diff --git a/preproto_bottom.scad b/preproto_bottom.scad
new file mode 100644
index 0000000..9e8ebe1
--- /dev/null
+++ b/preproto_bottom.scad
@@ -0,0 +1,54 @@
+$fn = 64;
+
+radius = 7;
+inner_radius = 5;
+pcb_width = 150.7;
+pcb_height = 64.1;
+margin = 2;
+thickness = 4;
+
+key_width = 9;
+key_height = 6;
+key_padding = 1;
+key_margin = 1;
+
+difference() {
+  union() {
+    // base shape
+    hull() {
+      cylinder(h=thickness, r=radius);
+      translate([pcb_width+2*margin-2*radius,0,0]) cylinder(h=thickness, r=radius);
+      translate([0,pcb_height+2*margin-2*radius,0]) cylinder(h=thickness, r=radius);
+      translate([pcb_width+2*margin-2*radius,pcb_height+2*margin-2*radius,0]) cylinder(h=thickness, r=radius);
+    }
+    // nodges
+    translate([10, -radius, 0]) cylinder(h=thickness, d=10);
+    translate([(pcb_width+2*margin)/2-radius, -radius, 0]) cylinder(h=thickness, d=10);
+    translate([pcb_width+2*margin-2*radius-10, -radius, 0]) cylinder(h=thickness, d=10);
+    translate([10, pcb_height+2*margin-radius, 0]) cylinder(h=thickness, d=10);
+    translate([(pcb_width+2*margin)/2-radius, pcb_height+2*margin-radius, 0]) cylinder(h=thickness, d=10);
+    translate([pcb_width+2*margin-2*radius-10, pcb_height+2*margin-radius, 0]) cylinder(h=thickness, d=10);
+  }
+  // threaded inserts
+  translate([0,0,thickness-3]) {
+    translate([10, -radius-1.5, 0]) cylinder(h=3, d=3);
+    translate([(pcb_width+2*margin)/2-radius, -radius-1.5, 0]) cylinder(h=3, d=3);
+    translate([pcb_width+2*margin-2*radius-10, -radius-1.5, 0]) cylinder(h=3, d=3);
+    translate([10, pcb_height+2*margin-radius+1.5, 0]) cylinder(h=4, d=3);
+    translate([(pcb_width+2*margin)/2-radius, pcb_height+2*margin-radius+1.5, 0]) cylinder(h=4, d=3);
+    translate([pcb_width+2*margin-2*radius-10, pcb_height+2*margin-radius+1.5, 0]) cylinder(h=3, d=3);
+  }
+  // usb hole
+  translate([82-radius,-radius-10,0]) cube([18, 20, thickness]);
+  
+  translate([0,0,thickness-1]) hull() {
+    cylinder(h=1, r=inner_radius);
+    translate([pcb_width-2*inner_radius,0,0]) cylinder(h=1, r=inner_radius);
+    translate([0,pcb_height-2*inner_radius,0]) cylinder(h=1, r=inner_radius);
+    translate([pcb_width-2*inner_radius,pcb_height-2*inner_radius,0]) cylinder(h=1, r=inner_radius);
+  }
+  
+  translate([0,-radius+margin,thickness-1-1.5]) cube([64,20,1.5]);
+  translate([75,-radius+margin,thickness-1-2]) cube([18,20,2]);
+  translate([0,0,thickness-1-1]) cube([13*key_width+12*key_padding+2*key_margin, 5*key_height+4*key_padding+2*key_margin, 1]);
+}
\ No newline at end of file
diff --git a/preproto_top.scad b/preproto_top.scad
new file mode 100644
index 0000000..f5f14f5
--- /dev/null
+++ b/preproto_top.scad
@@ -0,0 +1,35 @@
+$fn = 64;
+
+radius = 7;
+pcb_width = 150.7;
+pcb_height = 64.1;
+margin = 2;
+thickness = 1;
+
+difference() {
+  union() {
+    // base shape
+    hull() {
+      cylinder(h=thickness, r=radius);
+      translate([pcb_width+2*margin-2*radius,0,0]) cylinder(h=thickness, r=radius);
+      translate([0,pcb_height+2*margin-2*radius,0]) cylinder(h=thickness, r=radius);
+      translate([pcb_width+2*margin-2*radius,pcb_height+2*margin-2*radius,0]) cylinder(h=thickness, r=radius);
+    }
+    // nodges
+    translate([10, -radius, 0]) cylinder(h=thickness, d=10);
+    translate([(pcb_width+2*margin)/2-radius, -radius, 0]) cylinder(h=thickness, d=10);
+    translate([pcb_width+2*margin-2*radius-10, -radius, 0]) cylinder(h=thickness, d=10);
+    translate([10, pcb_height+2*margin-radius, 0]) cylinder(h=thickness, d=10);
+    translate([(pcb_width+2*margin)/2-radius, pcb_height+2*margin-radius, 0]) cylinder(h=thickness, d=10);
+    translate([pcb_width+2*margin-2*radius-10, pcb_height+2*margin-radius, 0]) cylinder(h=thickness, d=10);
+  }
+  // screw holes
+  translate([10, -radius-1.5, 0]) cylinder(h=thickness, d=2);
+  translate([(pcb_width+2*margin)/2-radius, -radius-1.5, 0]) cylinder(h=thickness, d=2);
+  translate([pcb_width+2*margin-2*radius-10, -radius-1.5, 0]) cylinder(h=thickness, d=2);
+  translate([10, pcb_height+2*margin-radius+1.5, 0]) cylinder(h=thickness, d=2);
+  translate([(pcb_width+2*margin)/2-radius, pcb_height+2*margin-radius+1.5, 0]) cylinder(h=thickness, d=2);
+  translate([pcb_width+2*margin-2*radius-10, pcb_height+2*margin-radius+1.5, 0]) cylinder(h=thickness, d=2);
+  // usb hole
+  translate([82-radius,-radius-10,0]) cube([18, 20, thickness]);
+}
\ No newline at end of file