## IOT Technology Applied
You could also download the program from the following website:
## Step By Step Tutorial
* Connect the Distance Sensor to P14 (trig)/ P15 (echo) port of IoT:bit. * Extend the connection of OLED to the I2C connection port of IoT:bit. 
1.2 Programming (MakeCode)
**Step 1. Initialize OLED screen** * Drag Initialize OLED with width:128, height: 64 to on start. * Set distance1, distance2 and speed to 0 from variables. 
**Step 2. Set up function (calculate_Speed)** * Set up a new function calculate_Speed from Advanced > Functions. * Set distance1 to get distance unit cm trig P14 echo P15 (distance from the car to the distance sensor before 1 second) Drag Pause to wait 1000ms and set distance2 to get distance unit cm trig P14 echo P15 (distance from the car to the distance sensor after 1 second). * By the equation of speed = distance / time. We get the speed of the moving car to (distance1-distance2)/1 (unit: cm/s). 
**Step 3. Calculate car speed** * In block forever, call function calculate_Speed from Advanced > Functions to get the speed of the moving car. * Snap If statement into the loop. * Plot bar graph of … from Led and draw variable speed into the plotted value. Set value up to 20. * In if speed ≥0, snap clear OLED display from OLED to avoid overlap. * Snap show string and show value of variables distance1, distance2 and speed. 
Part 1 Solution:
MakeCode: [https://makecode.microbit.org/S08334-56214-27815-93357](https://makecode.microbit.org/S08334-56214-27815-93357)
You could also download the program from the following website:
Part 1 Result
It will keep checking the distance of cars from distance sensor by distance sensor in every 1s. The speed of the cars will be shown on OLED. A bar chart of speed will be shown on micro:bit LED also.
* Connect the Light Sensor to P0 port of IoT:bit. * Connect the Traffic LED Module to P12 port of IoT:bit. 
2.2 Programming (MakeCode)
**Step 1. Connect to WiFi** * 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. * Set variable oldmsg to “” from variables. 
**Step 2. Show icon “tick” and join channel after WiFi connection** * Snap show icon from basic to On WiFi connected and select icon tick. * Snap show string Device_ID. * Snap WiFi Receiver join channel from IoT:bit > channel. * Set channel to tsuenwan. 
**Step 3. Check traffic status** * Snap if statement to block forever * If WiFi is connected, * Create a new variable light2 and set light2 to light value from light sensor at P0. * Snap clear OLED display from OLED to avoid overlap. * Snap show string and show value of variables light2. * Pause 6000 (ms) to another checking. 
**Step 4. Send notification when someone pass by** * Snap if statement * Set light2 < 10 in to if-condition (traffic jam is detected) * Snap WiFi Sender send channel… message… from IoT:bit > channel * Set channel to tsuenwan, message trafficjam * Set else-condition (traffic jam is not detected) * Snap WiFi Sender send channel… message… from IoT:bit > channel * Set channel to tsuenwan, message nojam 
**Step 5. Receive WiFi message** * Snap On WiFi Receiver received. * Go to OLED, snap the clear OLED display to On WiFi received to avoid overlap. * Snap the show string. * Draw variable receivedMessage to show string placeholder. 
**Step 6. Set up a new function (TurnRed)** * Control traffic light at P12 green on from SmartCity > Output. * Pause for 2000ms from basic. * Control traffic light at P12 yellow on, pause for 2000ms. * Control traffic light at P12 red on and pause for 2000ms. 
**Step 7. Set up a new function (TurnGreen)** * Control traffic light at P1 red on from SmartCity > Output. * Pause for 2000ms from basic. * Control traffic light at P1 red and yellow on, pause for 2000ms. * Control traffic light at P1 green on and pause for 2000ms. 
**Step 8. Set traffic light default status** * Insert function TurnGreen to on start. 
**Step 9. Change traffic light status** * Snap if-statement, set received Message ≠ oldmsg to if-condition. * Set oldmsg = receivedMessage (renew the latest traffic status). * Snap another if-statement. * Set receivedMessage = trafficjam to if-condition. * Call function TurnRed. * Set receivedMessage = nojam to else-if-condition. * Call function TurnGreen. 
Part 2 Full Solution:
MakeCode: [https://makecode.microbit.org/S77055-47262-47956-56848](https://makecode.microbit.org/S77055-47262-47956-56848)
You could also download the program from the following website:
Part 2 Result
Light sensor is used to detect if there are traffic jam. Once the light intensity is not low, it indicates that there is a traffic jam on the road. Wi-Fi message “nojam” will be sent to another micro:bit (receiver).
