Waveshare E-paper Picture Frame

Table of Contents

• Introduction
• Knowledge Assumptions
• File List
• Specifications
• Parts List
• Other Equipment Needed
• Printing Instructions
• PCB Board Instructions
• Assembly Instructions
• Arduino Code
• Python Code
• SD Card
• Testing and Putting it Together
• Battery Life and Power Consumption
• Additional Resources

Introduction

This project displays an image on an e-paper picture frame. The picture switches once per day. Included are the list of materials and how to build it.

Knowledge Assumptions

I am assuming in this project that the user knows how to do the following:

• Read an electrical schematic.
• Basic soldering of through-hole components.
• Configure and build a project using the Arduino IDE.
• Slice a 3d Model and send it to a 3d printer.
• Put brass inserts into plastic using a soldering iron.
• Run a Python script.

File List

• Documentation
• Gerber files
• STL Files
• Freecad code
• Arduino IDE code
• Convert Images Script
• Sample SD Card Image

Specifications

• Display Size 5x7 inches or 10x18cm.
• Battery life should be about a year with alkaline batteries.

Parts List

Basic Parts

Fasteners

Electrical Parts

Note that all electronic parts are through-hole components. Note that many substitutes can be used for the resistors, capacitors, and diode.

We need a package of straight DuPont-style male row connectors in order to make the 1x2, 1x6, and 1x8 Connectors. Also (10Cm) short multicolor Dupont Female to Female wires.

Note that the Micro SD Card doesn't need much capacity. A 1Gb Micro SD Card should work.

Other Equipment Needed

Other Hardware Needed

• 3D Printer
• Soldering Iron
• Arduino FTDI USB to Serial 5v Programmers

Also, it is a good idea to have troubleshooting equipment such as a multimeter and something to decode the SPI bus traffic.

Software Needed

Need the software Arduino IDE to build and download the code. I used version 2.1.0, but the latest version probably would work for you.

Arduino IDE Packages

Python Environment

I used Python 3.9 with the Pillow (Python Image Library) 9.3.0 package installed. The latest of each should work.

Optional Software

Printing Instructions

Printer Settings

3D Printed Parts List

Part	Picture
Main Part
Battery Cover
SD Card Cover
Display HAT Cover
Main Board Cover
Frame Border

PCB Board Instructions

Gerber files are listed in the gerber directory. I used OshPark to create the PCBs, but you should be able to use other vendors.

Assembly Instructions

Insert the M2.5 Brass Inserts into the Following Holes

Use a solder gun to insert the brass inserts.

Insert the M2 Brass Inserts into the Following Holes

Solder Components to PCB Board

Solder components to the PCB board. The silkscreen shows the Component number location.

Assemble the Main Part to Frame

Remove the original back assembly from the picture frame. We do not need the back of the picture frame, the screws, or the stand. We only need the picture frame and the glass.

Mark Drill Holes. (See frame back picture) Drill holes into the picture frame using a 5/64 or 2mm drill bit.

Remove any stickers from the glass. Clean glass the glass using glass cleaner or isopropyl alcohol. Ensure that no fingerprints are on the inside glass.

Assemble in the following order:

1. Wooden Frame
2. Glass
3. 3D Printed Frame border
4. E-paper display (Be sure the protective covering is removed and the e-paper display ribbon cable is at the top.)
5. 3D Printed Main Body

Use the #4 wood screw holes to attach the 3D Printed main body to the wooden picture frame.

Put Boards into Main Picture Frame

Connect the Ribbon Cable to the E-Hat

The extension cable for the e-paper display is not needed. Connect the ribbon cable from the display to the e-hat. Use M2 roundhead screws to attach the e-hat.

Attach the Battery Case

Push battery wires through the holes in the main body. Attach the battery case using M2 Flathead screws.

Attach the Other Components to the Main Board

SD Card Adapter and Main Board used M2 Roundhead screws. Be sure that the hole in the main body for the SD Card matches the SD Card slot.

Attach the main PCB board. Ensure that the J3 screen is next to the hat connector and the SW1 is at the bottom of the display.

Make Connections to PCB Board

Attach the battery to J4. PCB board is marked red for positive and black for negative.

Attach SD card connections to J2. Chip select is closest to R1. Please double-check schematic.

Attach the Waveshare e-hat SPI connections to J3. Gray should match GRY on the board. Note that the BLK wire may be purple.

Arduino Code

Arduino Code Overview

I had to make a couple of changes to the Waveshare drivers. They are:

A. Changes with Waveshare drivers (SPI frequency and chips select) B. Reduced the SPI clock speed.

Download Instructions

Use Board type "Arduino Uno"

Attach FTDI USB to serial connector to J1 serial connector.

Enable Serial Debug

If you run into problems, you may want to enable serial debugging. To enable serial debug out, uncomment line 50.

// Include this flag to turn on serial logging.
// #define SERIAL_DEBUG

The last failure is saved in the EEPROM. When booting, the error code is outputted over the serial port. The error codes are listed in line 36 of debug.h.

#define ERRORCODE_TEST                        0
#define ERRORCODE_EPAPER_INIT_FAILED          0x101
.
.

Python Code

Preprocessing Portrait Images

Images that are formatted as portrait may need to be cropped so that faces and important details may be shown.

Python Command-line Arguments

	convert_images.py   

This command converts images from the source directory or its children into the destination directory.

Images in the destination directory are listed in the following order: pic_000.bmp, pic_001.bmp, pic_002.bmp, etc.

This program also does the following:

1. Auto-adjusts the contrast.
2. Increases the saturation so the images don't look washed out.
3. Mirrors the image to looks correct when viewed from the picture frame.
4. Crops the image so the image size is correct.
5. Dithers the images so that only seven colors are needed to display the image.
6. Randomizes the image's order.

SD Card

Sample SD Card Image

A sample SD Card image is located in:

Sample SDCard Image

SD Card Format and Files

The Micro SD Card capacity can be small since the images don't occupy much space. Format a Micro SD Card using Fat32. Copy the processed image files to the root of the Micro SD Card.

Insert the Micro SD Card into the Micro SDCard Adapter for Arduino.

Testing and Putting it Together

Verify that the image appears on the e-paper display.

Attach the 3D-printed covers.

Battery Life and Power Consumption

It takes about 134 seconds to change the image on the screen. During this time, it uses approximately 30mA.

$$ = 134 (seconds/switch) * 30 (mA) / 3600 (seconds/hour) $$

$$ = 1.1 (mAh/switch) $$

When idle, the current draw is about 50 uA.

$$ = 24 (hours) * 0.05 (mA) $$

$$ = 1.2 (mAh) $$

An approximate AAA battery life is about 1500mAh. Therefore, the battery life for the picture frame is:

$$ = 1500 mAh / 2.3 (mAh/ day) $$

$$ = 652 (days) $$

Additional Resources

Waveshare 7.3inch e-Paper HAT (F) Manual

e Paper with Arduino and Raspberry Pi

Trolling My Mom With an E-Paper Picture