ePaper Polaroid

Instant pictures with a Raspberry Pi, a webcam and an ePaper display:

The boredom of a winter saturday was spent building this diy instant photography style device. By pressing the button, the webcam takes a picture, which is then cropped, resized and converted to black and white to be shown on the ePaper display.

Image processing

Here is an example of a captured webcam image and the images after each processing step. First, the original image from the webcam:

This is cropped to a square.

Then the image is resized to the display resolution of 200x200 pixels.

And the last step is to convert this image to a binary, black and white image.

And then visible on the display:

Code

There is very little code, all of which relies on great python libraries. Button presses are detected with the builtin Raspberry Pi GPIO library¹(see button.py). Capturing images from the webcam is done with openCV²(see capture.py). The image is then saved as a jpeg file and loaded with the Pillow image processing library and processed, as seen above. Then it is sent to the display over the SPI connection (see display.py).

The Raspberry Pi is run with a full Raspberry Pi OS image (headless image makes installing openCV harder because of the missing multimedia libraries) and the script ePaper_polaroid.py is started on every reboot via cron (https://phoenixnap.com/kb/crontab-reboot).

Hardware

• Raspberry Pi 4B
• Logitech C200
• Waveshare 1.54 inch e-Paper (https://www.waveshare.com/wiki/1.54inch_e-Paper_Module)
• Pushbutton

Footnotes

1. https://raspberrypihq.com/use-a-push-button-with-raspberry-pi-gpio/ ↩

2. https://www.jeremymorgan.com/tutorials/raspberry-pi/how-to-install-opencv-raspberry-pi/ ↩