12. IoT Case 09: Smart Digital Morning Clock¶

Level:

12.1. Goal¶

Make a digital clock that performs a normal clock function with auto-synchronizing Internet time, and alert at specific time.

12.2. Background¶

What is Smart Digital Clock?

Smart digital clock is a clock that shows time as accurate as to atomic clock by connecting to the Internet.

Smart Digital Clock Principle

NTP protocol ensures devices synchronize their time with an accurate time internet provider. With connecting to the Internet, the digital clock can show the time close to atomic clock in millisecond .

In the program, it will get the internet time every 0.5 second to show the time on the OLED. When the time is arrived to specific time (e.g. 06:00:00), it will turn on the alert. Otherwise, it will turn of the buzzer. When the user pressed the button A, the alarm can be closed.

12.3. Part List¶

12.4. Assembly step¶

Step 1

In this case, build the “Big Style Model” as a home base.

Step 2

Let’s build a bed room to install a digital clock. Put the model E3 onto cardboard A, align with the holes at model A and B3.

Step 3

Attach the OLED display as a digital clock to the model E3 using M2 * 10mm screws and nuts.

Step 4

Put the model E4 onto cardboard A, align with the holes at model A and B4.

Step 5

To build a bed. Put model J2 onto the model J1, then put together all the cardboard parts (J1-J3).

Step 6

The bed completed!

Step 7

Place the bed next to the digital clock at the room.

Step 8

Assembly Completed!

12.5. Hardware connect¶

Connect OLED to I2C port
Pull down the buzzer switch to connect the buzzer

12.6. Programming (MakeCode)¶

Step 1. Initialize OLED, IoT:bit and connect to WiFi, create the variable

Snap Initialize OLED with width 128, height 64 to on start
Snap Initialize IoT:bit TX P16 RX P8 to on start
Snap Set Wi-Fi to ssid pwd to on start and enter the SSID and password
Create the variable alarmTrig
Set the alarmTrig variable to false

Step 2. Check Wi-Fi connection state

Snap the On WiFi connected block to editor
Put a show icon tick inside the block to show tick icon after connected

Step 3. Get the NTP time

Put a if statement in Forever
Use WiFi connected? as condition
In if segment, put Get NTP Current Time at city HongKong(UTC+8) to get NTP time
Pause 500ms to get the NTP time with each 0.5 second