diff --git a/week4-4/week4-4.ino b/week4-4/week4-4.ino
index 9836f6a..0e9a934 100644
--- a/week4-4/week4-4.ino
+++ b/week4-4/week4-4.ino
@@ -3,7 +3,7 @@
 const int LED[] = {11, 10, 9, 8, 7, 6, 5, 4};
 const int BUTTON[] = {A0, A1, A2, A3};
 
-int clk = 0;  // 定義每個模式中的計數器
+unsigned int clk = 0;  // the counter in every mode
 
 void setup() {
   for (int i = 0; i < 8; i++) {
@@ -15,23 +15,29 @@ void setup() {
   }
 }
 
+/*
+ * Function: call_interval
+ * Call a function per DELAY
+ * 
+ * f: the function being called
+ * 
+ * Side effect: increase clk per DELAY
+ */
 void call_interval( void (*f)(unsigned int) ) {
   static unsigned long checkpoint = 0;
   if (millis() - checkpoint > DELAY) {
-    for (int i = 0; i < 8; i++) {
-      digitalWrite(LED[7 - i], !((value >> i) % 2));
-    }
+    (*f)(clk);
     clk += 1;
     checkpoint = millis();
   }
 }
 
 /*
- * Function: get_mode
- * Return the current mode from buttons input
- * 
- * Side effects: reset the clk on button pressed
- */
+   Function: get_mode
+   Return the current mode from buttons input
+
+   Side effects: reset the clk on button pressed
+*/
 unsigned int get_mode() {
   static int last = 0;
   for (int i = 0; i < 4; i++) {
@@ -45,20 +51,12 @@ unsigned int get_mode() {
 }
 
 /*
- * Function: binary
- * Display the LED as binary of clk
- * 
- * increase clk per DELAY
- * Side effect: increase clk per DELAY
- */
+   Function: binary
+   Display the LED as binary of clk
+*/
 void binary(unsigned int value) {
-  static unsigned long checkpoint = 0;
-  if (millis() - checkpoint > DELAY) {
-    for (int i = 0; i < 8; i++) {
-      digitalWrite(LED[7 - i], !((value >> i) % 2));
-    }
-    clk += 1;
-    checkpoint = millis();
+  for (int i = 0; i < 8; i++) {
+    digitalWrite(LED[7 - i], !((value >> i) % 2));
   }
 }
 
@@ -67,16 +65,12 @@ void gray_code(unsigned int value) {
 }
 
 /*
- * Function: random_popup
- * Randomly blink LED
- * 
- * Randomly select LED. Each LED will turn on for 3 clk
- * Side effect: increase clk per DELAY
- */
-void random_popup() {
-  static unsigned long checkpoint = 0;
-  static int hp[] = {0, 0, 0, 0, 0, 0, 0, 0};
-  
+   Function: random_popup
+   Randomly select LED. Each LED will be turned on for 3 clk
+*/
+void random_popup(unsigned int clk) {
+  static int hp[8];
+
   // Reset hp on mode changing
   if (clk == 0) {
     for (int i = 0; i < 8; i++) {
@@ -84,26 +78,20 @@ void random_popup() {
     }
   }
 
-  if (millis() - checkpoint > DELAY) {
-    for (int i = 0; i < 8; i++) {
-
-      // Decrease hp
-      if (hp[i] > 0) {
-        hp[i] -= 1;
-      }
-      digitalWrite(LED[i], !(hp[i]));
+  for (int i = 0; i < 8; i++) {
+    // Decrease hp
+    if (hp[i] > 0) {
+      hp[i] -= 1;
     }
-
-    // randomly select LED which is not turned on
-    int choice;
-    do {
-      choice = random(8);
-    } while (hp[choice] > 0);
-    hp[choice] = 4;
-    
-    checkpoint = millis();
-    clk++;
+    digitalWrite(LED[i], !(hp[i]));
   }
+
+  // randomly select LED which is not turned on
+  int choice;
+  do {
+    choice = random(8);
+  } while (hp[choice] > 0);
+  hp[choice] = 4;
 }
 
