Add debounce function to buttons in arduino code - button

Question

I have made a transmission controller and the code works fine as it is. But i would like to add debounce function into to the code, since the shifts would somethimes not be recognised when pushing the buttons. I am far from a good coder, so this code is very simple and I understand everything in it. But I cant figure out how to add debounce to the buttons without advancing the code too much for me too not understand it anymore.
Could anyone come with any help or tips please? See attached code.
int gear = 1;
// output pins for transistor controlled solenoids
int solA = 4;
int solB = 5;
int solC = 6;
int solD = 7;
int solE = 8;
int solTCC = 9;
int solLinePress = 10;
// input pins for up down / with pullup resistors
int gearup = 2;
int geardown = 3;
// Pin out for single 7 digit display
int a=22;
int b=23;
int c=24;
int d=25;
int e=26;
int f=27;
int g=28;
void setup() {
pinMode(solA, OUTPUT);
pinMode(solB, OUTPUT);
pinMode(solC, OUTPUT);
pinMode(solD, OUTPUT);
pinMode(solE, OUTPUT);
pinMode(solTCC, OUTPUT);
pinMode(solLinePress, OUTPUT);
pinMode(gearup, INPUT);
pinMode(geardown, INPUT);
pinMode(a, OUTPUT);
pinMode(b, OUTPUT);
pinMode(c, OUTPUT);
pinMode(d, OUTPUT);
pinMode(e, OUTPUT);
pinMode(f, OUTPUT);
pinMode(g, OUTPUT);
}
void loop() {
if(gear == -1){ // Reverse
digitalWrite(solA, 1);
digitalWrite(solB, 1);
digitalWrite(solC, 1);
digitalWrite(solD, 0);
digitalWrite(solE, 1);
digitalWrite(solTCC, 0);
digitalWrite(solLinePress, 0);
digitalWrite(a, LOW);
digitalWrite(b, LOW);
digitalWrite(c, HIGH);
digitalWrite(d, HIGH);
digitalWrite(e, HIGH);
digitalWrite(f, HIGH);
digitalWrite(g, HIGH);
}
if(gear == 0){ // Neutral
digitalWrite(solA, 1);
digitalWrite(solB, 1);
digitalWrite(solC, 1);
digitalWrite(solD, 1);
digitalWrite(solE, 1);
digitalWrite(solTCC, 0);
digitalWrite(solLinePress, 0);
digitalWrite(a, LOW);
digitalWrite(b, LOW);
digitalWrite(c, LOW);
digitalWrite(d, LOW);
digitalWrite(e, LOW);
digitalWrite(f, LOW);
digitalWrite(g, HIGH);
}
if(gear == 1){ // 1th gear
digitalWrite(solA, 1);
digitalWrite(solB, 1);
digitalWrite(solC, 0);
digitalWrite(solD, 1);
digitalWrite(solE, 1);
digitalWrite(solTCC, 0);
digitalWrite(solLinePress, 0);
digitalWrite(a, LOW);
digitalWrite(b, HIGH);
digitalWrite(c, HIGH);
digitalWrite(d, LOW);
digitalWrite(e, LOW);
digitalWrite(f, LOW);
digitalWrite(g, LOW);
}
if(gear == 2){ // 2nd Gear
digitalWrite(solA, 1);
digitalWrite(solB, 1);
digitalWrite(solC, 1);
digitalWrite(solD, 1);
digitalWrite(solE, 0);
digitalWrite(solTCC, 0);
digitalWrite(solLinePress, 0);
digitalWrite(a, HIGH);
digitalWrite(b, HIGH);
digitalWrite(c, LOW);
digitalWrite(d, HIGH);
digitalWrite(e, HIGH);
digitalWrite(f, LOW);
digitalWrite(g, HIGH);
}
if(gear == 3){ // 3rd Gear
digitalWrite(solA, 0);
digitalWrite(solB, 1);
digitalWrite(solC, 0);
digitalWrite(solD, 1);
digitalWrite(solE, 0);
digitalWrite(solTCC, 0);
digitalWrite(solLinePress, 0);
digitalWrite(a, HIGH);
digitalWrite(b, HIGH);
digitalWrite(c, HIGH);
digitalWrite(d, HIGH);
digitalWrite(e, LOW);
digitalWrite(f, LOW);
digitalWrite(g, HIGH);
}
if(gear == 4){ // 4th Gear
digitalWrite(solA, 0);
digitalWrite(solB, 1);
digitalWrite(solC, 1);
digitalWrite(solD, 0);
digitalWrite(solE, 0);
digitalWrite(solTCC, 0);
digitalWrite(solLinePress, 0);
digitalWrite(a, LOW);
digitalWrite(b, HIGH);
digitalWrite(c, HIGH);
digitalWrite(d, LOW);
digitalWrite(e, LOW);
digitalWrite(f, HIGH);
digitalWrite(g, HIGH);
}
if(gear == 5){ // 5th Gear
digitalWrite(solA, 0);
digitalWrite(solB, 1);
digitalWrite(solC, 0);
digitalWrite(solD, 0);
digitalWrite(solE, 1);
digitalWrite(solTCC, 0);
digitalWrite(solLinePress, 0);
digitalWrite(a, HIGH);
digitalWrite(b, LOW);
digitalWrite(c, HIGH);
digitalWrite(d, HIGH);
digitalWrite(e, LOW);
digitalWrite(f, HIGH);
digitalWrite(g, HIGH);
}
if(gear == 6){ / // 6th Gear
digitalWrite(solA, 0);
digitalWrite(solB, 0);
digitalWrite(solC, 0);
digitalWrite(solD, 0);
digitalWrite(solE, 0);
digitalWrite(solTCC, 0);
digitalWrite(solLinePress, 0);
digitalWrite(a, HIGH);
digitalWrite(b, LOW);
digitalWrite(c, HIGH);
digitalWrite(d, HIGH);
digitalWrite(e, HIGH);
digitalWrite(f, HIGH);
digitalWrite(g, HIGH);
}
if(gear == 7){ // 7th Gear
digitalWrite(solA, 1);
digitalWrite(solB, 0);
digitalWrite(solC, 0);
digitalWrite(solD, 0);
digitalWrite(solE, 1);
digitalWrite(solTCC, 0);
digitalWrite(solLinePress, 0);
digitalWrite(a, HIGH);
digitalWrite(b, HIGH);
digitalWrite(c, HIGH);
digitalWrite(d, LOW);
digitalWrite(e, LOW);
digitalWrite(f, LOW);
digitalWrite(g, LOW);
}
if(gear == 8){ // 8th Gear
digitalWrite(solA, 1);
digitalWrite(solB, 0);
digitalWrite(solC, 1);
digitalWrite(solD, 0);
digitalWrite(solE, 0);
digitalWrite(solTCC, 0);
digitalWrite(solLinePress, 0);
digitalWrite(a, HIGH);
digitalWrite(b, HIGH);
digitalWrite(c, HIGH);
digitalWrite(d, HIGH);
digitalWrite(e, HIGH);
digitalWrite(f, HIGH);
digitalWrite(g, HIGH);
}
//takes care of gear switching
delay(150); //delay to prevent going through gears too quick from holding the button or pressing too long
gear += digitalRead(geardown) - digitalRead(gearup); // non debounced! But may not be a problem because of the delay by gear change
if(gear < -1) gear = -1;
if(gear > 8) gear = 8;
//limits to actual gearset
}

Answer 1

Because the question asks specifically about how to debounce i will link you here to the official arduino example that is also contained in the IDE, libraries exist online with a brief search i found this one and you could also hardware debounce the inputs using resistors and capacitors.