SpHEAR/Octathingy_mount_pcb.scad

//
// Spherical Harmonics Ear Project (*SpHEAR)
//
// Octathingy, Second Order Ambisonics Microphone
//
// based on:
// "A second-order soundfield microphone with improved polar pattern shape"
// by Eric Benjamin, Audio Engineering Society Convention Paper 8728, 
// October 2012, San Francisco
//
// Copyright 2015-2016, Fernando Lopez-Lezcano, All Rights Reserved
// nando@ccrma.stanford.edu
//
//  This program is free software: you can redistribute it and/or modify
//  it under the terms of the GNU General Public License as published by
//  the Free Software Foundation, either version 3 of the License, or
//  (at your option) any later version.
//
//  This program is distributed in the hope that it will be useful,
//  but WITHOUT ANY WARRANTY; without even the implied warranty of
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//  GNU General Public License for more details.
//
//  You should have received a copy of the GNU General Public License
//  along with this program.  If not, see <http://www.gnu.org/licenses/>.
//  
// 3d Models released under the Creative Commons license as follows:
//   Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)
// http://creativecommons.org/licenses/by-nc-sa/4.0/

include <Octathingy_common.scad>;
include <CCRMA_logo.scad>;

////
//// overrides

// inner radius of mount stalk
mount_radius = 4.0;

////
//// default model parameters
////

// size of Zapnspark printed circuit board
// kicad length = 79.375
// measured length = 79.20 (2016.08.25)
pcb_length = 79.20;
// kicad width = 19.050
// measured width = 18.82 (2016.08.25)
pcb_width = 18.85;
// ultimaker spec thickness = 1.61
// measured thickness = 1.56 (w/ copper)
pcb_thickness = 1.58;

// tolerance to add to length and width of pcb
//
// measured 3d print width = 18.70 (with pcb_fit = 0.3)
// actual printed = 18.70 - 0.3 = 16.97
// total correction = 18.85 - 16.97 = 1.88
//
pcb_fit = 0.4;

// tolerance add to thickness of pcb
//
// printed with pcb_tfit = 0.15 -> 1.58 + 0.15 = 1.73 (ideal printed)
// measured print channel = 1.63 : 0.1 thinner (ultimaker 2 plus, 2016.08.24)
// measured pcb thickness = 1.58 (othermill)
//
pcb_tfit = 0.15;

// we leave part of the pcb exposed on the bottom of the body so that we
// can solder the wires that connect the microphone with the
// preamplifier, same at the top of the pcb to solder the wires
// to the capsules
pcb_low_exp = 12.0;
pcb_hi_exp = 8.0;

// lip fit for flares
lip_fit = 0.15;

// clearance from the bottom and top of pcb's to the start of the flare,
// this adds space for the protuding molex pins on which we solder
pcb_low_clear = 15.0;
pcb_hi_clear = 15.0;

// depth of slot into which the printed circuit board fits
pcb_slot_depth = 1.0;

// diameter of four conductor cable
cable_diam = 9.5;

// lip that mounts flares into main body box
mount_lip = 10.0;

// capsule array mount, height of flare and stalk
flare_height = 50;
stalk_height = 60;

// wall thickness
wall = 1.0;

// back and front clearance of pcb (components and leads)
pcb_front = 3.00;
pcb_back = 1.80;

// calculated minimum "radius" of microphone box
box_radius = pcb_front + (pcb_thickness + pcb_tfit) + pcb_back + 2 * wall;

// calculated main body corner radius
mount_corner = box_radius - pcb_width / 2 + pcb_slot_depth + 4.0;

// body parameters
render_screw_holes = true;
radial_pcb_offset = 17.0;
octa_pcb_mount_height = pcb_length - pcb_low_exp - pcb_hi_exp;
octa_pcb_radius = radial_pcb_offset + pcb_width/2 + 5 * wall;

// body to flares snap joint arm slot width
snap_joint_slot_w = 0.75;

// width and radius of snap joint hook that locks upper and lower flanges to body
snap_joint_hook_w = 5.0;
snap_joint_hook_r = 1.4;

