byte digit0 = 10;
byte digit1 = 11;
int clipdrum = 12;
int clip18 = 13;
int clip12 = A0;
int clip6 = A1;
int firepin = A2;
int photosensor = A4;
int triggersignal = A5;
int resetpin = 9;
int counter = 0;
int AmmoCount = 0;
int buttonState = 0;
int lastButtonState = 0;
byte sevenSegmentPins[] = {2,3,4,5,6,7,8};
byte sevenSegment[10][7] =
{
//a b c d e f g
{ 0,0,0,0,0,0,1 }, // = 0
{ 1,0,0,1,1,1,1 }, // = 1
{ 0,0,1,0,0,1,0 }, // = 2
{ 0,0,0,0,1,1,0 }, // = 3
{ 1,0,0,1,1,0,0 }, // = 4
{ 0,1,0,0,1,0,0 }, // = 5
{ 0,1,0,0,0,0,0 }, // = 6
{ 0,0,0,1,1,1,1 }, // = 7
{ 0,0,0,0,0,0,0 }, // = 8
{ 0,0,0,1,1,0,0 } // = 9
};
void setup()
{
Serial.begin(9600);
pinMode(digit0, OUTPUT); //pin 10
pinMode(digit1, OUTPUT); //pin 11
pinMode(clipdrum, INPUT); //pin 12
pinMode(clip18, INPUT); //pin 13
pinMode(clip12, INPUT); //pin 14
pinMode(clip6, INPUT); //pin 15
pinMode(firepin, INPUT); //pin 16
pinMode(resetpin, INPUT); //pin 9
pinMode(photosensor, INPUT); // Light Trigger
pinMode(triggersignal, OUTPUT);// Signal To Light Trigger
for(int i=0; i<7; i++)
{
pinMode(sevenSegmentPins[i], OUTPUT);
}
digitalWrite(digit0, HIGH);
digitalWrite(digit1, HIGH);
}
void segmentWrite(byte digit)
{
byte pin = 2;
for (byte i=0; i<7; ++i)
{
digitalWrite(pin, sevenSegment[digit][i]);
++pin;
}
}
void loop()
{
Serial.println(analogRead(photosensor));
AmmoCount = 0;
digitalWrite(digit0, HIGH);
segmentWrite(0);
delay(10);
digitalWrite(digit0, LOW);
digitalWrite(digit1, HIGH);
segmentWrite(0);
delay(10);
digitalWrite(digit1, LOW);
if (digitalRead(clipdrum) == HIGH)
{
AmmoCount = 25;
digitalWrite(digit0, LOW);
segmentWrite(AmmoCount%10);
delay(10);
digitalWrite(digit0, HIGH);
digitalWrite(digit1, LOW);
segmentWrite(AmmoCount/10);
delay(10);
digitalWrite(digit1, HIGH);
while(digitalRead(clipdrum) == HIGH){
buttonState = analogRead(photosensor) < 700;
if (buttonState != lastButtonState && buttonState == HIGH && AmmoCount>0) {
AmmoCount -= 1;
}
lastButtonState = buttonState;
digitalWrite(digit0, LOW);
segmentWrite(AmmoCount%10);
delay(10);
digitalWrite(digit0, HIGH);
digitalWrite(digit1, LOW);
segmentWrite(AmmoCount/10);
delay(10);
digitalWrite(digit1, HIGH);
}
}
else if (digitalRead(clip18) == HIGH)
{
AmmoCount = 18;
digitalWrite(digit0, LOW);
segmentWrite(AmmoCount%10);
delay(10);
digitalWrite(digit0, HIGH);
digitalWrite(digit1, LOW);
segmentWrite(AmmoCount/10);
delayMicroseconds(100);
digitalWrite(digit1, HIGH);
while(digitalRead(clip18) == HIGH){
buttonState = analogRead(photosensor) < 700;
if (buttonState != lastButtonState && buttonState == HIGH && AmmoCount>0) {
AmmoCount -= 1;
}
lastButtonState = buttonState;
digitalWrite(digit0, LOW);
segmentWrite(AmmoCount%10);
delay(10);
digitalWrite(digit0, HIGH);
digitalWrite(digit1, LOW);
segmentWrite(AmmoCount/10);
delay(10);
digitalWrite(digit1, HIGH);
}
}
else if (digitalRead(clip12) == HIGH)
{
AmmoCount = 12;
digitalWrite(digit0, LOW);
segmentWrite(AmmoCount%10);
delay(10);
digitalWrite(digit0, HIGH);
digitalWrite(digit1, LOW);
segmentWrite(AmmoCount/10);
delay(10);
digitalWrite(digit1, HIGH);
while(digitalRead(clip12) == HIGH){
buttonState = analogRead(photosensor) < 700;
if (buttonState != lastButtonState && buttonState == HIGH && AmmoCount>0) {
AmmoCount -= 1;
}
lastButtonState = buttonState;
digitalWrite(digit0, LOW);
segmentWrite(AmmoCount%10);
delay(10);
digitalWrite(digit0, HIGH);
digitalWrite(digit1, LOW);
segmentWrite(AmmoCount/10);
delay(10);
digitalWrite(digit1, HIGH);
}
}
else if (digitalRead(clip6)== HIGH)
{
AmmoCount = 6;
digitalWrite(digit0, LOW);
segmentWrite(AmmoCount%10);
delay(10);
digitalWrite(digit0, HIGH);
digitalWrite(digit1, LOW);
segmentWrite(AmmoCount/10);
delay(10);
digitalWrite(digit1, HIGH);
while(digitalRead(clip6) == HIGH){
buttonState = analogRead(photosensor) < 700;
if (buttonState != lastButtonState && buttonState == HIGH && AmmoCount>0) {
AmmoCount -= 1;
}
lastButtonState = buttonState;
digitalWrite(digit0, LOW);
segmentWrite(AmmoCount%10);
delay(10);
digitalWrite(digit0, HIGH);
digitalWrite(digit1, LOW);
segmentWrite(AmmoCount/10);
delay(10);
digitalWrite(digit1, HIGH);
}
}
else
{
AmmoCount = 0;
}
}
The "photosensor" is just a photoresistor from Radioshack 
![IMG_0245[1].JPG](https://europe1.discourse-cdn.com/arduino/original/3X/8/b/8bbb69380d8845e411a0bf56427c94336443b1df.jpg)