diff --git a/ch32v-insert-coin/src/app.rs b/ch32v-insert-coin/src/app.rs
index 54a2768..91f5b0c 100644
--- a/ch32v-insert-coin/src/app.rs
+++ b/ch32v-insert-coin/src/app.rs
@@ -44,6 +44,16 @@ mod settings {
                 Self::Maximum => 1,
             }
         }
+
+        pub fn as_brightness_divisor(&self) -> u8 {
+            match self {
+                Self::Off => u8::MAX,
+                Self::Low => 4,
+                Self::Medium => 3,
+                Self::High => 2,
+                Self::Maximum => 1,
+            }
+        }
     }
 
     #[derive(Clone, Copy)]
@@ -295,27 +305,27 @@ impl App {
         if self.timers.led0_timer.need_service() {
             self.timers.led0_timer.service();
             self.sequences.led0.next();
-            self.services
-                .led0
-                .set_amplitude(self.sequences.led0.get_value());
+            self.services.led0.set_amplitude(
+                self.sequences.led0.get_value() / self.settings.brightness.as_brightness_divisor(),
+            );
             // #[cfg(feature = "enable_print")]
             // println!("led0 sevice {}", self.sequences.led0.get_value());
         }
         if self.timers.led1_timer.need_service() {
             self.timers.led1_timer.service();
             self.sequences.led1.next();
-            self.services
-                .led1
-                .set_amplitude(self.sequences.led1.get_value());
+            self.services.led1.set_amplitude(
+                self.sequences.led1.get_value() / self.settings.brightness.as_brightness_divisor(),
+            );
             // #[cfg(feature = "enable_print")]
             // println!("led1 service");
         }
         if self.timers.led2_timer.need_service() {
             self.timers.led2_timer.service();
             self.sequences.led2.next();
-            self.services
-                .led2
-                .set_amplitude(self.sequences.led2.get_value());
+            self.services.led2.set_amplitude(
+                self.sequences.led2.get_value() / self.settings.brightness.as_brightness_divisor(),
+            );
             // #[cfg(feature = "enable_print")]
             // println!("led2 service");
         }
@@ -357,9 +367,9 @@ impl App {
         println!("new volume: {:?}", self.settings.volume);
     }
     pub fn brightness_button(&mut self) {
+        self.settings.brightness.next();
         #[cfg(feature = "enable_print")]
-        println!("brightness button app handler");
-        // TODO
+        println!("new brightness: {:?}", self.settings.brightness);
     }
     pub fn main_button(&mut self) {
         // TODO
@@ -376,7 +386,6 @@ impl App {
 // 3. amp_en control
 //
 // LED:
-// 1. brightness control
 //
 // INTERFACE:
 // 1. short press handling
@@ -391,3 +400,4 @@ impl App {
 //
 // STRETCH TODO LIST
 // 1. clean up edge detector
+// 2. better handling for pwm scaling (brightness / volume)
diff --git a/ch32v-insert-coin/src/main.rs b/ch32v-insert-coin/src/main.rs
index 9990634..288203b 100644
--- a/ch32v-insert-coin/src/main.rs
+++ b/ch32v-insert-coin/src/main.rs
@@ -329,8 +329,8 @@ fn app_main(mut p: hal::Peripherals) -> ! {
     app.init();
     loop {
         // system servicing
-        //
-        // edge detector
+
+        // volume edge detector
         if !volume_btn_input.active() {
             let volume_btn_curr = volume_btn_input.is_high_immediate();
             if volume_btn_prev != volume_btn_curr {
@@ -349,6 +349,25 @@ fn app_main(mut p: hal::Peripherals) -> ! {
             volume_btn_input.reset();
         }
 
+        // brightness edge detector
+        if !light_ctrl_btn_input.active() {
+            let light_ctrl_btn_curr = light_ctrl_btn_input.is_high_immediate();
+            if light_ctrl_btn_prev != light_ctrl_btn_curr {
+                light_ctrl_btn_input.begin();
+                light_ctrl_btn_prev = light_ctrl_btn_curr;
+            }
+        }
+
+        light_ctrl_btn_input.service();
+        if light_ctrl_btn_input.ready() {
+            #[cfg(feature = "enable_print")]
+            println!("brightness btn value: {}", light_ctrl_btn_input.value());
+            if !light_ctrl_btn_input.value() {
+                app.brightness_button();
+            }
+            light_ctrl_btn_input.reset();
+        }
+
         // systick tick
         if unsafe {
             #[allow(static_mut_refs)]