// dimensions of 12 pin male bottom connector
//
// Amphenol T 3635 002
// 12 pin DIN male to cable, gold plated contacts
//
// inner diameter of connector core
conn_core_diam = 13.00 + 0.2;
// outer diameter of connector core sleeve
conn_core_o_diam = 17.00;
// inner diameter of connector core sleeve
conn_core_s_diam = 15.00;

// from top of connector to sleeve
conn_core_sleeve = 13.00;
// from top of connector to holes
conn_core_holes_h = 6.00;
// between holes
conn_core_holes_w = 9.20;
// hole diameter
conn_core_holes_d = 1.95 + 0.2;
// screw head diameter
conn_core_screw_d = 2.75 + 0.5;
// sleeve overlap
conn_core_overlap = 3.00;

// shock mount parameters
//

ring_sep = 30.0;
ring_height = 10.0;
rubber_band_angle = 40;
main_radius_inc = (ring_sep / 2) / tan(rubber_band_angle);

// gap between internal ring and microphone body
internal_ring_gap = 1.0;

// connector that joins the two internal rings
connector_w = 10.0;
connector_d = 2.0;

// wall thickness and height of shock mount rings
ring_wall = 4 * wall;
ring_ext_height = 6;

// gap between external ring and support arm
ring_arm_gap = 20;


// the main body that holds the phantom power interfaces

module one_pcb_slot (pcb_w, pcb_l, pcb_t, slot_d, front, back, test = false) {
    d = pcb_t + front + back;
    render() translate([-(pcb_w/2 + wall/2), -back, 0]) {
        // make cage with slots for pcb
        difference() {
            translate([-2 * wall, 0, 0]) {
                cube([pcb_w + 4 * wall, d, pcb_l]);
            }
            translate([slot_d, 0, 0]) {
                cube([pcb_w - 2 * slot_d, pcb_t + front + back, pcb_l]);
            }
            translate([0, back, 0]) {
                cube([pcb_w, pcb_t, pcb_l]);
            }
            // make top and bottom entry channels
            translate([slot_d, back + pcb_t/2, 0]) {
                rotate([0, 0, 45]) cylinder(r1 = pcb_t * 1.1, r2 = 0, h = 8.0, $fn = 4);
            }
            translate([pcb_w - slot_d, back + pcb_t/2, 0]) {
                rotate([0, 0, 45]) cylinder(r1 = pcb_t * 1.1, r2 = 0, h = 8.0, $fn = 4);
            }
            translate([slot_d, back + pcb_t/2, pcb_l - 8.0]) {
                rotate([0, 0, 45]) cylinder(r2 = pcb_t * 1.1, r1 = 0, h = 8.0, $fn = 4);
            }
            translate([pcb_w - slot_d, back + pcb_t/2, pcb_l - 8.0]) {
                rotate([0, 0, 45]) cylinder(r2 = pcb_t * 1.1, r1 = 0, h = 8.0, $fn = 4);
            }
        }
        // add spar in the back
        translate([-2 * wall, -back + wall, 0]) {
            cube([pcb_w + 4 * wall, wall, pcb_l]);
        }
    }
    // add capacitor if in test mode
    if (test) {
        cap_diam = 10.2;
        translate([0, cap_diam/2 + pcb_t, 0]) {
            cylinder(r = cap_diam/2, h = 20, $fn = facets);
        }
    }
}

module rounded_octagon(height, radius) {
    intersection() {
        cylinder(r = radius, h = height, $fn = 8);
        cylinder(r = radius - wall, h = height, $fn = facets);
    }
}

module rounded_octagon_wall(height, radius, wall) {
    difference() {
        rounded_octagon(height, radius);
        rounded_octagon(height, radius - wall);
    }
}

