Introduction: Smart Watch Using SNTP

About: I am SoC engineer^^

A smart watch becomes the most significant item in a wearable device category.

I did use the mbed web complier. I wish you use the mbed web complier.

A plan was as below.

- WIZwiki-W7500 + OLED + bluetooth + android phone

but..... time value is wrong data (obtained data from smart phone)

On second thought, I changed my plan.

- WIZwiki-W7500 + OLED + Ethernet + NTPserver

system operation
1. when Initial status operate, network time obtain from NTP Server
2. After that, the time count using RTC in mcu
3. After a few second, it change from yy/mm/dd h/m/s of small size to h/m of big size
4. when button connected to D3 pushit change from h/m of big size to yy/mm/dd h/m/s of small size

Step 1: Parts

- WIZwiki-W7500 at WIZnet : WIZwiki-W7500

- OLED 128x64(SSD1306/i2c) at Adafruit :

- Easy module Shield at YWRobot(only china site) : YWRobot

- Jumper cable : connect OLED and easy module Shield


- SSD1306 Driver

- Ethernet library (made in WIZnet)


- mbed web complier : LINK

Step 2: Hardware

WIZwiki-W7500 OLED

Step 3: Realize the Smart Clock

1. The Network time obtain from NTP Server using SNTP Protocol

2. The initial value of RTC write the bring data.

3. The Clock count using setting value.

NTP Server address is " ",and port is 40. but it appear Korea,Republic of of timezone

Step 4: Code

This code base on mbed(C++). but you can use the SSD1306.h file(c)

SSD1306.h file use like SSD1306 Library.


when rtc stored data store obtained ntp time, you have to calculate the ntptime(month) -1 and ntptime(year) - 1900

Step 5: Mbed Web Complier and CMSIS-DAP

You can download the firmware using the mbed web complie.

1. When you connect the USB cable to the WIZwiki-W7500, PC recognized as a removable disk. Removable disk name is MBED.
2. You “drag and drop” or copy the firmware to the removable disk, the firmware writing progress has completed.

3. After completing the firmware writing, open to check the removable disk.

4. If “fail.txt” file is exists in the removable disk, it means writing the firmware has failed.

5. After pressing the Reset button (SW1) of WIZwiki- W7500, please repeat the steps from 2.

Step 6: Design the Case of Clock

3D print : LINK

Step 7: Confirm the Operation

Step 8: Source Code and Reference Site

- smart watch source code : LINK

- ethernet source code : LINK

- 3D print : LINK