commit 07d67fb0ae06b8717b6bef319818d9fa5f25a2e5
Author: sirlilpanda <sirlilpanda@gmail.com>
Date:   Mon Feb 23 17:04:19 2026 +1300

    init

diff --git a/delay_line.scad b/delay_line.scad
new file mode 100644
index 0000000..c67bf74
--- /dev/null
+++ b/delay_line.scad
@@ -0,0 +1,481 @@
+// inputs, delay line config
+// will have to scale approperly
+$fa = 1;
+$fs = 0.01;
+
+SCRIPT_VERSION="0.0.1";
+FONT="Ubuntu Sans Mono:style=Regular";
+// lambda = 7.5;
+
+substrate = "SI";
+test_number = 1;
+// linbo
+c = 3992.0;
+// si
+// c = 3159.0;
+freq = 50.0e6;
+
+// $fs = (c/freq);
+
+// inout distance
+distance = 50;
+
+// number of finger
+n_fingers = 50;
+
+// should be 50-70
+finger_length = 60; 
+
+// for tweaking the design
+gap = 0;
+
+// for tweaking the design
+thickness = 0;
+
+// scale in m
+scale_unit = 1e3;
+
+leg_length = 0.003;
+leg_width = 0.00001875;
+leg_angle = 10;
+size = 0.002;
+bond_pad_shape = "square";
+
+
+info_block_offset_x=7;
+info_block_offset_y=30;
+info_block_scale=0.3;
+title_text_size = 4;
+prop_text_size = 2.5;
+id_text_size = 2;
+
+number_of_idts_per_quadrent=4;
+idt_x_spacing = 10;
+idt_y_spacing = 7;
+
+wafer_size_inch = 4;
+
+function length(point_1, point_2) = sqrt(
+    (point_1-point_2).x^2 +
+    (point_1-point_2).y^2 +
+    (point_1-point_2).z^2
+);
+
+
+// creates 1 side of the idt
+module delay_line(lambda = 1, n_fingers = 1, finger_length = 50, gap = 0, thickness = 0) {
+    // code
+    l45 =lambda*5/4;
+    l2 = lambda/2;
+    l4 = lambda/4;
+    l8 = lambda/8;
+    b = l4 + thickness;
+    f = l4 + finger_length*lambda;
+
+    points_cap = [
+        [0, 0],
+        [0, l2],
+        [-b-f, l2],
+        [-b-f, l4],
+        [-b, l4],
+        [-b, 0]
+    ];
+
+    points = [
+        [0, 0],
+        [b, 0],
+        [b, l2],
+        [b+f, l2],
+        [b+f, l2+l4],
+        [b, l2+l4],
+        [b, l4*5-l4],
+        [0, l4*5-l4]
+    ];
+    // union () {
+
+    translate([0, l2, 0]){
+            for(i = [0:n_fingers]){
+                translate([0, i*(l45-l4), 0]) {
+                polygon(points);
+                }
+            }
+
+        color("red") {
+            rotate([0, 0, 180])
+            translate([0, 0, 0]) {
+                polygon(points_cap);
+            }
+
+            translate([f+l2+gap+thickness, -l2, 0]) {
+                square(size=[l4+thickness, l4]);
+            }
+        }
+
+        
+            union() {
+                for(i = [0:n_fingers]){
+                    translate([2*b+f+gap+l4, i*(l45-l4)+l2+l4 , 0]) 
+                    rotate([0, 0, 180])
+                    polygon(points);
+                }
+            }
+        
+        color("red") {
+            translate([2*b+f+gap+l4, n_fingers*lambda+lambda-l4, 0]) {
+                polygon(points_cap);
+            }
+            translate([0, n_fingers*lambda+lambda, 0]) {
+                square(size=[l4+thickness, l4]);
+            }
+        }
+
+    }
+}
+
+
+// todo fix this
+// units in m, the size is the min bond pad size
+module bond_pad(
+    leg_length = 0.000075, 
+    leg_width = 0.00001875,
+    leg_length_tweak = 0,
+    leg_angle = 45, 
+    size = 0.000075, 
+    bond_pad_shape = "square", 
+    post_scale = false
+) {
+    if (post_scale) {
+        circle(r=leg_width*post_scale);
+
+        rotate([0, 0, leg_angle+180]) {
+            translate([-leg_length*post_scale-leg_length_tweak, -leg_width*post_scale/2, 0]) {
+                // color([0, 255/255, 255/255]) {
+                    // arm
+                    square(size=[(leg_length)*post_scale+leg_length_tweak, leg_width*post_scale]);                
+                // }
+            }
+        }
