The CD4017 Decade Logic Clock Soldering Kit, Black PCB

Description

This is the The CD4017 Decade Logic Clock Soldering Kit from Kickstarter.

I’ve always wanted to make a binary clock that kept time with digital logic chips and displayed the time with 5mm LED’s. Until now, such a thing did not exist, so I created my own.

How it works:

The 4017 Logic clock is a clock unlike any other. You may assume that such a clock must use a micro controller. That would be cheating! This clock uses 4000 series digital logic IC’s from start to finish.

It all starts with a 32.768khz crystal oscillator. The oscillator circuit feeds into a CD4060 14 stage binary ripple counter. This counter divides the output from the crystal by two 14 times and outputs a 2hz square wave. The 2hz square wave is still too fast, so it is fed into a CD4027BE JK Flip-Flop. The flip flop divides the 2hz square wave into a 1hz square wave that is fed into the first CD4017BE decade counter, the seconds 1’s. This decade counter counts up from 0 to 9, then advances the next stage, the seconds 10’s. This count repeats until the seconds 10’s reaches a count of 6, and it is instantly reset to zero while simultaneously advancing the minutes 1’s digit. The minutes count up to 60 exactly the same as the seconds, resting to zero at 60 while simultaneously advancing the hours 1’s. The hours 1’s count up to 9, then advance the hours 10’s. The hours 10’s advance to 1 or 2, 1 in 12 hour mode, 2 in 24 hour mode. After this, a CD4082 dual 2 input AND gate detects when the count has reached 13 or 25, and resets the hours count to 1.

12 or 24 hour time

You can choose 12 or 24 hour mode with one flip of a switch. The CD4082 is a dual 4 input AND gate. One set of AND gates resets the hours at 13 and the other resets at 25.

What you will get and what you’ll need:

The soldering kit comes with everything you need to assemble your own 4017 decade clock including a PCB, components, hardware, a back cover plate and  LED’s. You’ll need a soldering iron and solder. You’ll also need to provide a USB cable. The clock will work with Micro USB or USB-B. You will need a base to hold the clock upright. You can 3d print your own or purchase one from the Bolt Industries store. You can find the STL file HERE.

How it’s assembled

The top PCB holds all the components and all the traces. The back of a soldered PCB is sharp and pokey, so the clock includes a cover plate that gives the clock a nice clean look while covering up the solder pads. The back cover plate also includes the component legend to streamline assembly. The kit includes a USB-B plug that fits nicely into the back plate, as well as a micro USB plug that points out the back. You can choose which connector to solder onto the board.

How accurately does it keep time? 

About as well as a digital wristwatch.

This clock uses a 32.768Khz crystal time source. It is does not get a time stamp from the internet, so it does drift from the actual time ever so slightly. You may have to set the time every month or two.

Assembly Required

The 4017 Logic clock is available as a soldering kit only. Assembly is required. It’s not a very difficult PCB to solder, but there is quite a few solder pads. Detailed assembly instructions are on the Bolt Industries web sight: www.boltind.com

Open Source

I’ve open sourced the projects schematic. If you’d like to make your own version of the clock or build it on a breadboard, take a look at my Hackaday project:

https://hackaday.io/project/177594-4017-decade-binary-clock