19. IoT Case 10: Smart Street Light

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19.1. Goal


Make a smart streetlight which can have a button to control on off.

19.2. Background


What is Smart Street Light?

To improve the living stand of citizen and to save electricity, smart street light can be automatically turned on at night (eg.6pm) and turned off in the morning (eg.6am)

Smart Streetlight operation

When WAN commands are received from WAN (eg. IFTTT), micro:bit will get the command name. If the command name is “light_on”, the LED light will be turned on. If the command name is “light_off”, the LED light will be turned off.

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19.3. Part List


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19.4. Assembly step


Step 1

Attach the LED light to the model I2 with M4 screw and nuts. Put together all the cardboard parts (I1-I3)

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Step 2

Assembly completed!

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19.5. Hardware connect


Connect the white LED Light to P1 port of IoT:bit

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19.6. Programming (MakeCode)


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

  • Snap Initialize OLED with width:128, height: 64 to on start

  • Snap Initialize IoT:bit TX P16 RX P8 from IoT:bit to on start

  • Snap Set Wi-Fi to ssid pwd from IoT:bit

  • Enter your Wi-Fi name and password. Here we set smarthon as SSID and 12345678 as password auto_fit

Step 2. Show icon “tick” after WiFi connection

  • Snap show icon from basic to On WiFi connected and select icon tick

  • Draw the Device ID variable from On WiFi connected to the show string block placeholder pic_60

Step 3. Receive WAN command

  • Go to OLED

  • Snap the clear OLED display to On WiFi received to avoid overlap

  • Snap the show string to On WiFi received

  • Draw the WAN_Command variable to show string placeholder pic_80

Step 4. Turn on/off LED by WAN command

  • Snap if-condition

  • Set variable WAN_Command = lighton into if-condition

  • turn White LED from SmartCity > Output, turn white LED with intensity: 1023 at P1

  • Set variable WAN_Command = lightoff into else-if-condition

  • Snap turn White LED from SmartCity > Output, turn white LED with intensity: 0 at P1 auto_fit

Full Solution

MakeCode: https://makecode.microbit.org/_2cRf6LWq69AL

You could also download the program from the following website:

19.7. IoT (IFTTT)


* For the setting of IFTTT, please refer to “Chapter 4: Cloud Control micro:bit by IFTTT”

Step 1. Create applet in IFTTT

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19.8. Result


The micro:bit is controlled by IFTTT (trigger by date&time). The LED light will be turned on at 6pm and turned off at 6am every day.

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19.9. Think


Q1. How to turn on the light automatically if the today’s weather is cloudy reported by IFTTT.