+        // pad
+        translate([post_scale*leg_length*cos(leg_angle), post_scale*leg_length*sin(leg_angle), 0]) {
+            square(size=[size*post_scale, size*post_scale], center=true);
+        }
+
+        // echo(str("x = ", post_scale*leg_length*cos(leg_angle+180)));
+        // echo(str("y = ", post_scale*leg_length*sin(leg_angle+180)));
+
+    
+    } else {
+        rotate([0, 0, leg_angle+180]) {
+            translate([-leg_length/2, -leg_width, 0]) {
+                // color([0, 255/255, 255/255]) {
+                    square(size=[leg_length, leg_width]);                
+                // }
+            }
+        }
+        square(size=[size, size], center=true);
+    }
+}
+
+// creates the input and output ids
+module delay_line_idt(
+    c, 
+    f, 
+    n_fingers, 
+    distance = 100, 
+    finger_length = 50, 
+    gap = 0, 
+    thickness = 0, 
+    impedance = 50, 
+    has_bond_pads = false,
+    bond_pad_leg_length = 0.00005, 
+    bond_pad_leg_width = 0.00001875, 
+    bond_pad_size = 0.000075,
+    bond_pad_angle = 45,
+    bond_pad_bond_pad_shape = "square",
+    post_scale = false,
+    id_number = 0,
+    has_id = true
+) {
+
+    local_scale = 0;
+    // echo("===== DELAY LINE IDT INFO ===== ");
+
+    if (post_scale) {
+        lambda = c/f * post_scale;
+        // dont worry about these magic fractions
+        length_of_input = n_fingers*lambda+1.74*lambda;
+        // n_fingers*lambda+lambda/2;
+        
+        
+        echo(str("lambda = ", lambda));
+        // echo(str("lambda/4 = ", lambda/4));
+        // echo(str("lambda_scale = ", post_scale));
+        delay_line(lambda, n_fingers, finger_length, gap, thickness);
+
+
+
+        if (has_id) {
+            color([255/255, 0/255, 255/255]) 
+            translate([finger_length*lambda/2, has_bond_pads ? -(bond_pad_leg_length * post_scale * cos(bond_pad_angle)) : -lambda*finger_length/2, 0])
+            text(str(id_number), size=id_text_size, halign="center");
+        }
+
+        color([0/255, 255/255, 128/255]) {
+            translate([0, distance*lambda+length_of_input, 0]) {
+                delay_line(lambda, n_fingers, finger_length, gap, thickness);
+            }
+        }
+
+        // near ori
+        rotate([0, 0, -90]) {
+            if (has_bond_pads) {
+                color([255/255, 255/255, 255/255]) {
+                    bond_pad(
+                        leg_length_tweak = lambda/4,
+                        leg_width=c/f/4, 
+                        leg_length=length(
+                            [0,0,0], 
+                            [bond_pad_leg_length, bond_pad_leg_length, 0]
+                        ), 
+                        leg_angle = -bond_pad_angle,
+                        size = bond_pad_size, 
+                        post_scale=scale_unit
+                    );
+                }
+            }
+        }
+        // near side
+        
+        translate([lambda*finger_length+gap+thickness*2+lambda, 0, 0]) {
+            rotate([0, 0, -90]) {
+                    if (has_bond_pads) {
+                        bond_pad(
+                            leg_length_tweak = lambda/5,
+                            leg_width=c/f/4, 
+                            leg_length=length(
+                                [0,0,0], 
+                                [bond_pad_leg_length, bond_pad_leg_length, 0]
+                            ), 
+                            leg_angle = bond_pad_angle,
+                            size = bond_pad_size, 
+                            post_scale=scale_unit
+                        );
+                }
+            }
+        }
+
+        // far side
