Audible 16mm Footage Counter

I modified a 16mm film synchronizer to add an audible footage counter. This helps me spool down large loads of film in the dark. Conventional wisdom says that 42 turns of the (4:1 geared) rewinds will fill a 100ft daylight spool. I was curious to see if that’s accurate. (It is.) More importantly, I can barely count without using my fingers, so why not make a robot do the work!

What I did

Cleaned the synchronizer and checked for scratches. Don’t wanna scratch the film!
Glued a magnet to one of the gangs, with a matching reed switch on the frame. Each pass of the magnet will momentarily close the reed switch. 1 pulse = 1 foot.
Mounted a handy mint box enclosure containing an Arduino with a piezo buzzer and reset button. Each foot is marked with a beep, each 10th foot with a higher beep, until finally 100ft causes a long beep at a still higher frequency. (I chose frequencies within the resonant band of the piezo to get maximum volume.)
If you are using this in the dark, remember to remove or cover the Arduino power LED! If your board has an LED on pin 13, it will flash during boot/reset, so cover that too.

How It Sounds

Arduino Code

Requires the ToneAC library
At boot/reset you’ll hear a few beeps to let you know it’s running
You can monitor the count via serial for debugging
If you uncomment the LED lines, Pin 13 will go high for odd feet & low for even feet.

```
/*
```

  Foot-counter for 16mm synchronizer, based on debounce example and ToneAC library for louder piezo.

```
  
```

  Attach a reed switch or opto sensor to the sync block for 1 pulse per foot.

```
  
```
```
  Uses toneAC library to drive piezo:
```
```
  
```

  toneAC( frequency [, volume [, length [, background ]]] ) - Play a note.

```
 
```

    frequency - Play the specified frequency indefinitely, turn off with toneAC().

    volume - [optional] Set a volume level. (default: 10, range: 0 to 10 [0 = off])

    length - [optional] Set the length to play in milliseconds. (default: 0 [forever], range: 0 to 2^32-1)

    background - [optional] Play note in background or pause till finished? (default: false, values: true/false)

```
 
```
```
toneAC() - Stop output.
```
```
 
```
```
noToneAC() - Same as toneAC().
```
```
*/
```
```
 
```

#include "toneAC.h" //This alternative library is much louder than the "tone" library, but needs specific pins (9 & 10)

```
 
```

// constants won't change. They're used here to set pin numbers:

const int buttonPin = 2;    // the number of the pushbutton pin

const int ledPin = 13;      // the number of the LED pin

```
 
```
```
// Variables will change:
```

int ledState = LOW;         // the current state of the output pin

int buttonState;             // the current reading from the input pin

int lastButtonState = LOW;   // the previous reading from the input pin

```
int feetCount = 0;
```
```
 
```

// the following variables are unsigned longs because the time, measured in

// milliseconds, will quickly become a bigger number than can be stored in an int.

unsigned long lastDebounceTime = 0;  // the last time the output pin was toggled

unsigned long debounceDelay = 5;    // the debounce time; increase if the output flickers

```
 
```
```
void setup() {
```
```
  Serial.begin(9600);
```
```
  pinMode(buttonPin, INPUT_PULLUP);
```
```
  pinMode(ledPin, OUTPUT);
```
```
 
```
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  // set initial LED state
```
```
  digitalWrite(ledPin, ledState);
```
```
 
```

  Serial.println("Footage Counter RESET");

```
 
```
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  toneAC(2300, 10, 50);
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  delay(50);
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```
  toneAC(2300, 10, 50);
```
```
  delay(50);
```
```
}
```
```
 
```
```
void loop() {
```

  // read the state of the switch into a local variable:

```
  int reading = digitalRead(buttonPin);
```
```
 
```

  // check to see if you just pressed the button

  // (i.e. the input went from LOW to HIGH), and you've waited long enough

  // since the last press to ignore any noise:

```
 
```

  // If the switch changed, due to noise or pressing:

```
  if (reading != lastButtonState) {
```
```
    // reset the debouncing timer
```
```
    lastDebounceTime = millis();
```
```
  }
```
```
 
```

  if ((millis() - lastDebounceTime) > debounceDelay) {

    // whatever the reading is at, it's been there for longer than the debounce

    // delay, so take it as the actual current state:

```
 
```
```
    // if the button state has changed:
```
```
    if (reading != buttonState) {
```
```
      buttonState = reading;
```
```
 
```

      // increment count on high-going transition of button

```
      if (buttonState == HIGH) {
```
```
        ledState = !ledState;
```

        Serial.println(String(feetCount) + " ft");

        if (feetCount % 100 == 0 && feetCount > 1) {

```
          toneAC(2500, 10, 3000);
```

        } else if (feetCount % 10 == 0 && feetCount > 1) {

```
          toneAC(2300, 10, 75);
```
```
        } else {
```
```
        toneAC(2000, 10, 20);
```
```
        }
```
```
        feetCount++;
```
```
      }
```
```
    }
```
```
  }
```
```
 
```
```
  // set the LED:
```
```
  //digitalWrite(ledPin, ledState);
```
```
 
```

  // save the reading. Next time through the loop, it'll be the lastButtonState:

```
  lastButtonState = reading;
```
```
}
```

What I did

How It Sounds

Arduino Code

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