diff --git a/blitzercontroller/src/main.cpp b/blitzercontroller/src/main.cpp
index 3b179ed..ce409ce 100644
--- a/blitzercontroller/src/main.cpp
+++ b/blitzercontroller/src/main.cpp
@@ -1,28 +1,35 @@
 #include <Arduino.h>
 
-
+float flashspeed=20; //in kmh
+unsigned long flashdeadtime=1000; //in ms
 
 #define PIN_SW1 D6
-#define PIN_SW2 D7
+#define PIN_SW2 D5
+#define PIN_TRIGGER D7
 volatile boolean sw1_flag = false;
 volatile boolean sw2_flag = false;
 
 unsigned long sw1_lastTime=0;
 unsigned long sw2_lastTime=0;
 
-float calib_distance=0.2; //distance of sensors in meters
+float calib_distance=0.062; //distance of sensors in meters
 
-#define SWDEBOUNCE 100
+#define SWDEBOUNCE 100000
 
-void interrupt_sw1();
-void interrupt_sw2();
-float getLastSpeed();
+ICACHE_RAM_ATTR void interrupt_sw1();
+ICACHE_RAM_ATTR void interrupt_sw2();
+float getLastSpeed1();
+float getLastSpeed2();
+void doTrigger1();
+void doTrigger2();
 
 void setup() {
   pinMode(PIN_SW1, INPUT_PULLUP);
   pinMode(PIN_SW2, INPUT_PULLUP);
+  pinMode(PIN_TRIGGER, OUTPUT);
   attachInterrupt(digitalPinToInterrupt(PIN_SW1), interrupt_sw1, FALLING);
   attachInterrupt(digitalPinToInterrupt(PIN_SW2), interrupt_sw2, FALLING);
+  digitalWrite(PIN_TRIGGER, HIGH); //active low
 
   Serial.begin(115200);
 }
@@ -31,33 +38,84 @@ void loop() {
 
   if (sw1_flag){
     sw1_flag=false;
-    sw1_lastTime=millis();
+    sw1_lastTime=micros();
     Serial.println("SW1");
+    doTrigger1();
   }
   if (sw2_flag){
     sw2_flag=false;
-    sw2_lastTime=millis();
+    sw2_lastTime=micros();
     Serial.println("SW2");
-
-    float speed=getLastSpeed();
-    Serial.print("Speed="); Serial.print(speed); Serial.println(" m/s");
-    Serial.print("     "); Serial.print(speed*3.6); Serial.println(" km/h");
+    doTrigger2();    
   }
   
 }
 
-void interrupt_sw1() {
-  if (sw1_lastTime+SWDEBOUNCE<millis()){
+
+void doTrigger1() {
+  static unsigned long last_flash=0;
+
+  
+  float speed=getLastSpeed1();
+  
+  if (speed*3.6<0.1) {
+    return;
+  }
+
+  if (millis()-last_flash>flashdeadtime) { //deadtime
+    last_flash=millis();
+
+    if (speed*3.6 >= flashspeed) {
+      Serial.print("> Speed="); Serial.print(speed*3.6); Serial.println(" km/h");
+      Serial.println("Flash");
+      pinMode(PIN_TRIGGER, INPUT); //high impedance
+      delay(100);      
+      pinMode(PIN_TRIGGER, OUTPUT); digitalWrite(PIN_TRIGGER, LOW);
+    }
+  }
+}
+
+
+void doTrigger2() {
+  static unsigned long last_flash=0;
+  
+  float speed=getLastSpeed2();
+  
+
+  if (speed*3.6<0.1) {
+    return;
+  }
+
+  if (millis()-last_flash>flashdeadtime) { //deadtime
+    last_flash=millis();
+
+    if (speed*3.6 >= flashspeed) {
+      Serial.print("> Speed="); Serial.print(speed*3.6); Serial.println(" km/h");
+      Serial.println("Flash");
+      pinMode(PIN_TRIGGER, INPUT); //high impedance
+      delay(100);      
+      pinMode(PIN_TRIGGER, OUTPUT); digitalWrite(PIN_TRIGGER, LOW);
+    }
+  }
+}
+
+
+
+ICACHE_RAM_ATTR void interrupt_sw1() {
+  if (sw1_lastTime+SWDEBOUNCE<micros()){
     sw1_flag=true;
   }
 }
 
-void interrupt_sw2() {
-  if (sw2_lastTime+SWDEBOUNCE<millis()){
+ICACHE_RAM_ATTR void interrupt_sw2() {
+  if (sw2_lastTime+SWDEBOUNCE<micros()){
     sw2_flag=true;
   }
 }
 
-float getLastSpeed() {
-  return calib_distance/((sw2_lastTime-sw1_lastTime)/1000.0);
-}
\ No newline at end of file
+float getLastSpeed1() {
+  return calib_distance/((sw1_lastTime-sw2_lastTime)/1000000.0);
+}
+float getLastSpeed2() {
+  return calib_distance/((sw2_lastTime-sw1_lastTime)/1000000.0);
+}