diff --git a/src/06-mini-project/daemon/gpio/button.c b/src/06-mini-project/daemon/gpio/button.c
index 87d329b..983c98a 100644
--- a/src/06-mini-project/daemon/gpio/button.c
+++ b/src/06-mini-project/daemon/gpio/button.c
@@ -1,16 +1,53 @@
 #include "button.h"
 
 #include <fcntl.h>
+#include <stdlib.h>
 #include <string.h>
 #include <sys/types.h>
 #include <unistd.h>
 #include <sys/epoll.h>
-
+#include <pthread.h>
+#include <stdio.h>
+#include <stdatomic.h>
+#include <stdbool.h>
 
 #define GPIO_EXPORT   "/sys/class/gpio/export"
 #define GPIO_UNEXPORT "/sys/class/gpio/unexport"
+#define GPIO_BTN_BASE "/sys/class/gpio/gpio"
+
+#define MAX_EVENTS 10
+atomic_int ev_tail = 0;
+
+int epoll_fd;
+struct epoll_event ev[MAX_EVENTS];
+pthread_t epoll_thread_id;
+
+int btn_add_epoll_event(btn_t* btn);
+void epoll_init();
+static void* epoll_thread(void* arg);
+
+btn_t* btn_init(btn_type_t type) {
+    btn_t* btn = malloc(sizeof(btn_t));
+    if (btn == NULL) return NULL;
+
+    char gpio_path[32] = GPIO_BTN_BASE;
+    char pin[32];
+    switch (type) {
+        case BTN_INCREASE:
+            strcpy(pin, GPIO_BTN_INCREASE);
+            break;
+        case BTN_DECREASE:
+            strcpy(pin, GPIO_BTN_DECREASE);
+            break;
+        case BTN_MODE:
+            strcpy(pin, GPIO_BTN_MODE);
+            break;
+        default:
+            printf("Invalid button type\n");
+            return NULL;
+    }
+    strcat(gpio_path, pin);
 
-int btn_open(const char* gpio_path, const char* pin) {
     int f = open(GPIO_UNEXPORT, O_WRONLY);
     write(f, pin, strlen(pin));
     close(f);
@@ -40,5 +77,74 @@ int btn_open(const char* gpio_path, const char* pin) {
     strcat(value_path, "/value");
 
     f = open(value_path, O_RDONLY);
-    return f;
+    if (f == -1) {
+        printf("Failed to setup button on pin %s\n", pin);
+        return NULL;
+    }
+    btn->gpio = f;
+
+    // Dummy read to clear initial state before waiting
+    char buf[2];
+    pread(btn->gpio, buf, sizeof(buf), 0);
+
+    btn_add_epoll_event(btn);
+
+    return btn;
+}
+
+void btn_set_callback(btn_t* btn, btn_callback_t callback) {
+    btn->callback = callback;
+}
+
+// TODO add mutex to protect this function
+int btn_add_epoll_event(btn_t* btn) {
+    int tail = atomic_fetch_add(&ev_tail, 1);
+    if (tail >= MAX_EVENTS-1) {
+        perror("Failed to add epoll event");
+        return -1;
+    }
+
+    if (tail == 0) {
+        epoll_init();
+    }
+
+    // EPOLLIN is working well as EPOLLPRI (which is more used for priority data)
+    // EPOLLERR is used to detect if there is an error
+    // EPOLLET is for edge triggered mode (non-blocking)
+    ev[tail].events = EPOLLIN | EPOLLERR | EPOLLET;
+    ev[tail].data.fd = btn->gpio;
+    int ret = epoll_ctl(epoll_fd, EPOLL_CTL_ADD, btn->gpio, &ev[tail]);
+    if (ret < 0) {
+        perror("Failed to add epoll event");
+        return -1;
+    }
+    return tail;
+}
+
+void epoll_init(){
+    if (pthread_create(&epoll_thread_id, NULL, epoll_thread, NULL) != 0) {
+        perror("Failed to create timer thread");
+        exit(30);
+    }
+}
+
+static void* epoll_thread(void* arg) {
+    int epfd = epoll_create1(0);
+    if (epfd < 0) {
+        perror("Failed to create epoll instance");
+        exit(EXIT_FAILURE);
+    }
+    epoll_fd = epfd;
+
+    while (1) {
+        struct epoll_event events[MAX_EVENTS];
+        int n = epoll_wait(epoll_fd, events, MAX_EVENTS, -1);
+        if (n < 0) {
+            perror("epoll_wait");
+            continue;
+        }
+        for (int i = 0; i < n; i++) {
+
+        }
+    }
 }
diff --git a/src/06-mini-project/daemon/gpio/led.c b/src/06-mini-project/daemon/gpio/led.c
index 701ee0b..dcee127 100644
--- a/src/06-mini-project/daemon/gpio/led.c
+++ b/src/06-mini-project/daemon/gpio/led.c
@@ -8,8 +8,33 @@
 #include <sys/epoll.h>
 #include <sys/inotify.h>
 #include <pthread.h>
+#include <stdio.h>
 
