# Case 03: Automatic Gate ## Introduction A simple automatic sensor door. When the ultrasonic sensor detects that a person is approaching, the micro:bit controls the servo to automatically open the door. When no person is approaching, the micro:bit controls the servo to automatically close the door. ![](./images/case_03_01.png) ## Quick Start ### Materials Required Nezha expansion board × 1 micro:bit × 1 360° servo × 1 Sonar:bit × 1 RJ11 wire × 1 ***Tips: You may need to purchase [Nezha Inventor's Kit](https://shop.elecfreaks.com/products/elecfreaks-micro-bit-nezha-48-in-1-inventors-kit-without-micro-bit-board?_pos=2&_sid=ed1b6fbd2&_ss=r) if you want all the above compoents.*** ### Connection Diagram Connect the 360° servo to S1 and the ultrasonic sound sensor to J1 on the Nezha expansion board as the picture shows. ![](./images/case_03_03.png) ### Assembly Video Video reference: [https://youtu.be/nOh7YCmcotA](https://youtu.be/nOh7YCmcotA) ### Assembly Steps ![](./images/case_step_03_01.png) ![](./images/case_step_03_02.png) ![](./images/case_step_03_03.png) ![](./images/case_step_03_04.png) ![](./images/case_step_03_05.png) ![](./images/case_step_03_06.png) ![](./images/case_step_03_07.png) ![](./images/case_step_03_08.png) ![](./images/case_step_03_09.png) ![](./images/case_step_03_10.png) ![](./images/case_step_03_11.png) ## MakeCode Programming ### Step 1 Click "Advanced" in the MakeCode to see more choices. ![](./images/case_01_10.png) For programming, we need to add a package: click "Extensions" at the bottom of the MakeCode drawer and search with "PlanetX" in the dialogue box to download it. ![](./images/case_01_11.png) For programming, we need to add a package: click "Extensions" at the bottom of the MakeCode drawer and search with "nezha" in the dialogue box to download it. ![](./images/case_03_09.png) ***Notice:*** If you met a tip indicating that some codebases would be deleted due to incompatibility, you may continue as the tips say or create a new project in the menu. ### Step 2 ### Code as below: ![](./images/case_03_10.png) ### Reference Link:[https://makecode.microbit.org/_MssY8AXgCbkK](https://makecode.microbit.org/_MssY8AXgCbkK) You may also download it directly below:
### Result While the ultrasonic sound sensor detects any object, the gate opens automatically. ![](./images/case-gif-03.gif)