Timers in OpenSCAD

Our first example demonstrates how to use timers in OpenSCAD. Although OpenSCAD doesn’t have built-in timer functionality like some other languages, we can simulate similar behavior using the $t special variable and animation.

// Simulate a timer using animation
$fn = 100;

module timer(duration) {
    if ($t < duration) {
        // Timer is still running
        difference() {
            circle(r = 10);
            pie_slice(a = 360 * $t / duration, r = 10);
        }
    } else {
        // Timer has fired
        text("Timer fired", size = 5);
    }
}

module pie_slice(a, r) {
    difference() {
        circle(r = r);
        if (a < 180) {
            rotate([0, 0, a])
                translate([-r, 0, 0])
                    square(r * 2);
        }
        rotate([0, 0, a])
            translate([-r, 0, 0])
                square(r * 2);
    }
}

// Main scene
translate([-20, 0, 0]) timer(0.5);  // Timer 1: 0.5 seconds
translate([20, 0, 0]) timer(1);     // Timer 2: 1 second

In this OpenSCAD script, we simulate timers using the $t special variable, which represents the current time in an animation. The timer module creates a visual representation of a timer:

1. We create two timers with different durations (0.5 seconds and 1 second).
2. The timer module draws a circle that fills up over time, simulating a timer counting down.
3. When the timer “fires” (i.e., when $t exceeds the specified duration), it displays “Timer fired”.

To run this animation:

1. Save the code in a file with a .scad extension (e.g., timers.scad).
2. Open the file in OpenSCAD.
3. To view the animation, go to “View” -> “Animate” and adjust the FPS and Steps as needed.

Note that OpenSCAD doesn’t support real-time timers or threading. This example provides a visual simulation of timers using OpenSCAD’s animation capabilities. The concept of canceling a timer before it fires, as shown in the original example, isn’t directly applicable in OpenSCAD due to its declarative nature and lack of real-time event handling.

For more complex timing or real-time operations, you might need to use OpenSCAD in combination with an external script or program that can handle timing and then generate or modify OpenSCAD code based on those timings.