module octa_mount_body(height, radius, lower_lip, upper_lip, clear) {
    // rotate pcb assembly so it does not interfere with the screws
    offset_angle = -16;
    // rotate individual pcb's to better use the internal space of the body
    twist_angle = 16;
    difference() {
        union() {
            difference() {
                union() {
                    // main body
                    rounded_octagon_wall(height, radius, 2 * wall);
                    // slots for printed circuit boards
                    intersection() {
                        for (r = [0:360/8:360]) rotate([0, 0, r + offset_angle]) {
                            translate([radial_pcb_offset, 0, 0]) {
                                rotate([0, 0, 180 + twist_angle]) {
                                    one_pcb_slot(pcb_width + pcb_fit, height * 2/3, pcb_thickness + pcb_tfit, 
                                        pcb_slot_depth, pcb_front, pcb_back, false);
                                }
                            }
                        }
                        // clip outside
                        rounded_octagon(height, radius);
                    }
                }
                // upper lip for flare to microphone
                translate([0, 0, height - upper_lip]) {
                    rounded_octagon_wall(upper_lip, radius, wall + lip_fit);
                }
                // lower lip for flare to cable or connector
                translate([0, 0, 0]) {
                    rounded_octagon_wall(upper_lip, radius, wall + lip_fit);
                }
            }
            if (render_screw_holes) {
                // add backplates for upper lip screws
                for (r = [45, 135, 225, 315]) {
                    rotate([0, 0, r]) translate([-(radius - 3 * wall), -2.5, 0]) {
                        cube([2, 5, height]);
                    }
                }
            }
        }
        if (render_screw_holes) {
            // make eight holes in the the body for screws that hold both flares
            // (number 0 size, 1/4" long = thread diameter: 1.6mm, head diameter: 2.75)
            difference() {
                for (z = [lower_lip/2, height - upper_lip/2]) {
                    for (r = [45, 135, 225, 315]) {
                        rotate([0, 0, r]) translate([-(radius + 2 * wall), 0, z]) {
                            rotate([0, 90, 0]) {
                                cylinder(r = 0.7, h = radius + wall, $fn = facets);
                            }
                        }
                    }
                }
                cylinder(r = radius/2, h = height);
            }
        }
    }
}

// flare from the body to the microphone stalk

module octa_mount_flare_no_ws(height, lip, transition, radius, top_radius, stalk_height, dot) {
    // bottom box
    difference() {
        union() {
            rounded_octagon_wall(height, radius, 2 * wall);
            if (render_screw_holes) {
                // small pedestals for the screws that attach the flare to the body
                // (number 0 size, 1/4" long = thread diameter: 1.6mm, head diameter: 2.75)
                for (r = [45, 135, 225, 315]) rotate([0, 0, r]) {
                    translate([radius - wall - 1.75, 0, lip/2]) {
                        rotate([0, 90, 0]) {
                            cylinder(r = 1.5, h = 2 * wall, $fn = facets);
                        }
                    }
                }
            }
        }
        // flange to mount on body
        rounded_octagon_wall(lip + 1.00, radius - wall, wall);
        // and make a smooth transition to avoid overhangs
        translate([0, 0, lip + 1.00]) {
            hull() {
                rounded_octagon_wall(thin_mint, radius - wall, wall);
                translate([0, 0, 1.0]) {
                    rounded_octagon_wall(thin_mint, radius - 2 * wall, wall);
                }
            }
        }
        if (render_screw_holes) {
            // holes for screws that attach the flare to the body
            // Number 0 Size, 1/4" Long = thread diameter: 1.6mm, head diameter: 2.75
            for (r = [45, 135, 225, 315]) rotate([0, 0, r]) {
                translate([radius/2, 0, lip/2]) {
                    rotate([0, 90, 0]) {
                        cylinder(r = (1.6 + 0.1)/2, h = radius, $fn = facets);
                    }
                }
            }
        }
    }
    // flare to round section
    translate([0, 0, height]) {
        difference() {
            hull() {
                rounded_octagon(thin_mint, radius);
                translate([0, 0, transition]) {
                    cylinder(r = top_radius, h = thin_mint, $fn = facets);
                }
            }
            hull() {
                rounded_octagon(thin_mint, radius - wall);
                translate([0, 0, transition]) {
                    cylinder(r = top_radius - wall, h = thin_mint, $fn = facets);
                }
            }
        }
    }
    // cylindrical stalk
    translate([0, 0, height + transition]) {
        difference() {
            cylinder(r = top_radius, h = stalk_height, $fn = facets);
            cylinder(r = top_radius - wall, h = stalk_height, $fn = facets);
        }
        // add marker for "back of microphone" orientation
        if (dot == 1) {
            rotate([0, 0, 90]) {
                translate([0, top_radius - wall * 2 / 3, stalk_height - top_radius]) {
                    difference() {
                        sphere(r = top_radius / 3, $fn = 32);
                        translate([0, -top_radius + top_radius / 2, 0]) {
                            cube([top_radius, top_radius, top_radius], center = true);
                        }
                    }
                }
            }
        }
        // close stalk and add holes for cables
        translate([0, 0, stalk_height - top_radius - wall]) {
            difference() {
                cylinder(r = top_radius - wall, h = top_radius + wall, $fn = facets);
                translate([0, 0, 0]) {
                    sphere(r = top_radius - wall, $fn = facets);
                }
                wire_diam = mic_wire_diam + mic_wire_fit;
                for (r = [0, 90, 180, 270]) rotate([0, 0, r]) {
                    for (t = [0, 1]) {
                        rotate([0, 0, 45 * t]) translate([top_radius - wire_diam - t * wire_diam * 2/3, 0, wall]) {
                            cylinder(r = wire_diam / 2, h = top_radius * 2, $fn = facets);
                        }
                    }
                }
                translate([0, 0, wall]) cylinder(r = wire_diam, h = top_radius * 2, $fn = facets);
            }
        }
    }
}

