Niklas Roy's Interactive Window Display Is Positively Awesome!

Niklas Roy’s workshop is located in an old shopfront in Berlin, and as people pass by every day headed to a beautiful park around the corner, he thought it would be nice to cheer them up with a positive message. Roy, however, had no clue as to what comment to put up, so he instead provided messaging infrastructure via a pen plotter in his window, allowing people to make up whatever they want.

The mechanical heart of this build is an old A3 pen plotter, which was given to him by a friend years ago. While the plotter mechanism was still intact — and looks like a beautifully solid piece of engineering — after years in storage, the electronics were not. These were replaced with an Arduino Mega, along with driver modules for the x and y steppers. A transistor was also added to take care of the pen-down solenoid. According to Roy's project writeup, “A few test drawings later, the plotter was alive again!”

For user interface, Roy added a NodeMCU ESP8266 board. This hosts a web server that passersby can log onto and send encouraging words that are then printed out on the paper in blocky text. The assembly is held on a wooden frame, with a large roll of paper on the bottom that is pulled up for printing and display. While it wouldn’t normally be notable, it does look reminiscent of a giant toilet paper roll, which certainly makes it even more eye-catching these days!