Making a clock with a common microcontroller like an Arduino isn’t very difficult. However, if you’ve tried it, you probably discovered that keeping track of wall time is difficult without some external hardware. [Barzok] has a very minimal clock build. It takes a handful of LED arrays with an integrated driver, an Arduino Nano, a real-time clock module, and a voltage regulator.

The software uses a custom 6×9 font and handles addressing the LEDs as one single display. Because the real time clock module is so accurate, there’s no provision for setting the time. [Barzok] says that twice a year he just hooks the Arduino up and reflashes the program with a new start time and that seems to be sufficient.

It wouldn’t be too hard, though, to add a few buttons to allow for setting the time or accepting other user input. Then again, this is a minimal build. It would be a good starter project for someone looking to get into building microcontroller projects.

If you want really minimal, you could go with a 4 LED clock (but you better know the resistor color code). Of course, an ESP8266 can serve as a simple clock and it gets set via NTP which is even better.

If you haven’t jumped on the ESP8266 bandwagon yet, it might be a good time to get started. If you can program an Arduino you have pretty much all of the skills you’ll need to get an ESP8266 up and running. And, if you need a good idea for a project to build with one of these WiFi miracle chips, look no further than [Ben Buxton]’s dated, but awesome, NTP clock.

While the ESP8266 started out as an inexpensive, reliable way to get WiFi capability on essentially anything (and paving the way for a plethora of Internet of Things projects), it was quickly hacked to become a fully programmable development board that can stand on its own. To that end, [Ben] has recognized its capability to run a very minimalistic NTP clock. The standard C++/Arduino environment is available, so he didn’t have to learn any new skills. The parts list is stripped down as well: besides the ESP8266, there’s little more than the four-part seven-segment display. There’s even an Arudino library for these chips that [Ben] made great use of. From there, it’s just a matter of wiring it all up and syncing it with an NTP server.

While it’s not the most involved hack ever, it’s good to be reminded that these chips are cheap and readily available for literally anything that you could imagine. If you haven’t started yet, there’s no reason not to. You can use them to control something like an irrigation system, or if you’re even more adventurous, they can run a 3D printer, too.

Thanks [Itay] for the tip!