IoT Watch with Wiznet W7500
This article explains how to make a simple network watch with 7 segment LED display. The watch gets time information from network using SNTP (Simple Network Time Protocol) and displays the current time on the 7 segment display using RTC (Real Time Clock).
The good old 7-segment display was widely used at the end of last century. I’m sure you still have some in your desk drawer. It is a “low cost” alternative to matrix LED display.
SNTP (Simple Network Time protocol) is the network protocol for time synchronization on the 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: 1ks (Cortex-M0 Platform board)
• LED display Common-Anode Typ, 7-Segment : 2EA
• BC547 : 8EA
• Tact Switch : 1EA
• 220Ohm Resistor : 16EA
• 1kOhm Resistor : 8EA
• 10kOhm Resistor : 1EA
• 1uF : 1EA
• Jumper Wires
• Bread Board
As shown on the circuit image, the A~G pins from 7 segment display are parallely connected to WIZwiki-W7500. Common pins can be optionally connected 3.3V using npn transistor.
If you watch 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 LED display. Whenever you press the switch, the time and data information is alternately displayed on the display.
The firmware is programmed on the mbed on-line compiler. If you click on below link, you can get the source code.