 void clear_all() {
@@ -115,13 +103,13 @@ void clear_all() {
 void loop() {
   const int mode = get_mode();
   if (mode == 1) {
-    binary(clk);
+    call_interval(binary);
   }
   if (mode == 2) {
-    gray_code(clk);
+    call_interval(gray_code);
   }
   if (mode == 3) {
-    random_popup();
+    call_interval(random_popup);
   }
   if (mode == 4) {
     clear_all();
diff --git a/week5-1/week5-1.ino b/week5-1/week5-1.ino
new file mode 100644
index 0000000..b24d973
--- /dev/null
+++ b/week5-1/week5-1.ino
@@ -0,0 +1,45 @@
+const unsigned int scan[] = {5, 6, 7, 8};
+#define DATA 10
+#define LATCH 11
+#define CLK 12
+
+byte numbers[] = {
+  0xC0, 0xF9, 0xA4, 0xB0, 0x99, 
+  0x92, 0x82, 0xF8, 0x80, 0x90
+};
+
+void setup() {
+  for (int i = 0; i < 4; i++) {
+    pinMode(scan[i], OUTPUT);
+    digitalWrite(scan[i], HIGH);
+  }
+  pinMode(DATA, OUTPUT);
+  pinMode(LATCH, OUTPUT);
+  pinMode(CLK, OUTPUT);
+}
+
+void setDigits(int number, int digits[4]) {
+  for (int i = 0; i < 4; i++) {
+    digits[i] = number % 10;
+    number /= 10;
+  }
+}
+
+void loop() {
+  static int number = 0;
+  static unsigned long checkpoint = 0;
+  static int digits[4];
+  for (int i = 0; i < 4; i++) {
+    digitalWrite(LATCH, LOW);
+    shiftOut(DATA, CLK, MSBFIRST, numbers[digits[i]]);
+    digitalWrite(LATCH, HIGH);
+    digitalWrite(scan[i], LOW);
+    delay(1);
+    digitalWrite(scan[i], HIGH);
+  }
+  if (millis() - checkpoint > 200) {
+    number++;
+    setDigits(number, digits);
+    checkpoint = millis();
+  }
+}
diff --git a/week5-3/week5-3.ino b/week5-3/week5-3.ino
new file mode 100644
index 0000000..5f64d40
--- /dev/null
+++ b/week5-3/week5-3.ino
@@ -0,0 +1,50 @@
+const unsigned int scan[] = {5, 6, 7, 8};
+#define DATA 10
+#define LATCH 11
+#define CLK 12
+const int date[] = {2022, 323};
+
+byte numbers[] = {
+  0xC0, 0xF9, 0xA4, 0xB0, 0x99,
+  0x92, 0x82, 0xF8, 0x80, 0x90
+};
+
+void setup() {
+  for (int i = 0; i < 4; i++) {
+    pinMode(scan[i], OUTPUT);
+    digitalWrite(scan[i], HIGH);
+  }
+  pinMode(DATA, OUTPUT);
+  pinMode(LATCH, OUTPUT);
+  pinMode(CLK, OUTPUT);
+}
+
+void setDigits(int number, int digits[4]) {
+  for (int i = 0; i < 4; i++) {
+    digits[i] = number % 10;
+    number /= 10;
+  }
+}
+
+void show(int digits[4]) {
+  for (int i = 0; i < 4; i++) {
+    digitalWrite(LATCH, LOW);
+    shiftOut(DATA, CLK, MSBFIRST, numbers[digits[i]]);
+    digitalWrite(LATCH, HIGH);
+    digitalWrite(scan[i], LOW);
+    delay(1);
+    digitalWrite(scan[i], HIGH);
+  }
+}
+
+void loop() {
+  static unsigned long checkpoint = 0;
+  static int digits[4];
+  static bool mode = false;
+  show(digits);
+  if (millis() - checkpoint > 500) {
+    mode = !mode;
+    setDigits(date[mode], digits);
+    checkpoint = millis();
+  }
+}
diff --git a/week5-4/week5-4.ino b/week5-4/week5-4.ino
new file mode 100644
index 0000000..327f3d3
--- /dev/null
+++ b/week5-4/week5-4.ino
@@ -0,0 +1,42 @@
+const unsigned int scan[] = {5, 6, 7, 8};
+#define DATA 10
