YouTuber turns a Raspberry Pi-powered truck into a giant printer

Many people love the Raspberry Pi (us included). Not only are the computing boards cheap, but you can do so much with them. Wild, wonderful projects spring up all the time with RPi boards as a central piece. The latest creation to catch our eye might just rank as one of the most astonishing: a truck transformed into a dot matrix printer.

As spotted by Tom’s Hardware, YouTuber Ryder Damen (who runs the channel Ryder Calm Down) uses a Raspberry Pi to control his homebrew “printer,” which involves a pickup truck, water, and a whole array of gear to spell out messages on the ground. Damen calls it “skywriting, but on the road.”

In the video, Damen explains how the idea came to be (watching trucks paint markers on the road), as well as the process of constructing the “printer” and the materials used. A plywood and a trailer hitch form the frame of the rig, with solenoids, valves, and hoses then mounted to the wood to serve as printer parts. The solenoids control the valves—when 12V current is applied to them, they open. Meanwhile, the hoses split the water flow from a central point (a pump and a bucket full of water) to each valve.

Controlling the setup is the Raspberry Pi, which is connected to each valve through a relay and the solenoids. Damen created a website on the device, on which you can type the message you want and choose the speed of the print job. (Damen comments in the video that you can also choose the font, but “only one font works.”) The message is then converted to an image, analyzed, and then divided into segments based on the number of valves on the truck. The code determines whether each valve is in an area considered light or dark: If dark, the valve spurts water. If light, valve stays off.

As part of the video, Damen shares some of the ups and downs of bringing the project to fruition, complete with all the troubleshooting involved at each stage of the process. (When it looked like the Raspberry Pi might have been killed off by the first relay used, I actually gasped in sympathy—as Damen notes, the Raspberry Pi has been hard to come by and replacing it would be difficult.) It’s a fun journey to follow, especially if you spent years around dot matrix printers.

If you happen to want to build your own road-writing truck, the code for the project is now available on GitHub—and the Raspberry Pi Foundation says supply will soon increase at long last, making it possible to get your hands on one again. But if that’s not your deal, Damen’s chronicles of other projects can entertain you instead. As Tom’s Hardware shares in its coverage of the dot matrix truck, you can also watch porch pirates get their comeuppance or build your own Christmas lights from Stranger Things.

Author: Alaina Yee, Senior Editor