add ebox_hook to README

README.md

@@ -23,6 +23,12 @@ OpenSCAD code for the project box housing the PCBA is in the [scad/box/](scad/bo
 
 ![EBox design in OpenSCAD](images/scad-plant133-ebox.png)
 
+### Project box reservoir hanger
+
+Code for a plate which allows you to hang the EBox on the side of a water reservoir is in [scad/ebox_hook](scad/ebox_hook). This is screwed to the bottom part of the EBox.
+
+![Reservoir hanger](images/ebox-reservoir-hook.png)
+
 ### Reservoir insert
 
 Inside the water reservoir, an insert holds a float for detecting the water level and 1-4 aquarium pumps for watering the plants.  The code for this insert is in [scad/reservoir_insert](scad/reservoir_insert).

scad/ebox_hook/README.md

@@ -0,0 +1 @@
+This is a plate you can screw the EBox bottom onto, which then allows you to hang the EBox on the side of a water reservoir.

scad/ebox_hook/hook.scad

@@ -0,0 +1,39 @@
+include <../box/board.scad>
+include <../box/box.scad>
+
+epsilon = 0.01;
+
+screw_head_height = 2;
+wall_thickness = 1;
+reservoir_thickness = 3;
+gap = 0.2;
+
+module plantl33_hook() {
+  module recessed_hole() {
+    w = 2;
+    d = screw_head_height + wall_thickness;
+    translate([0, 0, -epsilon]) {
+      cylinder(d+1, 1.5, 1.5);
+      cylinder(screw_head_height, 4, 4);
+    }
+  }
+
+  union() {
+    // Ebox mount plate.
+    difference() {
+      $fn = 40;
+      cube([inner_dims[0]+2, inner_dims[1], wall_thickness+screw_head_height]);
+      // Screw holes fox ebox;
+      translate([-0, -5, 0]) {
+	translate([15, 15, 0]) recessed_hole();
+	translate([40, 40, 0]) recessed_hole();
+      }
+    }
+    sep = wall_thickness+reservoir_thickness+gap*2;
+    // Inside reservoir.
+    translate([0, 0, -sep]) cube([5, inner_dims[1], wall_thickness]);
+    // Top of the hook, spaning the reservoir wall.
+    translate([-wall_thickness+epsilon, 0, -sep]) 
+      cube([wall_thickness, inner_dims[1], wall_thickness+sep+screw_head_height]);
+  }
+}

scad/ebox_hook/print_hook.scad

@@ -0,0 +1,3 @@
+include <hook.scad>
+
+plantl33_hook();