According to James Hobson of HackADay, the current prototype uses a sheet of plastic coated in thermochromic ink – curved on an MDF frame.
“To display digits, Davide created tiny segments of the 7-segment display by wrapping the nichrome wire around pieces of cardboard, which then have been glued to the back of the display,” Hobson explained.
Meanwhile, Davide noted that although the prototype shows a 7-digit display, the detailed build guide can be easily modded to create a small dot-matrix display.
“The working prototype uses a sheet material printed with thermochromic liquid crystal ink,” Davide wrote in an official Design News description.
“It changes color (bright blue) when heated above 27C. Nickel-chrome wire is used to heat the segments and everything is controlled by an Arduino Mega board.”
The DIY curved display was made with 4mm Mdf, cut with a CNC, although this can also be done by hand. In addition, Davide used a 24V DC power supply, converted to 20Vdc with a KIA7820A. A 1000uF capacitor reduces noise on the 24V line, while a 220uF reduces noise on the 20V line. Last, but certainly not least, the Atmel-based Arduino is USB powered from the PC.
Interested in learning more about building a DIY curved display with an Atmel-based Arduino Mega? You can check out HackADay’s coverage here, the Design News article here and a detailed build tutorial (PDF) here.