module octa_mount_flare(height, lip, transition, radius, top_radius, stalk_height, dot) {
    // transition from bottom box to windscreen mounting thread
    transition_to_threads = 5;
    // bottom box
    difference() {
        union() {
            rounded_octagon_wall(height, radius, 2 * wall);
            if (render_screw_holes) {
                // small pedestals for the screws that attach the flare to the body
                // (number 0 size, 1/4" long = thread diameter: 1.6mm, head diameter: 2.75)
                for (r = [45, 135, 225, 315]) rotate([0, 0, r]) {
                    translate([radius - wall - 1.75, 0, lip/2]) {
                        rotate([0, 90, 0]) {
                            cylinder(r = 1.5, h = 2 * wall, $fn = facets);
                        }
                    }
                }
            }
            // indicator of "front" of microphone
            rotate([0, 0, 180]) translate([radius - 0.75, 0, 0]) {
                cylinder(r = 1.0, h = lip/2, $fn = facets);
            }
        }
        // flange to mount on body
        rounded_octagon_wall(lip + 1.00, radius - wall, wall);
        // and make a smooth transition to avoid overhangs
        translate([0, 0, lip + 1.00]) {
            hull() {
                rounded_octagon_wall(thin_mint, radius - wall, wall);
                translate([0, 0, 1.0]) {
                    rounded_octagon_wall(thin_mint, radius - 2 * wall, wall);
                }
            }
        }
        if (render_screw_holes) {
            // holes for screws that attach the flare to the body
            // Number 0 Size, 1/4" Long = thread diameter: 1.6mm, head diameter: 2.75
            for (r = [45, 135, 225, 315]) rotate([0, 0, r]) {
                translate([radius/2, 0, lip/2]) {
                    rotate([0, 90, 0]) {
                        cylinder(r = (1.6 + 0.1)/2, h = radius, $fn = facets);
                    }
                }
            }
        }
    }
    // flare to windscreen threads
    translate([0, 0, height - windscreen_thread_height - transition_to_threads]) {
        difference() {
            hull() {
                rounded_octagon(thin_mint, radius);
                translate([0, 0, transition_to_threads]) {
                    cylinder(r = windscreen_thread_radius + 0.5, h = thin_mint, $fn = facets);
                }
            }
            hull() {
                rounded_octagon(thin_mint, radius - wall);
                translate([0, 0, transition_to_threads]) {
                    cylinder(r = windscreen_thread_radius - windscreen_thread_depth - wall, h = thin_mint, $fn = facets);
                }
            }
        }
    }
    // windscreen mounting threads
    translate([0, 0, height - windscreen_thread_height]) difference() {
        metric_thread(diameter = windscreen_thread_radius * 2, pitch = windscreen_thread_pitch,
            length = windscreen_thread_height, angle = windscreen_thread_angle, internal = false);
        cylinder(r = windscreen_thread_radius - wall - windscreen_thread_depth, h = windscreen_thread_height + thin_mint, $fn = facets);
    }

