diff --git a/src/handler/matrix.py b/src/handler/matrix.py
index 9d3de50..929111e 100644
--- a/src/handler/matrix.py
+++ b/src/handler/matrix.py
@@ -20,6 +20,11 @@ class MatrixDisplay:
         self.device.contrast(self.contrast)
 
     def set_contrast(self, contrast: int):
+        """Set contrast for all actions.
+
+        Args:
+            contrast (int): [0, 255]
+        """
         self.contrast = contrast
         self.device.contrast(self.contrast)
 
@@ -36,8 +41,12 @@ class MatrixDisplay:
             virtual.set_position((offset, 0))
             time.sleep(self.text_speed)
 
-    def flash(self, count=1):
-        self.device.contrast(self.contrast)
+    def flash(self, count=1, contrast=None):
+        if contrast:
+            self.device.contrast(contrast)
+        else:
+            self.device.contrast(self.contrast)
+
         while count > 0:
             with canvas(self.device) as draw:
                 draw.rectangle((0, 0, 31, 7), outline="white", fill="white")
diff --git a/src/main.py b/src/main.py
index 4b77ed6..9e4437e 100644
--- a/src/main.py
+++ b/src/main.py
@@ -1,8 +1,7 @@
 import asyncio
 from typing import Optional
 
-import requests
-from fastapi import FastAPI, HTTPException
+from fastapi import FastAPI
 from fastapi.middleware.cors import CORSMiddleware
 
 from actions import dht22_sensor, display_time, log_temperature, matrix_display
@@ -85,9 +84,10 @@ async def history():
 
 
 @app.post("/flash")
-async def flash(count: int = 1):
-    await queue.add_action_to_queue(matrix_display.flash, count)
-
+async def flash(count: int = 1, contrast: Optional[int] = None):
+    await queue.add_action_to_queue(
+        matrix_display.flash, count=count, contrast=contrast
+    )
     return {"message": "Display flashed"}