reword drill bit choice section

[challenge-bot] / curriculum / challenge-bot.scm

diff --git a/curriculum/challenge-bot.scm b/curriculum/challenge-bot.scm
index 2364250c7785f1185ecba9fa10116fee369ff18b..e1e942240690b0738beb4618ebf61dd95b584441 100644 (file)
--- a/curriculum/challenge-bot.scm
+++ b/curriculum/challenge-bot.scm
@@ -5,13 +5,15 @@
  :title [challenge-bot]
  (chapter
   :title [mechanical]
+  (p [let's build your robot!])
   (section
    :title [arduino to deck]
+   (p [let's attach the arduino to the deck.])
    (subsection
     :title [required materials]
     (p [you will need the things in this picture.
             ,(figure :legend "arduino to deck / required materials"
-                    (image :file "arduino-to-deck/0-required-materials.png"))
+                     (image :file "arduino-to-deck/0-required-materials.png"))
             ,(itemize
               (item [medical kit with bandages])
               (item [safety goggles])
@@ -20,31 +22,70 @@
               (item [alan wrench])
               (item [wood block])
               (item [arduino])
-              (item [#6-32x3/8\", four of them]))]))
+              (item [#6-32x3/8\", four of them])
+              (item [robot deck, the white thing with a grid of holes1]))]))
    (subsection
     :title [first hole]
     (subsubsection
-     :title [choosing drill bit])
+     :title [choosing drill bit]
+     (p [the arduino comes with holes in it already, so we will make
+             some choices around those holes.
+             choosing the right drill bit depends on what job you are
+             doing.
+             right now, we are making holes for screws to hold the
+             arduino to the deck.
+             there are two constraints between the hole and screw.
+             each hole needs to be big enough for the screw body to fit
+             through it.
+             the holes also need to be smaller than the screw's thread.
+             since there are holes on the arduino already, the screw was
+             chosen to match it.
+             the screw was chosen so that the hole on the arduino was
+             bigger than the screw body and smaller than its thread.
+             we will choose the biggest drill bit that fits through the
+             hole on the arduino, then use that to drill holes in the
+             deck.])
+     (p [here's a cross section of a screw in the deck]
+        (figure :legend "screw cross section"
+                (image :file
+                       "arduino-to-deck/screw-cross-section.png"))))
     (subsubsection
-     :title [inserting drill bit])
+     :title [inserting drill bit]
+     (p (figure :legend "arduino to deck / insert bit"
+                (image :file "arduino-to-deck/1-insert-bit.png"))
+        [insert the drill bit into the teeth of the drill.
+                insert it far enough that the teeth will clamp on the
+                smooth part of the bit when they are tightened.])
+     (p (figure
+         :legend "arduino to deck / twist tighten drill teeth"
+         (image :file "arduino-to-deck/2-twist-tighten-drill-teeth.png"))
+        [while holding the drill bit, twist end of the drill to tighten
+               the teeth.
+               make sure that the teeth end up gripping the flat part of
+               the drill bit.]))
     (subsubsection
-     :title [holding drill])
+     :title [holding drill]
+     (p [hold the drill with one hand on the handle and trigger.
+              put the other hand on the orange nozzle, before the
+              black spinning part.]))
     (subsubsection
      :title [arduino placement]
      (p [the arduino should be placed as shown in this picture.]
         (figure :legend "arduino to deck / place arduino"
-                (image :file "arduino-to-deck/3-place-arduino.png"))
-        [here's a closeup]
+                (image :file "arduino-to-deck/3-place-arduino.png")))
+     (p [here's a closeup]
         (figure :legend "arduino to deck / place arduino closeup"
-                (image :file "arduino-to-deck/4-place-arduino-closeup.png"))
-        [the arduino should line up with the holes on the deck.
-             place the arduino's top edge along the underside of the
-             deck's holes closest to the edge of the deck.
-             on the arduino, there's a hole on the top left.
-             that hole should be mid-way between two of the holes in the
-             grid of holes on the deck.
-             put the arduino hole between the third and fourth holes
-             from the left side of the deck.]))
+                (image :file
+                       "arduino-to-deck/4-place-arduino-closeup.png"))
+        [the picture above shows where to place the arduino on the deck.
+             the arduino should line up with the holes on the deck.
+             this alignment line is highlighted in pink.
+             on the arduino, there's a hole on the top left, between the
+             orange reset button and black headers.
+             the green circle shows where the hole is.
+             the blue box encloses the arduino hole and two deck holes.
+             place the arduino hole mid-way between the two
+             deck holes.]))
     (subsubsection
      :title [drilling]))
    (subsection
@@ -54,7 +95,10 @@
      (p [the "#6" part of "#6-32x3/8\"" is how big around the bolt is.
              it is related to wire gauge.
              bigger numbers mean larger screw.
-             smaller numbers means smaller screws.])
+             smaller numbers means smaller screws.]
+        (figure :legend "arduino to deck / #6-32 screw"
+                (image :file
+                       "arduino-to-deck/6-32-screw.png")))
      (p [check
          ,(itemize
            (item