Hans DIY binary clock from scrap – “All the parts for this clock came from scrap. The red LED’s making up the display came from an old video player. The high brightness green LED was also from an old video player (a different one). The TTL logic chips were from old computer boards, with the possible exception of the 4518 counter chip, which was probably a left over spare from my Sidereal Clock project. The transformer came from an old audio cassette player.” [via] – Link.
DIY Binary clock