Despite the short timeframe over which Nyan Hat was designed and built, as surprising amount of thought was put into it's design, especially on the mechanical end of things. Nyan Hat features cam-actuated linkage plates, laser cut gears, and more acrylic and polycarbonate than any hat should have.
Nyan Hat is relatively simple electrically, at least compared to its mechanical bits. The 60 white LEDs that make up the stars are controlled by two two-transistor oscillators. Audio is provided by an old iPod Nano connected to the amplifier and driver from a stripped down set of computer speakers, and the entire hat is powered by a 9.9V, 2.3 Ah A123 lithium nanophosphate battery pack.