Binary clock
A binary clock is – well, a clock. The only difference between a binary and a normal clock is that the binary clock displays the time in a binary code, not in regular numbers. (Abandoned and partly recycled in the Ultimate Alarm Clock)
Note: I abandoned this project and took it apart. Several parts of it now live on in my Ultimate Alarm Clock.
I’m building my own binary clock built around IC’s from the 4000-series.
Introduction
As I said before, the clock is based on IC’s from the 4000-series, namely the 4017 counter, the 4081 AND-gate and the 4518 BCD counter. My clock uses the mains frequency (50 Hz here) to determine the correct time. The 100 Hz pulse (after rectifying) is divided to 1 Hz using two 4017’s. This pulse is then fed to the 4518 counting the seconds. That 4518, in turn, produces a 1/60 Hz pulse (with the help of an AND-gate) which is fed to the minute counting 4518. As you probably already guessed, that 4518 produces a 1/3600 Hz pulse which is fed to the 4518 counting the hours. The output of each 4518 is directly shown with LEDs.
The circuit is my own design but that’s also the reason I don’t have a complete schematic yet as I only draw the important parts on some random piece of paper and keep the simple things in my head.
The following picture is a explanation on how to read a binary clock:
Project status
The clock is working. That is, it will start to count the time when the power is switched on. Adjusting the time can be done using three push button switches, each with a 470 pF capacitor across it for debouncing.
However, there are still being some problems that have to be solved. The first and most important is the transformer. I need a 4,5 V transformer with a power of 3,5 VA. Surprisingly, such a transformer proves very hard to find and I haven’t found it yet. I actually have a 4,5 V transformer, but it’s too small so when more LEDs on the clock are on its voltage drops significantly and the
clock stops counting. The second problem is that the debouncing of the switches doesn’t always work correctly. Probably that’s solved with a slightly larger capacitor, but I will wait with testing until I have a suitable transformer.
The project has been put to a halt until a suitable transformer has been acquired.
