add caster

diff --git a/guide/4-caster-to-deck.ogv b/guide/4-caster-to-deck.ogv
new file mode 100644 (file)
index 0000000..275e3c1
Binary files /dev/null and b/guide/4-caster-to-deck.ogv differ

diff --git a/guide/challenge-bot.scm b/guide/challenge-bot.scm
index da614d50dfe9b505dba0c5faaee74a4fed9cebf6..9ea816f7dc8eb1a972b7dabf0a1b87a027a568f5 100644 (file)
--- a/guide/challenge-bot.scm
+++ b/guide/challenge-bot.scm
@@ -565,16 +565,23 @@
              as you can while tightening it down.
              this will give more clearance to the wheels of the robot
              so they do not rub the deck.])))
+  (section
+   :title [caster]
+   (p [the caster will go at the back of the robot and provide a third
+           point of contact for the robot, making it easier for it to
+           balance.])
+   (figure
+    :legend "caster"
+    (video :file "4-caster-to-deck.ogv"))
+   (p [check])
+   (enumerate
+    (item [what would happen if the robot did not have a caster?])))
   (section
    :title [wheels]
    (subsection
     :title [tread])
    (subsection
     :title [motor]))
-  (section
-   :title [caster]
-   (subsection
-    :title [deck placement]))
   (section
    :title [sonars]
    (subsection