-int led_open(const char* gpio_path, const char* pin) {
+#define GPIO_EXPORT     "/sys/class/gpio/export"
+#define GPIO_UNEXPORT   "/sys/class/gpio/unexport"
+#define GPIO_LED_BASE   "/sys/class/gpio/gpio"
+
+#include <stdlib.h>
+
+led_t* led_init(led_type_t type) {
+    led_t* led = malloc(sizeof(led_t));
+    if (led == NULL) return NULL;
+
+    // Concatenate GPIO LED path based on type
+    char gpio_path[32] = GPIO_LED_BASE;
+    char pin[32];
+    switch (type) {
+        case LED_STATUS:
+            strcpy(pin, GPIO_LED_STATUS);
+            break;
+        case LED_POWER:
+            strcpy(pin, GPIO_LED_POWER);
+            break;
+        default:
+            printf("Invalid LED type\n");
+            return NULL;
+    }
+    strcat(gpio_path, pin);
 
     // unexport pin out of sysfs (reinitialization)
     int f = open(GPIO_UNEXPORT, O_WRONLY);
@@ -36,13 +61,38 @@ int led_open(const char* gpio_path, const char* pin) {
     strcat(value_path, "/value");
 
     f = open(value_path, O_RDWR);
-    return f;
+    if (f == -1) {
+        printf("Failed to setup led on pin %s\n", pin);
+        return NULL;
+    }
+
+    led->gpio = f;
+    return led;
 }
 
-void led_on(int led) {
-    pwrite(led, "1", sizeof("1"), 0);
+void led_on(led_t* led) {
+    if (led == NULL) {
+        return;
+    }
+    pwrite(led->gpio, "1", sizeof("1"), 0);
 }
 
-void led_off(int led) {
-    pwrite(led, "0", sizeof("0"), 0);
+void led_off(led_t* led) {
+    if (led == NULL) {
+        return;
+    }
+    pwrite(led->gpio, "0", sizeof("0"), 0);
+}
+
+void led_toggle(led_t* led) {
+    if (led == NULL) {
+        return;
+    }
+    char value[2];
+    pread(led->gpio, value, sizeof(value), 0);
+    if (value[0] == '0') {
+        led_on(led);
+    } else {
+        led_off(led);
+    }
 }
diff --git a/src/06-mini-project/daemon/main.c b/src/06-mini-project/daemon/main.c
index 3c2acc9..5b299c3 100644
--- a/src/06-mini-project/daemon/main.c
+++ b/src/06-mini-project/daemon/main.c
@@ -14,13 +14,7 @@
 #include "gpio/led.h"
 #include "gpio/button.h"
 
-/*
- * status led - gpioa.10 --> gpio10
- * power led  - gpiol.10 --> gpio362
- */
 
-#define GPIO_LED       "/sys/class/gpio/gpio10"
-#define LED            "10"
 
 #define GPIO_BTN1      "/sys/class/gpio/gpio0"
 #define BTN1           "0"
@@ -49,33 +43,10 @@ const char* BTN[NBR_BTN] =  {BTN1, BTN2, BTN3};
 void* btn_thread(void* arg) {
     ThreadData* data = (ThreadData*)arg;
 
-    // Open all button with the right flags
-    int btn[NBR_BTN] = {0};
-    for(int i=0; i<NBR_BTN; i++) {
-        btn[i] = btn_open(GPIO_BTN[i], BTN[i]);
-        if (btn[i] < 0) {
-            perror("Failed to open button");
-        }
-    }
+    btn_init(BTN_INCREASE);
+    btn_init(BTN_DECREASE);
+    btn_init(BTN_MODE);
 
-    // Create epoll instance to control all button files
-    int epfd = epoll_create1(0);
-    if (epfd < 0) {
-        perror("Failed to create epoll");
-    }
-
-    // Add buttons to epoll
-    struct epoll_event ev[NBR_BTN];
-    // EPOLLIN is working well as EPOLLPRI (which is more used for priority data)
-    // EPOLLERR is used to detect if there is an error
-    // EPOLLET is for edge triggered mode (non-blocking)
-    for(int i=0; i<NBR_BTN; i++) {
-        ev[i].events = EPOLLIN | EPOLLERR | EPOLLET;
-        ev[i].data.fd = btn[i];
-        if (epoll_ctl(epfd, EPOLL_CTL_ADD, btn[i], &ev[i]) < 0) {
-            perror("Failed to add button to epoll");
-        }
-    }
 
     // Dummy read to clear initial state before waiting
     char buf[2];
@@ -141,13 +112,12 @@ void* btn_thread(void* arg) {
         close(btn[i]);
     }
     close(epfd);
-    return NULL;
 }
 
 static void* timer_thread(void* arg) {
     ThreadData* data = (ThreadData*)arg;
 
-    int led = led_open(GPIO_LED, LED);
+    led_t* led = led_init(LED_POWER);
     led_off(led);
 
 
@@ -175,11 +145,13 @@ static void* timer_thread(void* arg) {
         int delay = 0;
         if (isLedOn == 0) {
             delay = time_on_ms; // 2% duty
-            led_on(led);
+            // led_on(led);
+            led_toggle(led);
             isLedOn = 1;
         } else {
             delay = time_off_ms; // rest of the period
-            led_off(led);
+            // led_off(led);
+            led_toggle(led);
             isLedOn = 0;
         }
 
@@ -190,8 +162,6 @@ static void* timer_thread(void* arg) {
 }
 
 int main(int argc, char* argv[]) {
-    (void)argc;
-    (void)argv;
     ThreadData data;
     pthread_t thread;
     openlog("CSEL Logs", LOG_PID, LOG_USER);