
    display.setTextColor(GxEPD_WHITE);
    display.setCursor(5, 20);
    display.print("ZBOTIC.IN");
    
    // Black text on white
    display.setTextColor(GxEPD_BLACK);
    display.setCursor(5, 55);
    display.print("Hello India!");
    display.setCursor(5, 75);
    display.print("E-Paper Demo");
    
    // Draw a red rectangle border
    display.drawRect(2, 35, display.width()-4,
                     display.height()-38, GxEPD_RED);
  } while (display.nextPage());
  
  Serial.println("Done! Display updated.");
  // Put display to sleep (saves power)
  display.hibernate();
}

void loop() {
  // Use deep sleep for battery-powered builds
  esp_deep_sleep(30 * 1000000ULL); // Sleep 30 seconds
}

The display.hibernate() call puts the e-paper into its low-power state. Combined with ESP32’s deep sleep, this configuration can run for weeks on a single 18650 battery if updates happen infrequently.

Project Ideas for Indian Makers

Here are practical tri-color e-paper projects well-suited to Indian conditions:

• WiFi Weather Dashboard: Fetch weather data from OpenWeatherMap API for your city (Mumbai, Delhi, Bengaluru) and display temperature, humidity, and a weather icon in red/black/white on the e-paper. Update every 15 minutes.
• Smart Price Tag: For small retail shops — show product name, MRP, and offer price. Use the red color for prices and offers. Battery-powered, no wiring needed.
• Digital Name Badge: Program your name, designation, and QR code onto a wearable e-paper badge. Lasts days on a coin cell battery.
• Library Book Label: Display book title, author, and Dewey number. Update wirelessly when books are moved.
• Power Outage Clock: An RTC-based clock that shows time even during power cuts — the e-paper retains the last displayed time indefinitely.

Waveshare 1.54-Inch E-Ink Paper Display Module with SPI Interface

A compact 200×200 pixel e-paper display. Great for wearable badges and small IoT devices. Supported by GxEPD2 library for easy ESP32 integration.

View on Zbotic

Waveshare 3.5-Inch E-Paper Display — Red/Yellow/Black/White (G)

A 4-color e-paper display (red, yellow, black, white) at 384×184 resolution. Perfect for eye-catching dashboards and retail signage projects.

View on Zbotic

Tips and Limitations for Tri-Color E-Paper

• Slow refresh: Tri-color displays take 15–20 seconds to fully refresh. This is normal — do not try to animate them. Plan for infrequent, meaningful updates only.
• No grey shades: Standard tri-color e-paper supports only red, black, and white — no grey levels. If you need greyscale, choose a dedicated greyscale e-paper (4-level or 16-level).
• Temperature sensitivity: E-paper refresh behavior changes significantly below 0°C and above 40°C. For Indian summer conditions (above 45°C), keep the display out of direct sunlight.
• Ghosting: If the same image stays for very long periods, slight ghosting may occur. Run a full white refresh cycle periodically.
• Power during refresh only: Connect a capacitor (100µF) across power supply to handle the current spike during display refresh, especially in battery-powered designs.

Frequently Asked Questions

Does the tri-color e-paper display work with Arduino Uno?

Yes, but with limitations. Arduino Uno has only 2KB SRAM, which is not enough to hold a full-screen buffer for most e-paper displays. ESP32 with 320KB SRAM is highly recommended. If you must use Arduino, use an Arduino Mega or pair an Uno with an external SRAM chip.

How long does a battery last with an ESP32 and tri-color e-paper?

With ESP32 deep sleep between updates, a 1000mAh LiPo battery can power the display for several weeks if updates happen once per hour. If updates happen once per day, battery life can extend to months. The e-paper itself consumes zero power between refreshes.

Can I display images (bitmaps) on tri-color e-paper with ESP32?

Yes. Convert your image to a 1-bit BMP or use an online tool like Waveshare’s image converter to generate C arrays. The GxEPD2 library supports bitmap rendering with drawBitmap() for both black and red layers separately.

What is the difference between the Waveshare tri-color HAT and a raw e-paper module?

The HAT format has a 40-pin GPIO connector for direct Raspberry Pi attachment. Raw modules have individual breakout pins for SPI connection to any microcontroller including ESP32. Both work with ESP32; the HAT just needs jumper wires instead of direct connection.

Is tri-color e-paper suitable for outdoor use in India?

E-paper has excellent sunlight readability — far better than any backlit display. However, the display itself is not weatherproof. For outdoor Indian conditions, house it in a sealed, UV-resistant enclosure. Avoid direct sunlight above 40°C which can degrade performance.