+#define LATCH 11
+#define CLK 12
+
+byte numbers[] = {
+  0xC0, 0xF9, 0xA4, 0xB0, 0x99,
+  0x92, 0x82, 0xF8, 0x80, 0x90
+};
+
+void setup() {
+  for (int i = 0; i < 4; i++) {
+    pinMode(scan[i], OUTPUT);
+    digitalWrite(scan[i], HIGH);
+  }
+  pinMode(DATA, OUTPUT);
+  pinMode(LATCH, OUTPUT);
+  pinMode(CLK, OUTPUT);
+}
+
+void show(int digits[10], int shift) {
+  for (int i = 0; i < 4; i++) {
+    digitalWrite(LATCH, LOW);
+    shiftOut(DATA, CLK, MSBFIRST, numbers[digits[(shift + i) % 10]]);
+    digitalWrite(LATCH, HIGH);
+    digitalWrite(scan[3-i], LOW);
+    delay(1);
+    digitalWrite(scan[3-i], HIGH);
+  }
+}
+
+void loop() {
+  static unsigned long checkpoint = 0;
+  static int digits[10] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
+  static int count = 0;
+  show(digits, count);
+  if (millis() - checkpoint > 500) {
+    count--;
+    if (count < 0) count = 9;
+    checkpoint = millis();
+  }
+}
diff --git a/week5-5/week5-5.ino b/week5-5/week5-5.ino
new file mode 100644
index 0000000..b2e95b0
--- /dev/null
+++ b/week5-5/week5-5.ino
@@ -0,0 +1,90 @@
+const unsigned int scan[] = {5, 6, 7, 8};
+const unsigned int LED[] = {9, 13, 2, 3};
+const unsigned int BUTTON[] = {A0, A1};
+#define DATA 10
+#define LATCH 11
+#define CLK 12
+
+void setup() {
+  for (int i = 0; i < 4; i++) {
+    pinMode(scan[i], OUTPUT);
+    digitalWrite(scan[i], HIGH);
+  }
+  for (int i = 0; i < 4; i++) {
+    pinMode(LED[i], OUTPUT);
+    digitalWrite(LED[i], HIGH);
+  }
+  for (int i = 0; i < 2; i++) {
+    pinMode(BUTTON[i], INPUT);
+  }
+  pinMode(DATA, OUTPUT);
+  pinMode(LATCH, OUTPUT);
+  pinMode(CLK, OUTPUT);
+}
+
+int get_mode() {
+  static int last = 0;
+  for (int i = 0; i < 2; i++) {
+    if (!digitalRead(BUTTON[i])) {
+      last = i+1;
+      return last;
+    }
+  }
+  return last;
+}
+
+void show(byte digits[4]) {
+  for (int i = 0; i < 4; i++) {
+    digitalWrite(LATCH, LOW);
+    shiftOut(DATA, CLK, MSBFIRST, ~digits[i]);
+    digitalWrite(LATCH, HIGH);
+    digitalWrite(scan[3 - i], LOW);
+    delay(1);
+    digitalWrite(scan[3 - i], HIGH);
+  }
+}
+
+void mode_display() {
+  static byte digits[4];
+  static byte p = 0;
+  static unsigned long checkpoint = 0;
+  show(digits);
+  if (millis() - checkpoint > 200) {
+    if (p == 4) {
+      // all the numbers are turned on, reset
+      p = 0;
+      for (int i = 0; i < 4; i++) digits[i] = 0;
+    }
+    digits[p] <<= 1;
+    digits[p] += 1;
+    if (digits[p] == 0xFF) {
+      // if current digit is full, change to the next one
+      p++;
+    }
+    checkpoint = millis();
+  }
+}
+
+void mode_led() {
+  static unsigned long checkpoint;
+  static int c = 0;
+  if (millis() - checkpoint > 200) {
+    for (int i = 0; i < 4; i++) {
+      digitalWrite(LED[i], i != c%4);
+    }
+    c++;
+    checkpoint = millis();
+  }
+}
+
+void loop() {
+  switch (get_mode()) {
+    case 1:
+      mode_display();
+      break;
+      
+    case 2:
+      mode_led();
+      break;
+  }
+}