Video magnifier

“[It’s a] technical version of a magnifying glass to help people with low vision,” Markus tells us. “It’s basically a camera that can be connected to any HDMI screen, with a simple interface to scale and modify images. There are lots of professional devices out there, and a few DIY takes on the category as well. My goal was to make it simple, portable and affordable. There’s also experimental support for reading out text.”

Markus came up with the idea when his grandmother was prescribed one of these professional devices after suffering from macular degeneration.

“Even though she generally shunned away from most technology beyond a telephone or TV, this improved her life a lot and she enjoyed reading and writing again, be it letters, books or the newspaper,” Markus says. “However, it’s a bulky device that was placed in the living room, so when she needed it for cooking recipes she had to frequently go back and forth between the kitchen and the living room.”

According to him, a DIY solution is at least a tenth of the price of professional versions.

Rapid prototyping

While a tablet or laptop would have done the job, the constant updates and unlock codes felt like a barrier. Raspberry Pi with a Camera Module and a screen seemed like the best solution to Markus.

“The software was relatively easy,” Markus explains. “But I experimented a lot with the form factor. I started out with a wooden setup as I wanted to make it look nice and non-technical, but my latest version is 3D-printed and I’m quite proud of its simple and portable design.”

There are three main functions for the magnifier: a button cycles through different magnification levels, while another can change colour modes. This includes inverting the colours or tinting it yellow or blue.

“There’s also an experimental readout feature,” says Markus. “[It takes] a picture and then uses Tesseract OCR to get the text which is later read out via the pico TTS library, all on-device without the need for an internet connection.”

Book smarts

“This has been an interesting project where I’ve learned a lot over the years,” Markus mentions. Everytime he revisits it he thinks about little tweaks he can make but is happy that the code is up on his GitHub so others can modify it to their needs.

Unfortunately Markus’ grandmother had a stroke before getting to test it, and is now unable to use it. However, other folks have been able to give feedback, much of it positive. He’s gone on to use Raspberry Pi and Camera Modules for other projects, such as a portable photo booth for weddings – sounds like something we need to cover in a future issue.