Corrected Arduino Strobe

/*
 * Shitty strobe light
 * kerai 2014
*/

// duhh I'm dumb, changed to use reciprocal of the earlier BPM division thing, whatever

//////
////// ARDUINO PART
//////

// the setup function runs once when you press reset or power the board
void setup() {
  // initialize digital pin 13 as an output.
  pinMode(12, OUTPUT);
  Serial.begin(115200);
}

typedef unsigned long MicroCounter;

MicroCounter delay_sync_time=0;
MicroCounter delay_period=100;

#define MICROSECONDS_IN_ONE_SECOND_F 1000000.f

// the loop function runs over and over again forever
void loop() {
  if(Serial.available()){
    byte bpm = Serial.read();
    Serial.print(bpm, DEC);
    Serial.println("bpm");
    float bpmf = (float) bpm;
   delay_period = (unsigned) MICROSECONDS_IN_ONE_SECOND_F * (60.f / bpmf);

    delay_sync_time = micros();
  }
  MicroCounter time = micros();
  MicroCounter delta = time - delay_sync_time;
  if(delta > delay_period){
    delay_sync_time += delta;
    digitalWrite(12,!digitalRead(12));
  }
}

//////
////// UNIX PART
//////

#include <stdio.h>
#include <stdint.h>

int main(void){
    fprintf(stderr, "Enter number: ");
    unsigned bpm=0;
    scanf("%u", &bpm);
    uint8_t byte_bpm = (uint8_t) bpm;
    fprintf(stderr, "Got %u, byte value %hhu\n", bpm, byte_bpm);
    fwrite(&byte_bpm,1,1,stdout);
}

//////
////// How to use
//////
/*
Put code on arduino.

Open up a shell, compile dec_number_to_bin.c

./dec_number_bin > /dev/ttyACM0

Follow prompt, etc.

Written drunk, it works somehow, you're on your own synchronising it to audio.*/