This example demonstrates how to use hardware.micros() to capture the length of a pulse on a digital input (ie - how long the pin stayed high)

pulse.device.nut

pulseStart <- 0;

function state_change()
{
    if (hardware.pin1.read())
    {
        pulseStart = hardware.micros();
    } 
    else 
    {
        server.log("Pulse on pin1 lasted " + (hardware.micros() - pulseStart) + " microseconds");
    }
}

hardware.pin1.configure(DIGITAL_IN, state_change);