From 23045a14179a47ef426971376013bd42a2191214 Mon Sep 17 00:00:00 2001 From: daniel watson Date: Wed, 8 Jun 2016 14:45:18 -0700 Subject: [PATCH] reword drill bit choice section --- curriculum/challenge-bot.scm | 29 +++++++++++++++++------------ 1 file changed, 17 insertions(+), 12 deletions(-) diff --git a/curriculum/challenge-bot.scm b/curriculum/challenge-bot.scm index 7b6eef3..e1e9422 100644 --- a/curriculum/challenge-bot.scm +++ b/curriculum/challenge-bot.scm @@ -28,18 +28,23 @@ :title [first hole] (subsubsection :title [choosing drill bit] - (p [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. - this means the hole needs to be big enough for the - screw body to fit through. - we want the screw to stay put once it's in place. - we also want the drill bit to be smaller than the - diameter of the thread. - the screw was chosen so that the hole on the arduino - was bigger than the body and smaller than the thread. - we will choose the biggest drill bit that fits through - the hole on the arduino.]) + (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 -- 2.30.2