Seven color e-paper photo frame

Battery operated photo frame using the Advanced Color ePaper (ACeP™) display from Waveshare. The display has seven colors and measure 5.56 inch, 600 by 448 pixels. Overall dimensions: 125.4 x 99.5 x 9mm (WxHxD, depth includes header and display). Display usable area dimensions: 114.9 x 85.8mm (WxH). The images are preprocessed using Floyd-Steinberg dithering to reduce to 7 colors and still have a reasonable quality and stored on a SD-card. An Arduino is used to read from the SD-card and write to the display. lenna.bmp is a ready to use example image.

BOM

• 7 Color ePaper display
• Arduino pro-mini
• SD card reader (images storage)
• LDR (to not change the image in the dark)
• N-channel MOS FET (for example AO3402) (to switch off the SD card reader)
• 2x AA of 2x AAA battery holder
• 3.3 volt mini boost converter (power supply)
• Capacitor 220uF or bigger (power supply filter)
• Capacitor 100nF (power supply filter)
• 3D printed frame

To make the Adruino and SD card reader low power, remove the voltage regulator.

Wire up the Display, and SD-card reader to the Arduino (Uno / Nano / Pro-Mini)

Pins Arduino <=> SD Card module

• 10 - CS / SS
• 11 - MOSI / DI
• 12 - MISO / DO
• 13 - SCK / CLK
• GND - GND
• Vcc - 3.3V

Pins Arduino <=> 7 color e-paper display

• 7 - BUSY
• 8 - RST
• 9 - DC
• 6 - CS
• 13 - CLK
• 11 - DIN
• GND - GND
• Vcc - 3.3V

Prepare the images using Gimp

Start GIMP and drag the image to be processed into the application.

Create a seven color palette

Use the palette editor to create a seven color palette

	Color	Bin	Hex	R,G,B
1.	Black	0b000	0x0	0,0,0
2.	White	0b001	0x1	255,255,255
3.	Green	0b010	0x2	0,255,0
4.	Blue	0b011	0x3	0,0,255
5.	Red	0b100	0x4	255,0,0
6.	Yellow	0b101	0x5	255,255,0
7.	Orange	0b110	0x6	255,128,0

GIMP Palatte Editor dialog

Rearrange the colormap

Make sure that the colors are arranged in the correct order in the Rearrange Colormap dialog.
Main menu or right click image and select

• Colors >
• Map >
• Rearrange Colormap...
• Make sure the colors are ordered as mentioned above in the color palette or the image below, and select OK

Rearrange Colormap dialog

Resize and crop

Resize to 600 width or 448 height so an 600 by 448 image can be cropped.

Resize

Main menu / right click image and select

• Image >
• Scale Image...
• Provide width and or height
• Select Scale to apply the selection

Crop

'Shift + C' or main menu / right click image and select

• Tools >
• Transform Tools >
• Crop (Shift + C)
• Use mouse and or size and position fields
• Select Enter to apply the crop or Esc to leave the Crop menu

Dither

Main menu / right click image and select

• Image >
• Mode >
• Indexed...
• Use custom pallete
• Select the created 7 color palette
• Select Floyd-Steinberg for Color dithering
• Select Convert

Export as BMP

'Shift + Ctrl + E' or main menu / right click image and select

• File
• Export as (Shift + Ctrl + E)
• Type a filename and give it the bmp extension
• Deselect 'run-length encoding'
• Under 'Compatibility options' select 'Do not write color space information'
• Select Export

GIMP Export Image as BMP dialog