Title: Explaining the Laser Printer
Time: 5 days
Tools: Arduino, 12 Motors, 12 Magnets, Illustrator, Laser Cutter, Modeling, Iron Files
Team: Chelsey Wickmark, Ciaran Duffy , Feild Craddock
Task: Explain Technology to a child
In the last decade Science Museums have been transitioning into Science
Centers. Instead of just looking at dusty dead animals and wooden
contraptions we are now experiencing interactive installations that help us
understand what technology is all about.
A small town north of Jutland want to open a Science Center, but has a limited
budget and wants to be able to make everything internally. The museum will be
a playful venue for kids and geeks.
Faculty: Alice Pintus & Lorenzo Romagnoli
How does a laser printer work? The final output of the two-week Physical Computing module was to design an installation for a children’s science museum explaining how something ‘technological’ works. Beginning with an interest in how things move from digital to physical formats, this project explains how a laser printer turns what we see on-screen, to words and images on a page.
Once the information has been sent to the printer, how does the ink actually go onto the page? What do the lasers do? How is the page rolled out? Understanding the principles of laser printing is no easy task for adults, let alone children. The important thing was to convey, generally, what happens inside of a printer in a way that would be memorable and tangible to children and adults alike.
The computer sends the document or image to the printer. The laser magnetises the area of the page where the text or image is to go. The ink is oppositely charged and will only go on the areas of the page that have been charged. These broad concepts are illustrated to children using this analog laser printer. They must complete each part of the process themselves; sending the information to the printer, charging the page, applying the ink. In doing so, the process of making something physical from something digital becomes clear and relatable.
At the beginning of the process we as a team discussed which aspect of technology we would be interested in prototyping an experience for children around. We very quickly decided to go for a laser printer, because it was important to us to explain something a child had interacted with before. We researched the technology and science behind the laser printer to then discuss what we would like the experience to be like and which part we want to focus on. The magic of how the ink knows where to go and how it can stay attached too the paper turned out to be our main explaination of the mechanism.
At the beginning of our process we tried building our own magnets by magnetizing iron nails through winding copper wire around the nails. The first experiments with the iron nails turned out to be very successful, so we attempted to scale it up and use electromagnetically charged iron nails in our prototype. Our success in small scale unfortunately did not work on a larger scale. First we ran into some power issues, because arduino could not provide enough power. As a next step, we added external power supplies, but it turned out, that the copper wire could not deal with the increase in electricity and started smoking.
For this reason we chose to explore a different mechanism: Magnets attached to servo motors.
We hooked up 13 servo motors to an arduino through a multiplexing chip. The idea was that the magnets would allow iron files to only stick to the paper when turned 180 degrees.
We created patterns for every letter and translated these patterns into our code. Whenever a button with a letter was pressed the corresponding motors turned their arms towards the board from the backside. After having the motors in position the iron files could be poured over the front sheet and would stick to the magnetised spots, visualising the requested letter.
I played a key role in the first prototyping iteration wiring up all the iron nails with copper wire attempting to create a magnetically charged grid, that would allow us to display letters through iron files.
After this first attempt failed another team member and myself were responsible for creating a new grid with servo motors and magnets attached to their arms as well as creating an on/off grid for the letters A-F in our Arduino code.