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 with… ...

NTP Alarm Clock A few weeks ago I’ve built my own alarm clock. For that purpose I used an Arduino Ethernet and an Adafruit LCD Shield.

Using Arduino Nano 33 IoT or Particle Photon you can connect the clock via wifi to the NTP time server or cloud to synchronize time.