An Improved LEGO Dot Matrix Printer
Josh Renaud revamped his four-year-old LEGO Mindstorms EV3-controlled Viper Printer for better performance.
In 2017, Josh Renaud constructed a LEGO dot matrix printer called the Viper Printer, which printed out pictures using paper-advance wheels, an overhead track system, and a two-wheel pen lifting mechanism. While it worked fine – and was impressive for what it was – such a project is never really finished it seems. He decided to revisit the Viper Printer and do a total redesign for 2021.
His new device features a geared system for more consistent paper pulling, and instead of an overhead tank track mechanism to actuate the pen’s y-axis, it now uses a rack and pinion design. This combination allows it to get the dots in just the right places, for images that are definitely pixilated but much more accurate than before.
The pen lifting mechanism was also redesigned, using a LEGO linkage system rather than the two-wheel mechanism employed before. Although bulkier than Renaud would have preferred, it appears to work quite well in the demo.
The Viper Printer is controlled via a Mindstorms EV3 Brick, and the program is improved, yet fairly similar to the first iteration. You can see the two versions in action in the videos below, starting with the latest. Both are impressive, but it’s easy to see how much better the system became after rethinking the design!