Telegraph using light signal on Arduino

1const int LEDpin=10;
2const int sensorpin=A0;
3int toggleLED=0;
4int lightamount=0;
5long LEDtimer=0;
6long sensortimer=0;
7int incomingByte;
8
9void setup() {
10  // put your setup code here, to run once:
11pinMode(LEDpin,OUTPUT);
12pinMode(sensorpin,INPUT);
13Serial.begin(9600);
14}
15
16
17void loop() {
18  // put your main code here, to run repeatedly:
19if (Serial.available() > 0)
20{
21incomingByte = Serial.read();
22transmitter(incomingByte);
23
24}
25
26receiver();
27
28}
29void transmitter(int incomingByte)
30{
31if (millis() >= LEDtimer+ 1000)
32{
33  if (incomingByte == 'H')
34  {digitalWrite(LEDpin,HIGH);}
35  if (incomingByte == 'L')
36  {digitalWrite(LEDpin,LOW);}
37LEDtimer=millis();
38}
39
40
41
42}
43
44void receiver ()
45{
46if (millis()>= sensortimer+500)
47  {lightamount=analogRead(sensorpin);
48  Serial.print("light amount is :");
49  Serial.println(lightamount);
50  sensortimer=millis();}
51}