diff --git a/src/controller.py b/src/controller.py
index d281e6e..10e2355 100644
--- a/src/controller.py
+++ b/src/controller.py
@@ -1,15 +1,29 @@
 import serial
+import time
 
+# Open a serial port
 ser = serial.Serial('/dev/ttyACM0', 9600, timeout=1)
-ser.readline()
-
-up = True
-while True:
-    data = ser.readline()
-    if up:
-        command = 'a'
-    else:
-        command = '0'
-    ser.write(bytes(command, 'utf-8'))
-    up = not up
+time.sleep(1)
+print(ser.readline())
+
+# Length that corresponds each volume
+len_0mL = '1820'
+len_1mL = '1755'
+len_5mL = '1528'
+len_10mL = '1286'
+
+# Initialize
+ser.write(bytes(len_0mL, 'ascii'))
+time.sleep(5)
+print(ser.readline())
+
+for _ in range(5):
+    # Aspirate 5 mL
+    ser.write(bytes(len_5mL, 'ascii'))
+    time.sleep(5)
+    print(ser.readline())
+    # Dispense liquid
+    ser.write(bytes(len_0mL, 'ascii'))
+    time.sleep(5)
+    print(ser.readline())
 ser.close()
diff --git a/src/pipette.ino b/src/pipette.ino
index 88d40e8..2dd627b 100644
--- a/src/pipette.ino
+++ b/src/pipette.ino
@@ -1,14 +1,11 @@
 #include <Servo.h>
-
 Servo myServo;
 
-int len0 = 1820;
-int len5 = 1522;
-int len10 = 1286;
-
+#define len0 (1820)
 #define PIN_SERVO (8)
 
-void setup() {
+void setup()
+{
   Serial.begin(9600);
   Serial.println("Start!");
   myServo.attach(PIN_SERVO);
@@ -16,22 +13,20 @@ void setup() {
   delay(5000);
 }
 
-void loop() {
-  char key;
-   if (Serial.available()) {
-     key = Serial.read();
-     Serial.println(key);
-     switch (key) {
-      case 'a':
-        myServo.writeMicroseconds(len10);
-        break;
-      case '5':
-        myServo.writeMicroseconds(len5);
-        break;
-      case '0':
-        myServo.writeMicroseconds(len0);
-        break;
+
+void loop()
+{
+   if ( Serial.available() ) {
+     String len_str = Serial.readString();
+     Serial.print("Received Value: ");
+     Serial.println(len_str);
+     int len = len_str.toInt();
+     if (len >= 1000 && len <= 2000)
+     {
+        Serial.println("Valid value");
+        myServo.writeMicroseconds(len);
+     } else {
+        Serial.println("Invalid value");
      }
-     delay(1000);
    }
 }