// ============================================================
// miniRobo EP2 — MG90S Pan-Tilt Camera Head
// Three printed parts driven by two MG90S metal-gear servos.
// Units: millimeters.  minirobo.io
//
// Set `part` to export one piece at a time for printing:
//   "base" | "yoke" | "tilt" | "all"
// The MG90S shares the SG90 footprint, so these pockets fit
// either — but build with the metal-gear MG90S.
// ============================================================

part = "all";          // "base" | "yoke" | "tilt" | "all"
$fn = 48;

// ---------- Fit / hardware ----------
fit_tol      = 0.4;    // clearance around servo bodies (0.2 tight, 0.5 loose)
wall         = 2.4;
screw_m2     = 2.2;    // M2 clearance hole
horn_screw   = 1.8;    // self-tapper pilot into servo horn

// ---------- MG90S nominal dimensions ----------
mg90s_body_l  = 22.8;
mg90s_body_w  = 12.2;
mg90s_body_h  = 22.5;
mg90s_tab_l   = 32.0;
mg90s_tab_t   = 2.5;
mg90s_tab_z   = 16.0;
mg90s_hole_sp = 28.0;
mg90s_shaft_dx= 6.0;
mg90s_shaft_d = 5.0;
horn_r        = 7.0;
horn_screws   = 4;

// ============================================================
// SHARED MODULES
// ============================================================

// Negative volume of an MG90S standing with its shaft pointing +Z.
module mg90s_negative() {
    tol = fit_tol;
    translate([-(mg90s_body_l+tol)/2, -(mg90s_body_w+tol)/2, 0])
        cube([mg90s_body_l+tol, mg90s_body_w+tol, mg90s_body_h+1]);
    translate([-(mg90s_tab_l+tol)/2, -(mg90s_body_w+tol)/2, mg90s_tab_z])
        cube([mg90s_tab_l+tol, mg90s_body_w+tol, mg90s_tab_t+tol]);
    for (x = [-mg90s_hole_sp/2, mg90s_hole_sp/2])
        translate([x, 0, -1]) cylinder(d = screw_m2, h = mg90s_body_h + 6);
    translate([mg90s_shaft_dx, 0, mg90s_body_h - 1])
        cylinder(d = 9, h = 12);
}

// Round-horn mounting boss: center bore + ring of pilot holes.
module horn_mount(boss_d = 18, boss_t = wall + 1) {
    difference() {
        cylinder(d = boss_d, h = boss_t);
        translate([0,0,-1]) cylinder(d = mg90s_shaft_d + 1.5, h = boss_t + 2);
        for (i = [0 : horn_screws - 1])
            rotate([0,0, i * 360 / horn_screws])
                translate([horn_r, 0, -1]) cylinder(d = horn_screw, h = boss_t + 2);
    }
}

// ============================================================
// PART 1 — BASE PLATE (holds pan servo upright, shaft up)
// ============================================================
module base_plate() {
    base_l = 46; base_w = 34;
    base_h = mg90s_tab_z + mg90s_tab_t + 2;
    chassis_hole_sp = 38;

    difference() {
        hull() for (x = [-1,1], y = [-1,1])
            translate([x*(base_l/2 - 4), y*(base_w/2 - 4), 0]) cylinder(r = 4, h = base_h);
        translate([0, 0, base_h - mg90s_body_h]) mg90s_negative();
        for (x = [-chassis_hole_sp/2, chassis_hole_sp/2])
            translate([x, 0, -1]) {
                cylinder(d = screw_m2, h = base_h + 2);
                translate([0,0, base_h - 1.6]) cylinder(d1 = screw_m2, d2 = 4.5, h = 1.8);
            }
        translate([0,0,-1]) cube([mg90s_body_l+fit_tol, mg90s_body_w+fit_tol+8, 2.2], center = true);
    }
}

// ============================================================
// PART 2 — PAN YOKE (clips to pan horn, carries tilt servo)
// ============================================================
module pan_yoke() {
    plate_d  = 26;
    arm_h    = mg90s_body_h + 6;
    arm_w    = mg90s_body_w + 2*wall + fit_tol;
    wall_gap = mg90s_body_w + fit_tol;

    union() {
        difference() {
            cylinder(d = plate_d, h = wall);
            translate([0,0,-0.1]) horn_mount();
        }
        for (s = [-1, 1])
            translate([s * (wall_gap/2 + wall/2), 0, 0])
                difference() {
                    translate([-wall/2, -arm_w/2 + wall, 0])
                        cube([wall, mg90s_body_l + 2*wall, arm_h]);
                    translate([0, mg90s_hole_sp/2, arm_h - mg90s_body_l/2])
                        rotate([0,90,0]) cylinder(d = screw_m2, h = wall*3, center = true);
                    translate([0, -mg90s_hole_sp/2 + mg90s_body_l, arm_h - mg90s_body_l/2])
                        rotate([0,90,0]) cylinder(d = screw_m2, h = wall*3, center = true);
                }
    }
}

// ============================================================
// PART 3 — TILT BRACKET (clips to tilt horn, holds camera)
// ============================================================
module tilt_bracket() {
    plate_l = 30; plate_w = 26;
    cam_hole_sp = 18;

    union() {
        horn_mount(boss_d = 16);
        translate([0, 0, wall]) difference() {
            translate([-plate_l/2, -plate_w/2, 0]) cube([plate_l, plate_w, wall]);
            for (x = [-cam_hole_sp/2, cam_hole_sp/2], y = [-cam_hole_sp/2, cam_hole_sp/2])
                translate([x, y, -1]) cylinder(d = screw_m2, h = wall + 2);
            cylinder(d = 8, h = wall + 2, center = true);
        }
    }
}

// ============================================================
// RENDER SELECTOR
// ============================================================
if (part == "base") base_plate();
else if (part == "yoke") pan_yoke();
else if (part == "tilt") tilt_bracket();
else {
    base_plate();
    translate([60, 0, 0]) pan_yoke();
    translate([110, 0, 0]) tilt_bracket();
}