I’m not quite old enough to remember the CMOS 4000 series ICs being released. I do, however, have a massive fondness for the series as, some years ago, I fell into the heady world of “Lunetta” building. Lunetta builders, working in the vein of Stanley Lunetta, create noisy synths using only the CMOS 4000 series running at audio rates in a way that was never particularly intended. The fact that you can make 6 square wave oscillators from a single CD40106 still excites me and a close follow-up favourite was making lo-tech sequencers using the CD4017 decade counter. Nostalgia aside, the CD4017 is an excellent chip that allowed clock and counter devices to be made very simply, including many early digital timepieces. This excellent CD4017 Digital Logic Clock V2.0 kit allows you to learn about the CD4017 and also practice your surface mount soldering to build this attractive clock.
Supplied as a PCB and components you’ll need a fine-tipped soldering iron and some thin SMD solder around 0.4mm or less. If you have done some through hole soldering before and want to try surface mount then this is potentially a great project to learn with. Over on the product page, there is a link in the documentation section to a web page with numerous videos and guides on how to build this device. Another option is “drag soldering” using a flat-blade tip to “drag” the solder along the leads. There are some excellent videos online demonstrating all sorts of SMD techniques — be sure to check them out! It’s not nearly as hard as it’s made out to be.
The device combines 6 x CD4017 decade counters which allows it to have an LED display for hours, minutes and seconds. The timebase is built around a 32.768 kHz crystal, with a CD4060 and 4027 dividing that down by 214 resulting in a 2 Hz clock pulse. It’s built largely using the same type of technology as now vintage digital timepieces and, as such, should keep time well. Powered over USB, we can imagine this sitting on a desk or workbench as an excellent and attractive conversation starter.
