Project Description

This posting explains how to make the network watch with 7 segment. The watch will acquire the network time information using SNTP (Simple Network Time Protocol) and displays the current time on the 7 segment using RTC (Real Time Clock)

7 segment display is a form of electronic display device for displaying decimal numerals that is an alternative to the more complex dot matrix display. If you want to know more about 7 Segment, Click below link.

About 7 Segment (Wikipedia)

SNTP (Simple Network Time protocol) is the network protocol to synchronize the time on Internet. RTC provides the current time information. It counts the date, time, minute and second by operating independently from the MCU or CPU


  • WIZwiki-W7500 : 1EA (Cortex-M0 Platform board)
  • Common-Anode Type, Array 7 Segment : 2EA
  • BC547 : 8EA
  • Tact Switch : 1EA
  • 220Ohm Resistor : 16EA
  • 1kOhm Resistor : 8EA
  • 10kOhm Resistor : 1EA
  • 1uF : 1EA
  • Jumper Wires
  • Bread Board

Hardware Circuit



As you see above circuit image, the A~G pins from 7 segment are connected to WIZwiki-W7500 in parallel. Common pins can be optionally connected 3.3V using npn transistor.



As you see the demonstration movie, when the WIZwiki-W7500 is reset, it acquires the time information from NTP server. If the RED LED is on, it means the time information is successfully acquired from NTP server. The time information is registered to RTC. The current time of RTC is displayed on the 7 segment.

Whenever you press the switch, the time and data information is alternately displayed on the 7 segment.

Firmware Code

The firmware is programmed on the mbed on-line compiler. If you click below link, you can get the source code.