    // flare to stalk
    translate([0, 0, height - 1.5]) {
        difference() {
            hull() {
                cylinder(r = windscreen_thread_radius - windscreen_thread_depth, h = thin_mint, $fn = facets);
                translate([0, 0, transition + 1.5]) {
                    cylinder(r = top_radius, h = thin_mint, $fn = facets);
                }
            }
            hull() {
                cylinder(r = windscreen_thread_radius - windscreen_thread_depth - wall, h = thin_mint, $fn = facets);
                translate([0, 0, transition + 1.5]) {
                    cylinder(r = top_radius - wall, h = thin_mint, $fn = facets);
                }
            }
        }
    }
    // cylindrical stalk
    translate([0, 0, height + transition]) {
        difference() {
            cylinder(r = top_radius, h = stalk_height, $fn = facets);
            cylinder(r = top_radius - wall, h = stalk_height, $fn = facets);
        }
        // close stalk and add holes for cables
        translate([0, 0, stalk_height - top_radius - wall]) {
            difference() {
                cylinder(r = top_radius - wall, h = top_radius + wall, $fn = facets);
                translate([0, 0, 0]) {
                    sphere(r = top_radius - wall, $fn = facets);
                }
                wire_diam = mic_wire_diam + mic_wire_fit;
                for (r = [0, 90, 180, 270]) rotate([0, 0, r]) {
                    for (t = [0, 1]) {
                        rotate([0, 0, 45 * t]) translate([top_radius - wire_diam - t * wire_diam * 2/3, 0, wall]) {
                            cylinder(r = wire_diam / 2, h = top_radius * 2, $fn = facets);
                        }
                    }
                }
                translate([0, 0, wall]) cylinder(r = wire_diam, h = top_radius * 2, $fn = facets);
            }
        }
    }
}

// flares from the body to a dual cable housing

module octa_mount_flare_dual(height, lip, transition, xradius, yradius, corner, top_radius, stalk_height) {
    // hack to get it to render, fix problem in rounded_block when radius is equal to corner...
    delta = 0.001;
    difference() {
        union() {
            // bottom rounded box
            difference() {
                rounded_block(height, xradius, yradius, corner);
                rounded_block_relative(height, xradius, yradius, corner, -(2 * wall));
                // flange to mount on body
                rounded_block_relative(lip + 1.00, xradius, yradius, corner, - (wall));
                // and make a smooth transition to avoid overhangs
                translate([0, 0, lip + 1.00]) {
                    hull() {
                        rounded_block_relative(thin_mint, xradius, yradius, corner, - wall);
                        translate([0, 0, 1.0]) {
                            rounded_block_relative(thin_mint, xradius, yradius, corner, - 2 * wall);
                        }
                    }
                }
            }
            // flare to rounded section
            translate([0, 0, height]) {
                difference() {
                    hull() {
                        rounded_block(thin_mint, xradius, yradius, corner);
                        translate([0, 0, transition]) {
                            rounded_block(thin_mint, top_radius + wall / 2, top_radius * 2 + wall / 2, top_radius - delta);
                        }
                    }
                    hull() {
                        rounded_block_relative(thin_mint, xradius, yradius, corner, - 2 * wall);
                        translate([0, -top_radius, transition]) {
                            cube([thin_mint, (top_radius) * 2, thin_mint]);
                        }
                    }
                }
            }
            // corner box cable stalk
            translate([0, 0, height + transition]) {
                rounded_block(stalk_height, top_radius + wall  / 2, top_radius * 2 + wall / 2, top_radius - delta);
            }
        }
        // holes for the cables
        for (offset = [top_radius - wall/2, -(top_radius - wall/2)]) {
            translate([0, offset, 0]){
                cylinder(r = top_radius - wall, h = height + transition + stalk_height, $fn = facets);
            }
        }
    }
}

