I should mention that the 470R should be 1/4 watt or larger, carbon composition or thick film. Beware: it will quickly burn up if your trigger software ever makes a sustained output instead of pulses. If your software could apply 24V steady to the resistor, use a 2 watt resistor.
A 1/4 watt resistor will be operating at a low duty cycle, above its ratings. Thick film and carbon comp can handle surges, but a thin film resistor won't last long in this circuit.