diff --git a/latex/latex_math/symbols.pdf b/latex/latex_math/symbols.pdf
new file mode 100644
index 0000000..0de64b6
Binary files /dev/null and b/latex/latex_math/symbols.pdf differ
diff --git a/microcontroller_lab/task4/task4.ino b/microcontroller_lab/task4/task4.ino
index 9998021..6d9a597 100644
--- a/microcontroller_lab/task4/task4.ino
+++ b/microcontroller_lab/task4/task4.ino
@@ -1,21 +1,39 @@
-#define DECODE_NEC
-#include <IRremote.hpp>;
-#include <Servo.h>
-Servo myservo;
+#define DECODE_NEC        //decode incoming ir-frames with the correct protocol being used by the ir-remote
+#include <IRremote.hpp>;  //inlcude library for easy use and implementation of the ir sensor
+#include <Servo.h>        //include library to control a servo motor
+Servo myservo;            //set up an object called servo to adress the angle-commands later
+
+int calibration;
+
 
 void setup() {
 
-IrReceiver.begin(2);
-myservo.attach(9);
+  Serial.begin(9600);   //establish serial connection for debugging purposes
+  pinMode(A0, INPUT);   //define cny70 sensor input
+  pinMode(13, OUTPUT);  //define inbuilt led as output for debugging purposes
+  IrReceiver.begin(2);  //start the ir-receiver on pin 2 of the arduino nano
+  myservo.attach(9);    //control a servo motor attached to pin 9 of the arduino nano
+  myservo.write(175);   //go to idle position after initilzing code after boot/reboot
 
 }
 
 void loop() {
 
-if (IrReceiver.decode()){
-  if (IrReceiver.decodedIRData.command == 0x45) {myservo.write(175);}
-  if (IrReceiver.decodedIRData.command == 0x46) {myservo.write(5);}
-  if (IrReceiver.decodedIRData.command == 0x47) {}
-IrReceiver.resume();}
+  if (IrReceiver.decode()){
+    if (IrReceiver.decodedIRData.command == 0x45) { myservo.write(175); }  //if button 1 of the remote is pressed, rotate servo to position 1
+    if (IrReceiver.decodedIRData.command == 0x46) { myservo.write(5); }    //if button 2 of the remote is pressed, rotate servo to position 2
+    if (IrReceiver.decodedIRData.command == 0x47) { button(); }
+    IrReceiver.resume();}
+
+  Serial.println(analogRead(A0));
 
 }
+
+void button() {
+
+for (int pos = 0, diff = 0; diff < 20; pos = pos +1){
+delay(10);
+myservo.write(pos);
+diff = calibration - analogRead(A0);}
+
+}
\ No newline at end of file