Once the light intensity is too low, it indicates that there is a traffic jam on the road. Wi-Fi message “trafficjam” will be sent to another micro:bit (receiver).
* Connect the white LED Light to P13 port of IoT:bit. 
3.2 IOT Setup (IFTTT)
**For the setting of IFTTT, please refer to “Chapter 4: Cloud Control micro:bit by IFTTT”** **Step 1. Create applet in IFTTT** 
3.3 Programming (MakeCode)
**Step 1. 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. 
**Step 2. 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 P13. * Set variable WAN_Command = lightoff into else-if-condition. * Snap turn White LED … from SmartCity > Output, turn white LED with intensity: 0 at P13. 
Part 3 Full Solution:
MakeCode: [https://makecode.microbit.org/S35003-46585-93313-79082](https://makecode.microbit.org/S35003-46585-93313-79082)
You could also download the program from the following website:
Part 3 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.
* Connect the Motion Sensor to P1 port of IoT:bit. 
4.2 IOT Setup (IFTTT)
**For the setting of IFTTT, please refer to “Chapter 4: Cloud Control micro:bit by IFTTT”** **Step 1** * Go to https://ifttt.com , create applet (if webhooks then Email). 
**Step 2** * Go to “My services” > “Webhooks”, select “Documentation” . Copy your Webhooks Key as follows: 
4.3 Programming (MakeCode)
**Step 1. Show Device ID** * Get on button A+B pressed in Input. * Snap show string and snap Device ID. 
**Step 2. Show IFTTT Uploaded Status** * Get On IFTTT uploaded from IoT:Bit > IoT:Service. * Snap the clear OLED display to On WiFi received to avoid overlap. * Snap show string inside On IFTTT Uploaded * Draw the variable Status and Error_code to block show string 
**Step 3. Check motion sensor value** * Snap if statement to block forever. * If WiFi is connected, * If get motion (triggered or not) at Pin P1 = true then, that’s say someone is near the door. 
**Step 4. Send notification when someone pass by** * Snap if statement to block forever. * If WiFi is connected, * Snap Send IFTTT key… from IoT:bit > IoT Services, input your IFTTT key and input event name email2. * Snap show icon from basic and select a monster icon. * Snap Pause after if statement to the loop for 5 seconds delay for checking. 
Part 4 Full Solution:
MakeCode: [https://makecode.microbit.org/S04257-89623-17473-32946](https://makecode.microbit.org/S04257-89623-17473-32946)
You could also download the program from the following website:
Part 4 Result
When WiFi is connected, if there are any suspicious movement near the door, the buzzer will emit sound and an email will be sent to the house owner. Also, a monster icon will be shown on the micro:bit.
* Connect the 180ᵒ Servo to P2 port of IoT:bit. 
5.2 IOT Setup (App Inventor)
**For more details, please refer to “Chapter 3: Direct control micro:bit by App Inventor 2”** **Step 1. Create the page with the components** * On Designer: * Drag the components from the left menu – we will need buttons to open or close the door and a textbox for input the Device ID number. * Also, add the invisible component “Web” under connectivity, we will need it for WAN connection 
**Step 2. Make the programming part** * On Blocks: * The WAN control command URL is:http://control.smarthon.cc/publish?id=DeviceID&msg=ControlCommand * When Button1 is clicked, it will direct to the URL with given device ID and command “opendoor”. 
* When Button2 is clicked, it will direct to the URL with given device ID and command “closedoor”. 
* Download the App in your phone to by .apk or scan QR code. 
5.3 Programming (MakeCode)
**Step 1. Set servo initial position** * Snap Turn Servo to … degree from SmartCity > Output * Turn servo to 180 degree at pin P2 (the servo will control the door to be closed initially) 
**Step 2. Open/close door by WAN command** * If WAN command opendoor is received, turn servo to 45 degree at P2 (open door angle) *If WAN command closedoor is received, turn servo to 180 degree at P2 (close door angle) 
Part 5 Full Solution:
MakeCode: [https://makecode.microbit.org/16876-57308-88647-06271](https://makecode.microbit.org/16876-57308-88647-06271)
You could also download the program from the following website:
Part 5 Result
Input your device ID number in the textbox, then click button “opendoor” to send command “opendoor”. Click button “Close Door” to send command “closedoor”.
With app inventor and micro:bit, you can control the door open/close by mobile app!
