docs : 초음파센서

Author: jeonghye-choi

부품&연결방법/초음파센서.md

@@ -2,20 +2,72 @@
 
 거리센서
 
+![image](https://user-images.githubusercontent.com/54584063/84301325-8e571980-ab8e-11ea-9d9d-9c5e5cd6b656.png)
+
+![image](https://user-images.githubusercontent.com/54584063/84301404-ad55ab80-ab8e-11ea-99df-2c44694576f6.png)
+
+- Vcc : 전압
+
+- Trigger : Input pin
+
+- Echo : Output pin
+
+- Grount
+
 ### ✔ 연결방법
 
+![image](https://user-images.githubusercontent.com/54584063/84300956-f5c09980-ab8d-11ea-8796-be2c8df96501.png)
+
 
 <br><br>
 
-### ✔ 
+### ✔ LAB
+
+- 초음파 센서 값 출력
+
+    ```js
+    int trigPin = 3;
+    int echoPin = 2;
 
+    void setup() {
+        Serial.begin(9600);
+        pinMode(trigPin, OUTPUT);
+        pinMode(echoPin, INPUT);
+    }
 
+    void loop() {
+        digitalWrite(trigPin, HIGH);
+        delay(10);
+        digitalWrite(trigPin, LOW);
+        
+        // Reads the echoPin, returns the sound wave travel time in microseconds 
+        float duration = pulseIn(echoPin, HIGH);
+
+        float distance = duration * 340 / 10000 / 2;
+        Serial.println(String("Distance(cm): ") + distance);
+        delay(500);
+    }
+
+    ```
 <br><br>
 
-### ✔ LAB
+### 🔎 pulseIn()
+
+pulseIn(pin, value)
+
+pulseIn(pin, value, timeout)
 
+value(LOW/HIGH) 로 있는 동안의 시간을 return 
+
+![image](https://user-images.githubusercontent.com/54584063/84301811-5dc3af80-ab8f-11ea-9e0c-c58ab6c83c95.png)
 
 
 <br><br>
 
-### 🔎 정리
+### 🔎 정리
+
+- Ultrasonic 초음파 센서
+
+    - 초음파 펄스를 출력, 수신
+
+    - 시간 측정 -> 거리 계산