My First 3D Design -- tray for tiny oscilloscope

oscillo-tray.scad

// $fn = 24;  // uncomment for production

// set to true for production -- this prevents hex render which takes
// a couple minutes
use_hex_base = false;  


module tab(ringw=6.5, stemh=20, stemw=8, thick=3) {
    cube([stemw, thick, stemh]);
    translate([stemw / 2, 0, stemh + ringw]){
       rotate(270,v=[1,0,0]) {
         rotate_extrude() {
           translate([ringw, 0, 0])
           square([thick + 1,thick]);
         };
       };
    };
};

module hex(x,y, render=true)
{
    if (!render) {
        difference()
        {
            translate([x,y,-height2/20]) 
                cylinder(r=(hex_radius+hex_border_width/20), h=height2/10, $fn=6);	
            translate([x,y,-height2/20]) 
                cylinder(r=(hex_radius-hex_border_width/20), h=height2/10, $fn=6);
        }
    }
}

module tray(x,y,z,wt,open_face=false) {
    difference() {
        // basic cuboid shape
        cube([x, y, z]);

        // cut out the space from the basic cuboid shape
        // to make the tray
        translate([wt,wt,0]) { 
            cube([x - wt * 2, y - wt * 2, z]);
        }
        
        if (open_face) {
            difference() {
                translate([0, 0, z / 4]) {                
                    // cut out part of the front face to reduce material
                    cube([x, y - wt, z / 2]);
                };

                // rigidity supports are useful to keep the shape if 
                // content is a little weighty
                translate([0,0,0]) cube([wt, wt, z]);
                translate([x-wt, 0, 0]) cube([wt, wt, z]);
            }
        };
    }
};

module tabs_for_tray(x, y, z, sep, tabdepth, tabheight=10) {
    tab1 = (x - sep) / 2;

    translate([tab1, y -tabdepth, z]) {
        tab(stemh = tabheight, thick = tabdepth);
    };  
    
    translate([tab_separation, y-tabdepth, z]) {
        tab(stemh = tabheight, thick = tabdepth);
    };
}

length = 100;
depth = 40;
height = 35;
wall_thickness = 3;


tray(length, depth, height, wall_thickness, true);

tab_separation = 80;

tabs_for_tray(length, depth, height, tab_separation, wall_thickness);


// first arg is vector that defines the bounding box, length, width, height
// second arg in the 'diameter' of the holes. In OpenScad, this refers to the corner-to-corner diameter, not flat-to-flat
// this diameter is 2/sqrt(3) times larger than flat to flat
// third arg is wall thickness.  This also is measured that the corners, not the flats. 

//hexgrid([length, depth, 2], 10, 5);


// Customizable hex pattern
// Created by Kjell Kernen
// Date 22.9.2014

/*[Pattern Parameters]*/
// of the pattern in mm:
width=100;       // [10:100]

// of the pattern in mm:
lenght=40;      // [10:100]

// of the pattern in tens of mm:
height2=5;       // [2:200]

// in tens of mm:
border_width=20;// [2:100]

// in mm:
hex_radius=5;   // [1:20]

// in tens of mm: 
hex_border_width=30; // [2:50]

/*[Hidden]*/

if (use_hex_base) {
    xborder=(border_width/10<width)?width-border_width/10:0;
    yborder=(border_width/10<lenght)?lenght-border_width/10:0;

    x=sqrt(3/4*hex_radius*hex_radius);
    ystep=2*x;
    xstep=3*hex_radius/2;



    translate([50,20,0]){
        //Pattern
        intersection()
        {
            for (xi=[0:xstep:width])
                for(yi=[0:ystep:lenght])
                    hex(xi-width/2,((((xi/xstep)%2)==0)?0:ystep/2)+yi-lenght/2);
            translate([-width/2, -lenght/2, -height2/20]) 
                cube([width,lenght,height2/10]);
        }

        // Frame
        difference()
        {
            translate([-width/2, -lenght/2, -height2/20]) 
                cube([width,lenght,height2/10]);
            translate([-xborder/2, -yborder/2, -(height2/20+0.1)]) 
                cube([xborder,yborder,height2/10+0.2]); 
        }
    }
} else {
    translate([0,0,0]) #cube([length, depth, wall_thickness]);
}

Revision 6 contains an option to switch on the hex base or leave a solid base. Use the solid base for test renders and switch to hex for a nicer thing that takes longer to render (90 sec vs 0 sec eg). Tabs are not standing out from the body of the tray anymore, they are incorporated, and by default shorter too. Increased the wall thickness to 3mm. For more rigidity, have put supports in at the front corners of the open tray.