finished coursework

1 files changed, 94 insertions, 23 deletions

diff --git a/electronics/cw1/writeup.tex b/electronics/cw1/writeup.tex
index b7fad58..5dfa82d 100644
--- a/electronics/cw1/writeup.tex
+++ b/electronics/cw1/writeup.tex
@@ -10,8 +10,12 @@
 \usepackage{xcolor}
 \usepackage{graphicx} 
 \usepackage{forest} 
-\usepackage{tikz-qtree} \usepackage[siunitx, european, straightvoltages, cute inductors]{circuitikz} 
-\usepackage{setspace} \usepackage{ragged2e}
+\usepackage{tikz-qtree} 
+\usepackage[siunitx, european, straightvoltages, cute inductors]{circuitikz} 
+\usepackage{setspace} 
+\usepackage{ragged2e}
+\usepackage{graphicx}
+\graphicspath{ {./images/} }
 
 \addbibresource{ref.bib}
 
@@ -81,17 +85,30 @@
 	their tanks getting too hot, especially in the summer, my project is perfect for these fish owners.
 
 	\section{Design specification} 
+	\subsection{Design brief}
+	This project will need to achieve a few goals to be deemed as a success, they are as follows:
+	\begin{description}
+		\item[] Display a status LED to tell the user all is working as expected
+		\item[] Check the temperature against a known value
+		\item[] Have the ability to notify the user if the temperature is above the known value
+		\item[] Have the ability to inform the user if the temperature has risen above the known value and then fallen again
+		\item[] To have the system reset easily
+	\end{description}
+	If my project can meet all of these goals it will be a useable temperature sensing system, primarily designed for fish tanks,
+	but could be used in any number of temperature dependant environments.
 	\subsection{System Design} 
-	The project will need to do the following things:
+	\subsubsection{Outline of internal workings}
+	The project will need to do the following things internally to function as outlined in the design brief. These are tasks that 
+	will be ran on the microcontroller by the assembly code I need to write.
 	\begin{description}
-		\item[] Read the temprature
-		\item[] Compare the temprature to a known value
+		\item[] Read the temperature
+		\item[] Compare the temperature to a known value
 		\item[] The output is a flashing led and buzzer
 		\item[] The output is a flashing led and buzzer
 	\end{description}
-
-	My system will contain the following components to
-	function: 
+	
+	\subsubsection{Outline of component roles}
+	My system will contain the following components to function scouring to my outline of internal workings: 
 	\begin{description}
 		\item[Mircocontroller] This will be used to control all the other components \item[Thermistor] This will
 			sense the temperature 
@@ -123,19 +140,20 @@
 
 	As one can see a button will control the Microcontroller, by drawing all the current that the power supply
 	can through the button, one can make the Microcontroller reset. The Microcontroller will have 2 inputs, and
-	4 outputs. The potentiomiter will be used to set the threshold in which the warnings begin, this will be done
+	4 outputs. The potentiometer will be used to set the threshold in which the warnings begin, this will be done
 	inside the microcontroller, with a subtraction between the Thermistor value, and the potentiometer value. The
 	needed outputs will pulse to be especially clear that something is wrong.
 
-	\subsection{Flowchart}
-	Here is my code, build into an abstracted flow chart, to make the reading of the program easier. 
+	\subsection{Planning the inner workings}
+	\subsubsection{Flowchart}
+	Here is my code, built into an abstracted flow chart, to make the reading of the program easier. 
 	It is spread across 2 pages, to ensure it is big enough to read.
 
 	\begin{tikzpicture}[node distance=2cm]
 		\node (start) [startstop] {Start};
-		\node (in1) [io, below of=start] {Read temprature};
+		\node (in1) [io, below of=start] {Read temperature};
 		\node (in2) [io, below of=in1] {Read threshold value};
-		\node (dec1) [decision, below of=in2, yshift=-2cm] {Is the temprature too hot?};
+		\node (dec1) [decision, below of=in2, yshift=-2cm] {Is the temperature too hot?};
 		\node (sub1) [subroutine, right of=dec1, xshift=6cm] {Flash};
 		\node (proc1) [process, below of=dec1, yshift=-2cm, xshift=6cm] {Reset the status flag};
 
@@ -175,7 +193,7 @@
 
 
 
-	\subsection{How will it function?} 
+	\subsubsection{How will it function outside of the microcontroller?} 
 	Bellow is the diagram for my circuit, it works mostly via the code on the
 	micro controller, so this is just connecting things between live and the microcontroller.   
 	\begin{flushleft}
@@ -236,13 +254,13 @@
 	flashes at the same time; an amber LED that turns on after the flashing has stopped to inform the user that it
 	was too hot at some point; and a green status LED to inform the user that all is working.  
 
