// CieloTrack receiver enclosure — a stacked pair of Seeed XIAO ESP32-S3 boards,
// outdoors, with the antenna on an SMA bulkhead.
//
// EVERY DIMENSION BELOW IS A DEFAULT, NOT A MEASUREMENT.
// The one that matters most is stack_h: the soldered header pins and the JST housing
// dominate the internal height, and nobody has measured this build. Measure the real
// stack with calipers and set it before printing anything.
//
//   openscad -D part=\"base\" -o base.stl cielotrack-case.scad
//   openscad -D part=\"lid\"  -o lid.stl  cielotrack-case.scad
//
// Print in PETG or ASA. Not PLA: an enclosed box in Texas sun passes PLA's softening
// point and sags. Never carbon-filled filament — it is conductive and will detune or
// shield the antenna, and the board will look healthy while hearing less.

/* [What to measure] */
board_l      = 21.0;   // XIAO ESP32-S3, published. Verify.
board_w      = 17.5;   // ditto
stack_h      = 16.0;   // MEASURE THIS: two boards, header pins, JST housing
pigtail_slack= 18.0;   // room for the u.FL lead to loop without a tight bend

/* [Fit] */
clearance    = 1.2;    // around the stack, per side
wall         = 2.4;    // 3 perimeters at 0.4mm nozzle; weatherproof rather than minimal
floor_t      = 2.4;
lid_t        = 2.4;
lip_h        = 3.0;    // lid skirt depth
lip_gap      = 0.25;   // printed fit; loosen to 0.35 if your printer runs tight

/* [Openings] */
sma_d        = 6.6;    // SMA bulkhead nut, typical 6.5mm — check yours
// The bulkhead sits on an angled boss rather than square to the wall. Signal from this
// site peaks around 30-40 degrees of elevation and falls off both sides, so an antenna
// forced vertical is pointed above where the aircraft actually are. Most rubber-duck
// antennas hinge at the base, so this only has to get the mount into the right range and
// let the hinge do the rest.
//
// Read as "do not force vertical", not as a measured optimum: 330 rows over six bins,
// and RSSI mixes distance with angle, since a closer aircraft is both louder and higher.
sma_tilt     = 35;     // degrees up from horizontal
boss_d       = 13.0;   // flat pad for the bulkhead nut to seat against
boss_h       = 4.5;
// One opening, not two. The boards are stacked, so their USB-C connectors sit one above
// the other at the same end — separated in Z by the stack pitch, not side by side. A
// single slot spanning both cannot misalign with either, and two 10mm ports side by side
// did not fit the 28mm end face anyway.
usb_w        = 11.0;   // USB-C plug body plus a cable boot
usb_slot_h   = 13.0;   // MEASURE: centre of lower connector to centre of upper, plus ~7
vent_d       = 3.0;
drain_d      = 4.0;

/* [Mounting] */
ear_t        = 3.0;
ear_r        = 7.0;
screw_d      = 4.4;    // M4 clearance

/* [Render] */
part = "both";         // "base" | "lid" | "both"
$fn = 64;

// ---- derived ------------------------------------------------------------------
inner_l = board_l + 2*clearance;
inner_w = board_w + 2*clearance + pigtail_slack;
inner_h = stack_h + 2;                       // 2mm headroom over the stack
outer_l = inner_l + 2*wall;
outer_w = inner_w + 2*wall;
outer_h = inner_h + floor_t;

module rrect(l, w, h, r=2.5) {
    hull() for (x=[r-l/2, l/2-r], y=[r-w/2, w/2-r]) translate([x,y,0]) cylinder(r=r, h=h);
}

module base() {
    difference() {
        union() {
            rrect(outer_l, outer_w, outer_h);
            // mounting ears, outside the sealed volume so no screw enters the box
            for (s=[-1,1]) translate([s*(outer_l/2 + ear_r - 1.5), 0, 0])
                cylinder(r=ear_r, h=ear_t);
            // Angled boss: gives the bulkhead nut a flat face to seat against at the
            // tilt, instead of biting into a curved or sloping wall.
            translate([0, outer_w/2 - 1, floor_t + inner_h/2])
                rotate([90 - sma_tilt, 0, 0]) cylinder(d=boss_d, h=boss_h*2, center=true);
        }
        // cavity
        translate([0,0,floor_t]) rrect(inner_l, inner_w, inner_h + 1, r=2.0);

        // SMA bore through the angled boss. Tilted up, never straight up: a hole in a
        // horizontal face is where water gets in, and it is also the orientation the
        // signal data argues against.
        translate([0, outer_w/2 - 1, floor_t + inner_h/2])
            rotate([90 - sma_tilt, 0, 0]) cylinder(d=sma_d, h=40, center=true);

        // One tall slot reaching both connectors. They are flashed one at a time and,
        // with UUSB tied between the boards, must never both be plugged in at once — so
        // a single opening is a feature, not a compromise.
        translate([0, -outer_w/2, floor_t + usb_slot_h/2 + 1.5])
            cube([usb_w, wall*3, usb_slot_h], center=true);

        // vents low on both long sides; nothing open facing up
        for (s=[-1,1]) for (i=[-1,0,1])
            translate([s*outer_l/2, i*7, floor_t + 3])
                rotate([0,90,0]) cylinder(d=vent_d, h=wall*3, center=true);

        // drain at the lowest point
        translate([0,0,-1]) cylinder(d=drain_d, h=floor_t+2);

        // mounting holes
        for (s=[-1,1]) translate([s*(outer_l/2 + ear_r - 1.5), 0, -1])
            cylinder(d=screw_d, h=ear_t+2);
    }
}

module lid() {
    difference() {
        union() {
            rrect(outer_l, outer_w, lid_t);
            // skirt that drops into the cavity
            translate([0,0,-lip_h])
                rrect(inner_l - lip_gap*2, inner_w - lip_gap*2, lip_h, r=2.0);
        }
        // hollow the skirt so it is a lip, not a plug
        translate([0,0,-lip_h-0.5])
            rrect(inner_l - lip_gap*2 - 2*1.6, inner_w - lip_gap*2 - 2*1.6, lip_h+1, r=1.2);
    }
}

if (part == "base") base();
else if (part == "lid") lid();
else { base(); translate([0, outer_w + 6, 0]) lid(); }