// flare from the body to a dual conector housing

// bottom connector holder

module tetra_mount_connector_holder(height, radius, inside_radius, sleeve_height, sleeve_radius) {
    difference() {
        union() {
            cylinder(r = radius, h = height, $fn = facets);
            // add seats for screw heads
            for (m = [-1, 1]) translate([m * conn_core_holes_w / 2, radius / 2, conn_core_holes_h]) {
                rotate([90, 0, 0]) {
                    scale([1, 1, 1]) cylinder(r = conn_core_screw_d / 2, h = radius * 1.43, $fn = facets);
                }
            }
        }
        cylinder(r = inside_radius, h = height, $fn = facets);
        // transition from thin wall to thick wall at the bottom of connector
        *cylinder(r1 = radius - wall, r2 = inside_radius, h = 2.0, $fn = facets);
        // holes for connector core screws
        for (m = [-1, 1]) translate([m * conn_core_holes_w / 2, - radius / 3, conn_core_holes_h]) {
            rotate([90, 0, 0]) {
                cylinder(r = conn_core_holes_d / 2, h = radius, $fn = facets);
            }
        }
        // substract cutout for screw heads
        for (m = [-1, 1]) translate([m * conn_core_holes_w / 2, - radius + 1.5, conn_core_holes_h]) {
            rotate([90, 0, 0]) {
                cylinder(r = conn_core_screw_d / 2, h = 2.0, $fn = facets);
            }
        }
    }
    // thinner cylinder sits inside connector sleeve
    translate([0, 0, height]) {
        difference() {
            cylinder(r = sleeve_radius, h = sleeve_height, $fn = facets);
            cylinder(r = inside_radius, h = sleeve_height, $fn = facets);
        }
    }
}

// flare to dual cable connectors

module octa_mount_flare_connector(height, lip, transition, radius, top_xradius, top_yradius) {
    // hack to get it to render, fix problem in rounded_block when radius is equal to corner...
    delta = 0.001;
    // bottom rounded box
    difference() {
        union() {
            rounded_octagon_wall(height, radius, 2 * wall);
            if (render_screw_holes) {
                // small pedestals for the screws that attach the flare to the body
                // (number 0 size, 1/4" long = thread diameter: 1.6mm, head diameter: 2.75)
                for (r = [45, 135, 225, 315]) rotate([0, 0, r]) {
                    translate([radius - wall - 1.75, 0, lip/2]) {
                        rotate([0, 90, 0]) {
                            cylinder(r = 1.5, h = 2 * wall, $fn = facets);
                        }
                    }
                }
            }
        }
        // flange to mount on body
        rounded_octagon_wall(lip + 1.00, radius - wall, wall);
        // and make a smooth transition to avoid overhangs
        translate([0, 0, lip + 1.00]) {
            hull() {
                rounded_octagon_wall(thin_mint, radius - wall, wall);
                translate([0, 0, 1.0]) {
                    rounded_octagon_wall(thin_mint, radius - 2 * wall, wall);
                }
            }
        }
        if (render_screw_holes) {
            // holes for screws that attach the flare to the body
            // Number 0 Size, 1/4" Long = thread diameter: 1.6mm, head diameter: 2.75
            for (r = [45, 135, 225, 315]) rotate([0, 0, r]) {
                translate([radius/2, 0, lip/2]) {
                    rotate([0, 90, 0]) {
                        cylinder(r = (1.6 + 0.1)/2, h = radius, $fn = facets);
                    }
                }
            }
        }
    }
    // flare to rounded section
    translate([0, 0, height]) {
        difference() {
            hull() {
                rounded_octagon(thin_mint, radius);
                translate([0, 0, transition]) {
                    rounded_block(thin_mint, top_xradius, top_yradius, top_xradius - delta);
                }
            }
            hull() {
                rounded_octagon(thin_mint, radius - 2 * wall);
                translate([0, -top_xradius, transition]) {
                    cube([thin_mint, (top_xradius) * 2, thin_mint]);
                }
            }
        }
    }
}

