# IoT Case 09: Smart House door control Level: ![level](images/level4.png) ![auto_fit](images/Case9/case-09.png)

## Goal

Use app inventor to create an APP to control the door of the house.

## Background

What is app inventor?

App Inventor allows user to develop their own app for Android phones or IOS device(iphone, ipad) by simple programming and design work.

Smart House door operation

When the micro:bit receives the signal “opendoor” from the app, the 180o servo will turn for 180o to open the door. When the micro:bit receives the signal “closedoor” from the app, the 180o servo will turn back 180o to close the door.

![auto_fit](images/Case9/Concept-diagram-Case9.png)

## Part List

![auto_fit](images/Case9/case9_parts.png)

## Assembly step

Step 1

Attach the L-shaped stand with M3 screws and nuts to the model H1. Make a small hole to fix into the stand securely.

![auto_fit](images/Case9/Case9_ass1.png)

Step 2

Attach the servo to the model H1.

![auto_fit](images/Case9/Case9_ass2.png)

Step 3

Straighten the paper clip and cut it to 6.5 cm. Use pilers to fix the paper clip into the L-shaped stand.

![auto_fit](images/Case9/Case9_ass3.png)

Step 4

Put together all the cardboard parts (H1-H2)

![auto_fit](images/Case9/Case9_ass4.png)

Step 5

Assembly completed!

![pic_50](images/Case9/Case9_ass5.png)

## Hardware connect

Connect the 180ᵒ servo to P2 port of IoT:bit

Micro:bit P2|Servo -:-|-:- S (yellow)|S (orange) V (red)|V (red) G (black)|G (brown) ![auto_fit](images/Case9/Case9_hardware.png)

## 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` ![pic_60](images/Case9/Case9_p1.png)

Step 2. 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) ![pic_60](images/Case9/Case9_p2.png)

Step 3. 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](images/Case9/Case9_p3.png)

Step 4. 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](images/Case9/Case9_p4.png)

Step 5. 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) ![pic_80](images/Case9/Case9_p5.png)

Full Solution

MakeCode:https://makecode.microbit.org/S66708-17604-37414-86430 ![pic_100](images/Case9/Case9_full_program.png)

## IoT (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. ![auto_fit](images/Case9/Case9_iot1.png)

Step 2

Make the programming part * On Blocks: * The WAN control command URL is: [http://control.smarthon.cc/publish?id=DeviceID&msg=ControlCommand](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”. ![auto_fit](images/Case9/Case9_iot2.png)

* When Button2 is clicked, it will direct to the URL with given device ID and command “closedoor”. ![auto_fit](images/Case9/Case9_iot3.png)

* Download the App in your phone to by .apk or scan QR code. ![auto_fit](images/Case9/Case9_iot4.png)

## 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”.

![auto_fit](images/Case9/Case9_result1.png)

![auto_fit](images/Case9/Case9_result3.png)

With app inventor and micro:bit, you can control the door open/close by mobile app!

![auto_fit](images/Case9/Case9_result4.gif)

## Think

Q1. How can we add password authentication to open the door?

Q2. We can install the servo to different position in the house (tips: modify the turning angle of the servo)