$fn=64;
baseplate_hole_distance = 56;

battery_x = 105;
battery_y = 35;
battery_z = 25;

frame_x = 10;
frame_y = 62;
frame_z = 3;

module cube_centered(x,y,z) {
    translate([-x/2, -y/2, 0]) cube([x, y, z]);
}

module cube_round_corners(x,y,z) {
    hull() {
        translate([-x/2, -y/2, 0]) cylinder(r=3, h=z);
        translate([ x/2, -y/2, 0]) cylinder(r=3, h=z);        
        translate([-x/2,  y/2, 0]) cylinder(r=3, h=z);
        translate([ x/2,  y/2, 0]) cylinder(r=3, h=z);        
    }
}

difference() {
    union() {
        cube_round_corners(frame_x, frame_y, frame_z);
        cube_round_corners(frame_x, battery_y, battery_z + 3);
    }
    cube_centered(battery_x, battery_y, battery_z);
    translate([0, -baseplate_hole_distance/2, 0]) cylinder(d=3, h=3);
    translate([0,  baseplate_hole_distance/2, 0]) cylinder(d=3, h=3);
}