-	\subsection{The code}
-	Bellow is the code for the micro controller. It is 59 lines long and commented. It contains 12 unique instructions.
+	\subsubsection{The code controlling everything else}
+	Bellow is the code for the micro controller. It is 58 lines long and commented. It contains 12 unique instructions.
 	\lstinputlisting[]{./final.asm} 
 	This code starts with an initialisation section, that sets the micro controller's input and output pins to do
 	the correct things. Then it defines a subroutine that flashes the LED and buzzer and sets the status led. And
 	finally the main function runs in a loop to continue checking if it is too hot. 
-	\subsection{Errors in code}
+	\subsubsection{Errors in code}
 	Through out the development of project, a few errors came up in my code, I fixed them, however here is a documented
 	list of them
 	\subsubsection{Forgetting to specify the output register}
@@ -255,19 +273,72 @@
 	was to change a C to an S.
 
 	\section{System Realisation} 
+	After designing and writing the functionality, code, and the circuit it was time to build it. Here is the finished results.
 	\subsection{Circuit realisation}
-	PUT CIRCUIT PHOTO HERE
 
-	Here is my finished design prototyped on a bread board, I have cut the wires to an adequate length to ensure it is cleanly made.
-	I left the potential divider uncut, as I changed what value components I was using many times.
+	\includegraphics[width=\textwidth]{off.jpg.jpeg}	
 
-	\subsection{Calibrating the sensors} 
-	PUT PHOTOS HERE FOR CALIBRATING
+	Here is my finished design prototyped on a bread board, I have cut the wires to an adequate length to ensure it is cleanly made.
+	I left the potential divider uncut, as I changed what value components I was using many times throughout building. In this photo
+	an external (off breadboard) thermistor is being used.
+
+	I decided to use a multi-turn potentiometer instead of a traditional one, this allowed me and the end user, to calibrate the
+	system to far smaller amounts.
+
+	\subsection{Calibrating the sensors and testing the system} 
+	To calibrate my system I used water at a known temperature and a thermometer to measure. I then tuned my potentiometer to the adequate 
+	value to ensure the circuit functioned as intended.
+
+	Here is the circuit at a normal state with water at \({20}^\circ C \).
+	\\
+	\\
+	\includegraphics[width=\textwidth]{normal.jpg.jpeg}	
+	\\
+	As one can see the green LED is on at the correct time!
+	\\
+	\includegraphics[width=\textwidth]{offtemp.jpg.jpeg}	
+	\\
+	After adding more hot water one can see it switch to the higher point.
+	\\
+	\includegraphics[width=\textwidth]{hotLED.jpg.jpeg}	
+	\\
+	As the temperature rises above the \({26}^\circ C \) switching threshold the red LED begins to blink.
+	\\
+	\includegraphics[width=\textwidth]{hightemp.jpg.jpeg}	
+	\\
+	\includegraphics[width=\textwidth]{formerhot.jpg.jpeg}	
+	\\
+	As one can see after it falls back to a low temperature the amber status LED comes on to let the user know
+	it has been too hot.
+	\\
+	\includegraphics[width=\textwidth]{lowtemp.jpg.jpeg}	
+	\\
+	This temperature caused the amber LED to come on after being at \({26}^\circ C \) previously.
+	\\
 	\subsection{Results}
+	As shown in the previous sections the circuit has worked as intended, it switches at a user defined temperature, which for testing 
+	purposes I have set to \({26}^\circ C \). The tuning process is easy and simple to work with, only requiring the turning of a potentiometer.
+	This could be set out of box in a production setting, or it could be tweaked by the use to their needs.
 
 	\section{System Evaluation} 
-	\subsection{Did it work?} 
 	\subsection{What could go better?}
+	To make this system better I would have liked to make it test temperatures using a difference amplifier to compare to another known temperature as this
+	would have let me compare to room temperature, instead of set constants, this would be more helpful if the use case was slightly changed, to show relative
+	temperature, which would be helpful in a factory to show temperatures next to a machine. This however was out of the scope of this project, as I was
+	attempting to use a microcontroller to do all comparisons, a difference amplifier would have removed the need for the microcontroller, making the project 
+	irrelevant.
+
+	I also would have liked it if I could have added more features to the code, perhaps in some way adding an interrupt service to allow for further user control.
+	Perhaps as a simple clear amber status LED.
+
+	Finally I was not overly happy with my solution to resetting the microcontroller, I chose to, for a short time, short circuit the power rails of my bread board, 
+	to cut power from the microcontroller, if I were to make any edits to this system I would have replaced this with a simple MOSFET system that could keep it 
+	powered until a button was pressed. This sadly wasn't possible due to time constraints on this project. This is also caused a flaw in the 18M2 picaxe chip. The
+	original 16F88 has a reset pin, that could have been used to clear the microcontroller's state , this isn't available on the 18M2 chip.
+
+	\subsection{Conclusions}
+	Overall, including short comings, I am happy with my system. It completed my design brief of a simple temperature sensing system in a simple way. I believe this 
+	could be used for its goal of triggering alarms when fish tanks of other similar items, reach an unsafe temperature.
 
 	\newpage