// top conical section that plugs into capsule array

module octa_capsule_array_mount(angles) {
    difference() {
        union() {
            difference() {
                cylinder(h = mount_top_height, r1 = mount_radius + wall, r2 = mount_radius_capsule, $fn = facets);
                cylinder(h = mount_top_height, r1 = mount_radius, r2 = mount_radius_capsule - 3 * wall * wall, $fn = facets);
            }
            // second set of optional "leaves" to get a better mount
            *difference() {
                cylinder(h = mount_top_height, r1 = mount_radius + wall, r2 = mount_radius_capsule * 0.8, $fn = facets);
                cylinder(h = mount_top_height, r1 = mount_radius, r2 = mount_radius_capsule * 0.8 - 1.2 * wall, $fn = facets);
            }
        }
        // indentations that match the four lower capsule holders
        // add ridge height adjustment
        translate([0, 0, mount_top_height + (mic_radius - capsule_height) + capsule_height * cos(90 - elev_angle) - 2]) {
            for (az = angles) {
                rotate([0, 180 - elev_angle, az + 45]) {
                    translate([0, 0, mic_radius - capsule_height]) {
                        capsule(leg_angles, 0, 1, ridge_wfit, ridge_hfit, 1);
                    }
                }
            }
        }
        // indentations at the top to open up the array a bit
        translate([0, 0, mount_top_height + mount_radius_capsule / 8]) {
            for (rot = [45, 135, -135, -45]) {
                translate([0, 0, 0]) {
                    rotate([0, 90, rot]) {
                        linear_extrude(height = mount_radius_capsule) {
                            minkowski() {
                                polygon(points = [[0, mount_radius_capsule * 0.35], [0, - mount_radius_capsule * 0.35], 
                                                  [mount_radius_capsule * 2 / 3, 0]]);
                                circle(r = 1.0, $fn = facets);
                            }
                        }
                    }
                }
            }
        }
    }
}

////
//// render all the different parts
////

// microphone body: flare to capsule array (slips into PCB holder body)
//
module render_octa_capsule_flare(z_offset) {
    translate([0, 0, z_offset]) {
        octa_mount_flare(pcb_hi_clear + pcb_hi_exp, mount_lip, flare_height, octa_pcb_radius, mount_radius + wall, stalk_height, 1);
        translate([0, 0, pcb_hi_clear + pcb_hi_exp + flare_height + stalk_height]) {
            octa_capsule_array_mount([45, 135, -45, -135]);
        }
    }
}

// microphone body: main body, holds printed circuit boards
//

module render_octa_pcb_mount(z_offset, showint) {
    translate([0, 0, z_offset]) {
        octa_mount_body(octa_pcb_mount_height, octa_pcb_radius, mount_lip, mount_lip, 0);
        // add ccrma logo
        rotate([0, 0, -90 + 22.5]) {
            translate([0, -(octa_pcb_radius - 3.75), octa_pcb_mount_height / 2]) {
                rotate([90, 270, 0]) {
                    logo_scale = 1 / 2.4;
                    scale([logo_scale, logo_scale, 1.0]) {
                        ccrma_logo(1.65);
                    }
                }
            }
        }
    }
}

// microphone body: flare to microphone cable (slips into PCB holder body)
//
module render_octa_cable_flare(z_offset, flip) {
    translate([0, 0, z_offset]) {
        octa_mount_flare_dual(pcb_low_clear + pcb_low_exp, mount_lip, 20, box_radius + wall, box_radius * 2 - wall, 
                              mount_corner, cable_diam / 2 + wall, 10, 0);
    }
}

// microphone body: flare to dual cable connectors (slips into PCB holder body)
//
module render_octa_connector_flare(z_offset, flip) {
    conn_offset = 2.0;
    conn_wall = conn_core_o_diam / 2 - conn_core_diam / 2;
    translate([0, 0, z_offset]) {
        difference() {
            union() {
                octa_mount_flare_connector(pcb_low_clear + pcb_low_exp, mount_lip, 20,
                            octa_pcb_radius,
                            conn_core_o_diam / 2, conn_core_o_diam + conn_offset);
                for (m = [0, 1]) mirror([0, m, 0]) translate([0, conn_core_o_diam / 2 + conn_offset, pcb_low_clear + pcb_low_exp + 20]) {
                    // add two connectors
                    rotate([0, 0, -90]) {
                        tetra_mount_connector_holder(conn_core_sleeve, conn_core_o_diam / 2, conn_core_diam / 2,
                            conn_core_overlap, conn_core_s_diam / 2);
                    }
                    // add wall in between the two connectors
                    translate([- 2 * wall, - (conn_core_o_diam / 2 + conn_offset), 0]) {
                        cube([4 * wall, conn_offset + wall, 10]);
                    }
                }
            }
            // redo the hole in the connector holder so that it drills into the top of the flare
            for (m = [0, 1]) mirror([0, m, 0]) translate([0, conn_core_o_diam / 2 + conn_offset, 0]) {
                cylinder(r = conn_core_diam / 2, h = 100, $fn = facets);
            }
        }
    }
}

