ATtiny 85 to trigger Canon camera using IR LEDs and laser tripwire

Projects General Guidance
4

MichaelMeissner:
If I recall the IR protocol, it flashes the IR light for precise periods. It might be the library you are using is tuned towards 16Mhz, and perhaps you are running the ATtiny85 at a different speed like 8Mhz or 20Mhz.

Ah yes of course, I am running the ATtiny at 8Mhz! The code for the library shows this to fire the Canon camera:

void Canon::shutterNow()
{
 for(int i=0; i<16; i++) { 
    digitalWrite(_pin, HIGH);
    delayMicroseconds(11);
    digitalWrite(_pin, LOW);
    delayMicroseconds(11);
  } 
  delayMicroseconds(7330); 
  for(int i=0; i<16; i++) { 
    digitalWrite(_pin, HIGH);
    delayMicroseconds(11);
    digitalWrite(_pin, LOW);
    delayMicroseconds(11);
  }
}

Does the delayMicroseconds() function depend on the speed that chip is running at then I assume? Would I be safe enough in just halving all the times to get the same effect without having to use a crystal do you reckon?

johnwasser:
Your schematic shows a transistor grounding the cathode of a diode connected directly to Vcc. Is that the yellow LED? Shouldn't there be a current limiting resistor somewhere in there?

It is a yellow LED that I just used to visually test if the rest of the circuit was working, but you're right I should have had a resistor in there really! My bad.

Thanks for your help!