3D-Printed Document Scanner Captures Sharp Scans with a Raspberry Pi and Camera Module

This 3D-printed Python-powered document scanner captures anything in a single button push, saving to a USB stick.

Pseudonymous maker and cosplayer "Caelestis Cosplay" has built a custom document scanner, powered by a Raspberry Pi single-board computer (SBC) and a Raspberry Pi Camera Module V2 — all held together using a smart 3D-printable frame.

"The ability to digitize documents efficiently holds vast importance in today's digital-first environment, serving purposes ranging from personal archiving to reducing paper clutter and facilitating educational activities," Caelestis explains of the project's potential. "Assembling this scanner yourself not only provides a cost-effective alternative to commercial scanners but also enriches your understanding of hardware integration, software development, and advanced image processing."

This compact document scanner is powered by a Raspberry Pi 4 Model B running a Python script. (📹: Caelestis Cosplay)

The heart of the build is a Raspberry Pi 4 Model B single-board computer — and while other models should be supported by the software used, the 3D-printed framework that puts everything together would need to be modified accordingly.

The Raspberry Pi board's general-purpose input/output (GPIO) pins are connected to a single push-button switch, a piezoelectric buzzer, and a pair of LEDs — used to trigger a capture and to offer a screen-free status readout respectively — while a Raspberry Pi Camera Module V2 handles the actual document scanning work.

Unlike a traditional flatbed scanner, which uses a moving scanning head, Caelestis' scanner captures a full image in seconds using the Camera Module — positioned above whatever document is to be scanned on a 3D-printed overhead mount. On the software side, a Python script uses the PiCamera 2 library to capture images and then the imutils, numpy, and cv2 libraries to process them for automated perspective correction and cropping.

Caelestis' full guide is available on Instructables, along with the STL files for printing the framework to hold the Raspberry Pi and camera.

Gareth Halfacree
Freelance journalist, technical author, hacker, tinkerer, erstwhile sysadmin. For hire: freelance@halfacree.co.uk.
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