diff --git a/ui/src/engine/diamond.rs b/ui/src/engine/diamond.rs
index d605dde..a6b4e39 100644
--- a/ui/src/engine/diamond.rs
+++ b/ui/src/engine/diamond.rs
@@ -345,10 +345,15 @@ impl EventHandler for Runner<DIAMOND_RING_LED_COUNT, DIAMOND_CENTER_LED_COUNT> {
                     }
                     QrScanSchema::Wifi => {
                         self.operator_idle.no_wlan();
+
+                        // temporarily increase the volume to ask wifi qr code
+                        let master_volume = self.sound.volume();
+                        self.sound.set_master_volume(40);
                         self.sound.queue(
                             sound::Type::Voice(sound::Voice::ShowWifiHotspotQrCode),
                             Duration::ZERO,
                         )?;
+                        self.sound.set_master_volume(master_volume);
                     }
                     QrScanSchema::User => {
                         self.operator_signup_phase.user_qr_code_ok();
diff --git a/ui/src/engine/pearl.rs b/ui/src/engine/pearl.rs
index afe4223..3d2de06 100644
--- a/ui/src/engine/pearl.rs
+++ b/ui/src/engine/pearl.rs
@@ -291,10 +291,15 @@ impl EventHandler for Runner<PEARL_RING_LED_COUNT, PEARL_CENTER_LED_COUNT> {
                     }
                     QrScanSchema::Wifi => {
                         self.operator_idle.no_wlan();
+
+                        // temporarily increase the volume to ask wifi qr code
+                        let master_volume = self.sound.volume();
+                        self.sound.set_master_volume(30);
                         self.sound.queue(
                             sound::Type::Voice(sound::Voice::ShowWifiHotspotQrCode),
                             Duration::ZERO,
                         )?;
+                        self.sound.set_master_volume(master_volume);
                     }
                     QrScanSchema::User => {
                         self.operator_signup_phase.user_qr_code_ok();
diff --git a/ui/src/sound/mod.rs b/ui/src/sound/mod.rs
index 764cf38..5ae4273 100644
--- a/ui/src/sound/mod.rs
+++ b/ui/src/sound/mod.rs
@@ -33,6 +33,9 @@ pub trait Player: fmt::Debug + Send {
     /// Returns a new handler to the shared queue.
     fn clone(&self) -> Box<dyn Player>;
 
+    /// Returns the master volume [0, 100].
+    fn volume(&self) -> u64;
+
     /// Sets the master volume.
     fn set_master_volume(&mut self, level: u64);
 
@@ -262,6 +265,10 @@ impl Player for Jetson {
         })
     }
 
+    fn volume(&self) -> u64 {
+        (self.volume * 100.0) as u64
+    }
+
     fn set_master_volume(&mut self, level: u64) {
         self.volume = level as f64 / 100.0;
     }