// microphone body: render all parts with a vertical separation
//
module render_octa_body(z_offset, spread, showint) {
    rotate([0, 180, 0]) {
        render_octa_connector_flare(0);
    }
    lippy = spread - mount_lip;
    render_octa_pcb_mount(lippy, showint);
    render_octa_capsule_flare(octa_pcb_mount_height + 2 * lippy);
}

// microphone: render the full assembly with vertical separation between components
//
module render_octa_microphone(z_offset, spread) {
    render_octa_body(z_offset, spread);
    lippy = spread - mount_lip;
    render_octa_capsule_array(z_offset + octa_pcb_mount_height + mount_top_height +
            flare_height + stalk_height + pcb_hi_clear + pcb_hi_exp + 2 * lippy + spread + mic_radius);
}

// microphone: render the full assembly with vertical separation between components
//             cut out half of the assembly so that we can see the inside
//

module render_octa_microphone_cutout(z_offset, spread) {
    difference() {
        render_octa_microphone(z_offset, spread);
        // a cube that blots out 1/4 of the microphone
        rotate([0, 0, 90]) {
            translate([0, 0, -50]) {
                cube([50, 100, 650]);
            }
        }
    }
}

// shock mount: microphone clip on stand mount
//

module render_octa_shock_mount_stand(z_offset) {
    translate([z_offset]) {
        shock_mount_stand(mic_mount_height, mount_wall, mic_mount_wall);
    }
}

// shock mount: external ring
//

module render_octa_shock_mount_external_ring(z_offset) {
    translate([0, 0, z_offset]) {
        shock_mount_external_ring(ring_height, box_radius + wall, box_radius * 2 - wall, mount_corner, main_radius_inc, 0);
    }
}

// shock mount: bottom internal ring
//

module render_octa_shock_mount_internal_ring_bot(z_offset) {
    translate([0, 0, z_offset]) {
        shock_mount_internal_ring(ring_height, box_radius + wall, box_radius * 2 - wall, mount_corner, internal_ring_gap, 1);
    }
}

// shock mount: top internal ring
//

module render_octa_shock_mount_internal_ring_top(z_offset) {
    translate([0, 0, z_offset]) {
        shock_mount_internal_ring(ring_height, box_radius + wall, box_radius * 2 - wall, mount_corner, internal_ring_gap, 0);
    }
}

// shock mount: all four internal ring connectors
//

module render_octa_shock_mount_ring_connectors(offset) {
    for (o = [0, 1, 2, 3]) {
        translate([-18, (10 + offset) * o, 0]) {
            shock_mount_connector(ring_sep, 4, connector_w, connector_d, 0.1);
        }
    }
}

// shock mount: render all parts
//

module render_octa_shock_mount(z_offset) {
    // internal rings
    translate([0, 0, z_offset + ring_sep / 2]) {
        render_octa_shock_mount_internal_ring_top(0);
        rotate([0, 180, 0]) {
            render_octa_shock_mount_internal_ring_bot(ring_sep + 2);
        }
        // insert the connecting rods
        for (r = [0, 90, 180, 270]) {
            rotate([0, 0, r]) {
                translate([((r % 180) ? box_radius * 2 : box_radius) + 3 * wall + internal_ring_gap, 0, -1]) {
                    rotate([0, 90, 0]) {
                        translate([-4, -5, 1]) {
                            shock_mount_connector(ring_sep, 4, connector_w, connector_d, 0.1);
                        }
                    }
                }
            }
        }
    }
    // external ring
    translate([0, 0, z_offset - ring_height / 4]) {
        render_octa_shock_mount_external_ring(0);
    }
    // mount to stand
    translate([box_radius + mount_corner + ring_wall + ring_arm_gap + 8 + ring_wall / 2 + 4, 0, -(mic_mount_height + mic_mount_radius + ring_height / 4)]) {
        render_octa_shock_mount_stand(0);
    }
}