diff --git a/Software/Sender/Sender.ino b/Software/Sender/Sender.ino
index 1c01f47..8130a80 100644
--- a/Software/Sender/Sender.ino
+++ b/Software/Sender/Sender.ino
@@ -9,7 +9,7 @@
 // include the library code:
 #include <SoftRS485.h>
 
-#define PROGRAM "RS485-Nano 2.1 / Sender 1.1"
+#define PROGRAM "RS485-Nano 2.1 / Sender 1.2"
 
 #define BTN_INT 3 // button interrupt pin
 #define Max485_RO 2 // read-output of Max485
@@ -17,7 +17,7 @@
 #define Max485_DE 8 // data enable of Max485
 #define Max485_DI 9 // data input of Max485
 
-#define TRESHOLD 200000 // 200ms
+#define TRESHOLD 1024
 #define ID 0
 // 0=Test
 // 1=Arbeitszimmer
@@ -27,12 +27,19 @@
 //#define LOG_TO_SERIAL
 #define SEND_485
 
+boolean raw_states[8];
 boolean states[8];
+unsigned long capacitor[8];
 unsigned long times[8];
 
 
 
 void setup(){
+  for (int i=0; i<8;i++) {
+    capacitor[i] = 0;
+    raw_states[i] = LOW;
+    states[i] = LOW;
+  }
   Serial.begin(115200);
   init485(Max485_RO,Max485_RE,Max485_DE,Max485_DI); // library initialization:
   pinMode(BTN_INT,INPUT_PULLUP);
@@ -45,7 +52,7 @@ void setup(){
   pinMode(20,INPUT_PULLUP);
   pinMode(21,INPUT_PULLUP);
 
-  attachInterrupt(digitalPinToInterrupt(2),isr,CHANGE);
+  attachInterrupt(digitalPinToInterrupt(BTN_INT),isr,CHANGE);
   // Print a message to the LCD.
   Serial.println(PROGRAM);
 #ifdef LOG_TO_SERIAL
@@ -54,49 +61,56 @@ void setup(){
 }
 
 void isr(){
-  states[0] = !digitalRead(14);
-  states[1] = !digitalRead(15);
-  states[2] = !digitalRead(16);
-  states[3] = !digitalRead(17);
-
-  states[4] = !digitalRead(18);
-  states[5] = !digitalRead(19);
-  states[6] = !(analogRead(20)>200);
-  states[7] = !(analogRead(21)>200);
+  raw_states[0] = analogRead(14)<400;
+  raw_states[1] = analogRead(15)<400;
+  raw_states[2] = analogRead(16)<400;
+  raw_states[3] = analogRead(17)<400;
+
+  raw_states[4] = analogRead(18)<400;
+  raw_states[5] = analogRead(19)<400;
+  raw_states[6] = analogRead(20)<400;
+  raw_states[7] = analogRead(21)<400;
 #ifdef LOG_TO_SERIAL
   for (int i=0;i<8;i++){
-    Serial.print(" "); Serial.print(states[i]); Serial.print(" ");
+    Serial.print(" ");
+    Serial.print(raw_states[i]);
+    Serial.print(" ");
   }
   Serial.println();
 #endif
 }
 
+void send(int btn, long duration){
+  String s = "{nano:"+String(ID)+",btn:"+String(btn)+",ms:"+String(duration)+"}";
 #ifdef SEND_485
-void send(int btn){
-  String s = "{nano:"+String(ID)+",btn:"+String(btn)+"}";
   for (int i = 0; i<10; i++){
     if (send485(s.c_str())) break;
     Serial.println("collision detected, trying again:");
   }
-}
+#else
+  Serial.println(s);
 #endif
+}
 
 void loop(){
   unsigned long now = micros();
   boolean pause = true;
   for (int i=0;i<8;i++){
-    if (states[i]){
-      if (pause){
-        delay(5);
-        pause=false;
-      }
-      if (now - times[i] > TRESHOLD){
-#ifdef SEND_485
-        send(i+1);
-#endif
-        times[i] = now;
-      }
-      states[i] = 0;
+    // we emulate a capacitor:
+    // when the button is pressed, it slowly loads, if the button is released, it unloads.
+    capacitor[i] = raw_states[i] ? capacitor[i]+1 : capacitor[i]>>1;
+
+    // if the capacitor reaches a certain treshold, the state is changed
+    boolean new_state = capacitor[i]>TRESHOLD;
+
+    // TODO: drop state after a maximum HIGH time
+
+    // when the state changes, the duration of the last state is calculated
+    if (states[i] != new_state){      
+      long diff = (now - times[i])/1000;
+      times[i] = now;
+      if (states[i]) send(i+1,diff); // old state was HIGH → we are going LOW
+      states[i] = new_state;
     }
   }
 }