+        translate([0, length_of_input+distance*lambda+length_of_input, 0]) {   
+                rotate([0, 0, 90]) {                    
+                    if (has_bond_pads) {
+                        bond_pad(
+                            leg_length_tweak = lambda/5,
+                            leg_width=c/f/4, 
+                            leg_length=length(
+                                [0,0,0], 
+                                [bond_pad_leg_length, bond_pad_leg_length, 0]
+                            ), 
+                            leg_angle = bond_pad_angle,
+                            size = bond_pad_size, 
+                            post_scale=scale_unit
+                        );
+                    }
+                }
+                // furthest side
+                translate([lambda*finger_length+gap+thickness*2+lambda, 0, 0]) {
+                    rotate([0, 0, 90]) {                    
+                            if (has_bond_pads) {
+                                bond_pad(
+                                    leg_length_tweak = lambda/4,
+                                    leg_width=c/f/4, 
+                                    leg_length=length(
+                                        [0,0,0], 
+                                        [bond_pad_leg_length, bond_pad_leg_length, 0]
+                                    ), 
+                                    leg_angle = -bond_pad_angle,
+                                    size = bond_pad_size, 
+                                    post_scale=scale_unit
+                                );
+                        }
+                    }
+                }
+        } 
+    } else {
+        lambda = 1;
+        length_of_input = n_fingers*lambda*15/8;
+        echo(str("lambda = ", lambda));
+        echo(str("lambda_scale = ", 1));
+        delay_line(lambda, n_fingers, finger_length, gap, thickness);
+        translate([0, length_of_input+distance*lambda, 0])
+        delay_line(lambda, n_fingers, finger_length, gap, thickness);
+    }
+
+    // echo(str("impedance = ", impedance));
+
+    // echo(str("total capacitance = ", 1/(2*PI*f*impedance)));
+
+    // echo("===== DELAY LINE IDT INFO ===== ");
+}
+
+module wafer(d) {
+    color([128/255, 128/255, 128/255]) {
+        translate([0, 0, -1]) {
+            circle(r=d/2);
+        }
+    }
+}
+
+module prameter_text() {
+text(str("IDT ", substrate, "#", test_number), size=4, font=FONT);
+translate([0, -title_text_size, 0])    
+text(str("c              : ", c), size=prop_text_size, font=FONT);
+translate([0, -title_text_size*2, 0])    
+text(str("freq           : ", freq), size=prop_text_size, font=FONT);
+translate([0, -title_text_size*3, 0])    
+text(str("distance       : ", distance), size=prop_text_size, font=FONT);
+translate([0, -title_text_size*4, 0])    
+text(str("n_fingers      : ", n_fingers), size=prop_text_size, font=FONT);
+translate([0, -title_text_size*5, 0])    
+text(str("finger_length  : ", finger_length), size=prop_text_size, font=FONT);
+translate([0, -title_text_size*6, 0])    
+text(str("gap            : ", gap), size=prop_text_size, font=FONT);
+translate([0, -title_text_size*7, 0])    
+text(str("thickness      : ", thickness), size=prop_text_size, font=FONT);
+translate([0, -title_text_size*8, 0])    
+text(str("leg_length     : ", leg_length), size=prop_text_size, font=FONT);
+translate([0, -title_text_size*9, 0])    
+text(str("leg_angle      : ", leg_angle), size=prop_text_size, font=FONT);
+translate([0, -title_text_size*10, 0])    
+text(str("size           : ", size), size=prop_text_size, font=FONT);
+translate([0, -title_text_size*11, 0])    
