/*
  Copyright (C) 2015 Daniel Watson
  See the end of the file for license conditions.
*/
// challenge-bot
// GNU AGPLv3 (or later at your option)
// project available here:
// https://challenge-bot.com/

/*
  this holds an hc-sr04 sonar sensor to a 3/16 inch deck.
  http://fritzing.org/projects/hc-sr04-project
  it can hold the sonar sensor either facing down, or forwards.
  when facing down, it can detect if it passes over the edge of a table.
  when facing forwards, it can detect and follow something in front of it.
 */

$fn = 60;

// 3/16 inch in mm deck_depth = 4.7625;
// 1/4 inch in mm = 6.35
// subtract a little to be a squeeze fit
deck_depth = 4.7625 - 0.4;
// sonar sensor measurements taken with calipers:
//  10.82 in between, 42.33 outside, 15.82 diameter
// measured diameter of 15.82 with calipers,
//  but when printed ends up being too small, so add some
sonar_diameter = 15.82 + 0.4;
sonar_radius = sonar_diameter / 2;
sonar_height = 13.8;
between_sonar_centers = sonar_diameter + 10.82;
// the sonar cylinders are placed on the pcb at slightly different positions
//  from one sensor to the next, so this allows for that variance.
between_sonar_centers_variance = 2;
// keep at least this much plastic surrounding the sonar cylinder on all sides
buffer = 3;
binder_clip_attacher_length = 30; // not measured; just a rough estimate
screw_hole = 2.2;
sonar_holder_length = buffer + between_sonar_centers + sonar_diameter + buffer + binder_clip_attacher_length;
sonar_holder_width = buffer + sonar_diameter + buffer;
// sonar_holder_depth is deck_depth minus a little bit to make arm fit
//  into deck holder
sonar_holder_depth = deck_depth - 0.7875;

deck_holder_length = sonar_holder_depth * 2 + deck_depth + 15;
module sonar_holder_2d() {
  difference() {
    square([sonar_holder_length, sonar_holder_width]); } }

module sonars() {
  translate([between_sonar_centers / 2, 0, 0]) {
    cylinder(r = sonar_radius, h = sonar_height); }
  // for the variance with which the physical sonar cylinders are placed
  translate([between_sonar_centers / 2 - between_sonar_centers_variance, 0, 0]) {
    cylinder(r = sonar_radius, h = sonar_height);
    translate([0, -sonar_radius, 0]) {
      cube([between_sonar_centers_variance, sonar_diameter, sonar_height]); } }
  translate([-between_sonar_centers / 2, 0, 0]) {
    cylinder(r = sonar_radius, h = sonar_height); } }

module sonar_holder() {
    difference() {
      difference() {
	cube([sonar_holder_length, sonar_holder_width, sonar_holder_depth]);
	translate([sonar_holder_length - between_sonar_centers, sonar_holder_width / 2, -0.05]) {
	  sonars(); } }
      translate([binder_clip_attacher_length / 2, sonar_holder_width / 2], 0) {
      cylinder(r =  screw_hole, h = sonar_holder_depth); } } }

module attaching_piece() {
  linear_extrude(height = sonar_holder_depth) {
    difference() {
      square(sonar_holder_width, center = true);
      circle(screw_hole); } } }

/*
  This file is part of challenge-bot.

  Challenge-bot is free software: you can redistribute it and/or modify
  it under the terms of the GNU Affero General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  (at your option) any later version.

  GNU Affero Emacs 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 Affero General Public License for more details.

  You should have received a copy of the GNU Affero General Public License
  along with challenge-bot.  If not, see <http://www.gnu.org/licenses/>.
*/