From 7ec09ac2e75c0e4c8401ac100cb6d051e0ef101b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Fredrik=20Gr=C3=B6nlund?= <fredrik.gronlund.o@gmail.com>
Date: Sat, 1 Oct 2016 14:33:28 +0200
Subject: [PATCH] added short section on IR development.
---
implementation.tex | 21 ++++++++++++++++++++-
1 file changed, 20 insertions(+), 1 deletion(-)
diff --git a/implementation.tex b/implementation.tex
index c903b03..5b55e99 100644
--- a/implementation.tex
+++ b/implementation.tex
@@ -16,4 +16,23 @@
\subsection{Resource and activity planning}
- \subsection{Time monitoring}
\ No newline at end of file
+ \subsection{Time monitoring}
+
+
+\subsection{IR Sensor development}
+ Two kinds of IR sensors were chosen as a backup, to cover for the sonar should it encounter problems in the mineshaft.
+ As the sonar has a nominal range of $\SI{2}{}$ to $\SI{400}{\centi\meter}$, both of the IR sensors were required to fully cover this range.
+ The short range IR, however, has a minimum range of $\SI{20}{\centi\meter}$.
+ Sensor response within this range coincide with response from targets much further away, leading to unreliable measurment.
+ This was deemed a non-issue, as the minimum distance overlaps with the total copter width.
+ Thus, any measurment values that could be ambiguous can be ignored, as the copter would already have crashed.
+
+ Six clusters of IR sensor pairs (long and short) were to be mounted at $90^{\circ}$ angle relative each other, pointing nominally up, down, forward, backward and to each side.
+ Thus, the double mounted IR clusters could cover the range should the sonar fail.
+
+ As development progressed, issues were found with the IR sensors.
+ Both sensors hade issues with accuracy at range, as well as low update rate, in comparison to the sonars.
+ They were also difficult to implement in software.
+ The decision was thus made that all ADC and IR development were to be put on halt in favour of SPI.
+ Additionally, the focus was to make the short-range IR sensors work first, and have them act mostly as a short-range collision avoidance system.
+ The long-ranged sensors were to be implemented either if the sonar performed poorly or if time could be spared from other parts of the project.
--
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