The PyroGraph is a experimental plotter which uses a soldering iron to burn images onto paper.


What have you made?

Inspired by the traditional thermal printers used for receipts in all shops, the PyroGraph analyses any image as input and converts it into dots by an image processing algorithm. These dots are then burned with a 450 °C tip onto paper. The time of contact between the iron and the paper determines the grayscale of the dot; the longer it presses against the paper, the darker the dots get. The machine uses a paper roll and a printhead moving on a fixed x axis, controlled by motors and software developed by the team.

What gave you the initial inspiration?

In the electronics lab of CIID (Copenhagen Institute of Interaction Design) where we study, we were looking for a way to print receipts with a thermal printer. We found the sparkfun thermal printer “COM-10438” that we could connect to an arduino. While playing with it, we got more interested in how it actually works and started doing some research on the technology. The fact that it was printing with heat made us think: “we could make our own printer”. Since the thermal printers use special chemical paper that reacts to low heat, we had to find something that could provide more heat and burn into normal paper. The obvious choice seemed to take apart a soldering iron, in such way that the iron had a flat surface. After manually placing the tip on different materials the idea was clear and we had to build it! From here and out we named it “The Pyrograph".

What is the original idea behind this project?

The original idea was to build our own version of a thermal printer that would use normal paper just for the fun of it. In the middle of the project we got the chance to exhibit at Trailerpark Festival in Copenhagen. So we decided to create a more robust and safe construction. The new version became bigger, wider and was designed to hang from the ceiling.

How does it work?

The build is very similar to a household printer. We have a x-axis that moves the print-head back and forth, a y-axis that pushes the paper forward and the z-axis that moves the soldering up and down. The 2 stepper motors and 1 servo motor is controlled by an Arduino. A custom processing sketch takes an image file, and rasterizes it, and sends the position and brightness data to the arduino dot by dot. It is possible to modify the image while it is printing, so we could use live input such as sound to distort the image, based on the machine's environment.

How long did it take to make it real?

The build took approximately 2 weeks including late evenings. During these weeks we faced multiple challenges, such as calibrating the right timing for the burning of the dots, reverse every second row and optimising the overall speed, since it is not the fastest printer to look at.

How did you build it?

We used a laser cutter to create the sides and holders for all the parts. Building the prototypes addressed one problem at the time so we could iterate fast and slowly add complexity to the build. The mechanical part consists mainly of linear and circular bearings, metal rods and stepper motors. For the electronics we used an Arduino Uno with a motor-shield attached to control the two steppers and the servo motor. A Raspberry Pi replaces a laptop on exhibitions to run processing which sends the rasterized image to the Arduino Uno.