diff --git a/firmware/core/peripheral.cpp b/firmware/core/peripheral.cpp
index 12ac46b..5147d69 100644
--- a/firmware/core/peripheral.cpp
+++ b/firmware/core/peripheral.cpp
@@ -9,6 +9,7 @@
     digitalWrite(lockMagnetPin, HIGH);//lock door
     digitalWrite(lockDetectPin, HIGH);//enable pull-up
 
+    delay(400);
     lastDectVal = digitalRead(lockDetectPin);
     lastDectTime = millis();
 }
@@ -17,6 +18,7 @@
 {
     if (state == DoorLocked) {
         digitalWrite(lockMagnetPin, LOW);
+        preparedTimer = millis();
         state = DoorPreparedOpen;
         Serial.println("DoorPreparedOpen");
     }
@@ -46,7 +48,7 @@
         }
         break;
     case DoorPreparedOpen:
-        if (detect()) {
+        if (millis() - preparedTimer > DoorOpenTimeOut) {
             digitalWrite(lockMagnetPin, HIGH);
             state = DoorOpened;
             Serial.println("DoorOpened");
diff --git a/firmware/core/peripheral.h b/firmware/core/peripheral.h
index 30f6ad4..18d9500 100644
--- a/firmware/core/peripheral.h
+++ b/firmware/core/peripheral.h
@@ -9,6 +9,7 @@
 
 #define DetectorSwitchDelay 80
 #define LongPressThreshold 3000
+#define DoorOpenTimeOut  5000
 
 class Door
 {
@@ -17,6 +18,7 @@
         DoorLocked, DoorPreparedOpen, DoorOpened
     };
     DoorStateDef state;
+    unsigned long preparedTimer;
     unsigned long lastDectTime;
     unsigned char lastDectVal;
     bool detect(); //return true if lock detected door opened