+text(str("feat. size (mm): ", (c/freq)*1e3), size=prop_text_size, font=FONT);
+translate([0, -title_text_size*12, 0])    
+text(str("version        : ", SCRIPT_VERSION), size=prop_text_size, font=FONT);
+
+}
+
+
+
+translate([info_block_offset_x, -info_block_offset_y, 0]) {
+rotate([0, 0, -90]) 
+scale([info_block_scale, info_block_scale, info_block_scale]) {
+    prameter_text();
+}
+}
+
+rotate([0, 0, 180])
+translate([info_block_offset_x, -info_block_offset_y, 0]) {
+rotate([0, 0, -90]) 
+scale([info_block_scale, info_block_scale, info_block_scale]) {
+    prameter_text();
+}
+}
+
+// delay_line_idt(
+//     c, 
+//     freq, 
+//     n_fingers, 
+//     distance, 
+//     finger_length, 
+//     gap, 
+//     thickness, 
+//     post_scale=scale_unit,
+//     has_bond_pads = true,
+//     bond_pad_angle = leg_angle,
+//     bond_pad_leg_width = leg_width,
+//     bond_pad_leg_length = leg_length,
+//     bond_pad_size = size 
+// );
+
+
+// wafer(wafer_size_inch*25.4);
+for (i=[0:number_of_idts_per_quadrent-1]) {
+    translate([idt_x_spacing/4, 0, 0]) {
+    translate([i * idt_x_spacing, idt_y_spacing, 0]) {
+            delay_line_idt(
+                c, 
+                freq, 
+                n_fingers, 
+                distance, 
+                finger_length, 
+                gap, 
+                thickness, 
+                post_scale=scale_unit,
+                has_bond_pads = true,
+                bond_pad_angle = leg_angle,
+                bond_pad_leg_width = leg_width,
+                bond_pad_leg_length = leg_length,
+                bond_pad_size = size 
+            );
+    }
+    translate([i * idt_x_spacing, -idt_y_spacing, 0]) {
+        scale([1, -1, 1]) {
+            delay_line_idt(
+                c, 
+                freq, 
+                n_fingers, 
+                distance, 
+                finger_length, 
+                gap, 
+                thickness, 
+                post_scale=scale_unit,
+                has_bond_pads = true,
+                bond_pad_angle = leg_angle,
+                bond_pad_leg_width = leg_width,
+                bond_pad_leg_length = leg_length,
+                bond_pad_size = size 
+            );
+        }
+    }
+    }
+
+    scale([-1, 1, 1])
+    translate([idt_x_spacing/4, 0, 0]) {
+        
+    translate([i * idt_x_spacing, idt_y_spacing, 0]) {
+            delay_line_idt(
+                c, 
+                freq, 
+                n_fingers, 
+                distance, 
+                finger_length, 
+                gap, 
+                thickness, 
+                post_scale=scale_unit,
+                has_bond_pads = true,
+                bond_pad_angle = leg_angle,
+                bond_pad_leg_width = leg_width,
+                bond_pad_leg_length = leg_length,
+                bond_pad_size = size 
+            );
+    }
+    translate([i * idt_x_spacing, -idt_y_spacing, 0]) {
+        scale([1, -1, 1]) {
+            delay_line_idt(
+                c, 
+                freq, 
+                n_fingers, 
+                distance, 
+                finger_length, 
+                gap, 
+                thickness, 
+                post_scale=scale_unit,
+                has_bond_pads = true,
+                bond_pad_angle = leg_angle,
+                bond_pad_leg_width = leg_width,
+                bond_pad_leg_length = leg_length,
+                bond_pad_size = size 
+            );
+        }
+    }
+    }
+}
+
+// bond_pad(
+//     leg_length = 0.0075, 
+//     leg_width = 0.00001875,
+//     leg_angle = 20, 
+//     size = 0.0075, 
+//     bond_pad_shape = "square", 
+//     post_scale = scale_unit
+// );
\ No newline at end of file