Making an ultrasonic Sensor Trigger an LCD screen

Projects Programming
1

Im trying to make a program, that when someone gets close and triggers the ultrasonic sensor, it sends power/turns on an lcd screen, but I keep getting errors.

Here is the full error message and attached is the code so far if anyone can please help me.

In function 'void setup()':

Final:56:18: error: 'trigger_pin' was not declared in this scope

pinMode (trigger_pin, OUTPUT);

^~~~~~~~~~~

Final:58:18: error: 'echo_pin' was not declared in this scope

pinMode (echo_pin, INPUT);

^~~~~~~~

Final:60:18: error: 'buzzer_pin' was not declared in this scope

pinMode (buzzer_pin, OUTPUT);

^~~~~~~~~~
In function 'void loop()':

Final:68:17: error: 'trigger_pin' was not declared in this scope

digitalWrite (trigger_pin, HIGH);

^~~~~~~~~~~

Final:74:5: error: 'time' was not declared in this scope

time = pulseIn (echo_pin, HIGH);

^~~~

74:5: note: suggested alternative: 'tone'

time = pulseIn (echo_pin, HIGH);

^~~~

tone

Final:74:21: error: 'echo_pin' was not declared in this scope

time = pulseIn (echo_pin, HIGH);

^~~~~~~~

Final:76:5: error: 'distance' was not declared in this scope

distance = (time * 0.034) / 2;

^~~~~~~~

note: suggested alternative: 'isSpace'

distance = (time * 0.034) / 2;

^~~~~~~~

isSpace

Final:90:23: error: 'buzzer_pin' was not declared in this scope

digitalWrite (buzzer_pin, HIGH);

^~~~~~~~~~

Final:104:23: error: 'buzzer_pin' was not declared in this scope

digitalWrite (buzzer_pin, LOW);

^~~~~~~~~~

Sensor:14:16: error: a function-definition is not allowed here before '{' token

void setup ( ) {

^

Sensor:32:15: error: a function-definition is not allowed here before '{' token

void loop ( ) {

^

Sensor:76:3: error: expected '}' at end of input

}

^

exit status 1
'trigger_pin' was not declared in this scope

Final_help.ino (1.16 KB)

2

Yes, as the compiler is telling you, you have not defined any ultrasonic module control pins or a buzzer output pin. How would the program know which ones they are, otherwise?

Here is how one of them could look:

const int buzzer_pin = 5;

That would work if your buzzer is connected to Arduino digital pin 5.