Finished bonus section

Created blank .tex document
Added images to resources folder.

src/ArduinoPyPlot.py

@@ -1,112 +0,0 @@
-"""
-ldr.py
-Display analog data from Arduino using Python (matplotlib)
-Author: Mahesh Venkitachalam
-Website: electronut.in
-"""
-
-import sys, serial, argparse
-import numpy as np
-from time import sleep
-from collections import deque
-
-import matplotlib.pyplot as plt
-import matplotlib.animation as animation
-
-
-# plot class
-class AnalogPlot:
-  # constr
-  def __init__(self, strPort, maxLen):
-      # open serial port
-      self.ser = serial.Serial(strPort, 9600)
-
-      self.ax = deque([0.0]*maxLen)
-      self.ay = deque([0.0]*maxLen)
-      self.maxLen = maxLen
-
-  # add to buffer
-  def addToBuf(self, buf, val):
-      if len(buf) < self.maxLen:
-          buf.append(val)
-      else:
-          buf.pop()
-          buf.appendleft(val)
-
-  # add data
-  def add(self, data):
-      assert(len(data) == 2)
-      self.addToBuf(self.ax, data[0])
-      self.addToBuf(self.ay, data[1])
-
-  # update plot
-  def update(self, frameNum, a0, a1):
-      try:
-          line = self.ser.readline()
-          data = [float(val) for val in line.split()]
-          # print data
-          if(len(data) == 2 and not pause):
-              self.add(data)
-              a0.set_data(range(self.maxLen), self.ax)
-              a1.set_data(range(self.maxLen), 0)
-      except KeyboardInterrupt:
-          print('exiting')
-
-      if not pause:
-        return a0,
-
-  # clean up
-  def close(self):
-      # close serial
-      self.ser.flush()
-      self.ser.close()
-
-pause = False
-def onClick(event):
-    global pause
-    pause = not pause
-
-# main() function
-def main():
-  # create parser
-  parser = argparse.ArgumentParser(description="LDR serial")
-  # add expected arguments
-  parser.add_argument('--port', dest='port', required=True)
-
-  # parse args
-  args = parser.parse_args()
-
-  #strPort = '/dev/tty.usbserial-A7006Yqh'
-  strPort = args.port
-
-  print('reading from serial port %s...' % strPort)
-
-  # plot parameters
-  analogPlot = AnalogPlot(strPort, 300)
-
-  print('plotting data...')
-
-  # set up animation
-  fig = plt.figure()
-
-  ax = plt.axes(xlim=(0, 300), ylim=(0, 1023))
-  a0, = ax.plot([], [])
-  a1, = ax.plot([], [])
-  fig.canvas.mpl_connect('button_press_event', onClick)
-  anim = animation.FuncAnimation(fig, analogPlot.update,
-                                 fargs=(a0, a1),
-                                 frames=None,
-                                 interval=50)
-
-  # show plot
-  plt.show()
-
-  # clean up
-  analogPlot.close()
-
-  print('exiting.')
-
-
-# call main
-if __name__ == '__main__':
-  main()

src/sketch.ino

@@ -1,29 +0,0 @@
-
-// analog-plot
-// 
-// Read analog values from A0 and A1 and print them to serial port.
-//
-// electronut.in
-
-#include "Arduino.h"
-
-void setup()
-{
-  // initialize serial comms
-  Serial.begin(9600); 
-}
-
-void loop()
-{
-  // read A0
-  int val1 = analogRead(0);
-  // read A1
-  int val2 = analogRead(1);
-  // print to serial
-  Serial.print(val1);
-  Serial.print(" ");
-  Serial.print(val2);
-  Serial.print("\n");
-  // wait 
-  delay(50);
-}

writeup.tex

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+\documentclass[titlepage]{scrartcl}
+\usepackage{enumitem}
+\usepackage[british]{babel}
+\usepackage[style=apa, backend=biber]{biblatex}
+\DeclareLanguageMapping{british}{british-apa}
+\usepackage{url}
+\usepackage{float}
+\usepackage[labelformat=empty]{caption}
+\restylefloat{table}
+\usepackage{perpage}
+\MakePerPage{footnote}
+\usepackage{abstract}
+\usepackage{graphicx}
+% Create hyperlinks in bibliography
+\usepackage{hyperref}
+\usepackage{amsmath}
+
+\usepackage[T1]{fontenc}
+\usepackage[utf8]{inputenc}
+\usepackage{blindtext}
+\setkomafont{disposition}{\normalfont\bfseries}
+
+\graphicspath{
+    {./resources/},
+}
+\addbibresource{~/Documents/library.bib}
+
+\newsavebox{\abstractbox}
+\renewenvironment{abstract}
+  {\begin{lrbox}{0}\begin{minipage}{\textwidth}
+   \begin{center}\normalfont\sectfont\abstractname\end{center}\quotation}
+  {\endquotation\end{minipage}\end{lrbox}%
+   \global\setbox\abstractbox=\box0 }
+
+\usepackage{etoolbox}
+\makeatletter
+\expandafter\patchcmd\csname\string\maketitle\endcsname
+  {\vskip\z@\@plus3fill}
+  {\vskip\z@\@plus2fill\box\abstractbox\vskip\z@\@plus1fill}
+  {}{}
+\makeatother
+
+\DeclareCiteCommand{\citeyearpar}
+    {}
+    {\mkbibparens{\bibhyperref{\printdate}}}
+    {\multicitedelim}
+    {}
+
+\begin{document}
+    \title{ECS742\\Interactive Digital Media Techniques\\Mini-Assignment 1: Arduino}
+    \subtitle{\LARGE{Technical Report}}
+    \author{Sam Perry\\Student Number: 160842984}
+    \date{}
+    \maketitle
+
+    \section{Connecting and reading the FSR}
+    Initially, a circuit was created to demonstrate the reading of values from
+    the FSR (Force Sensitive Resistor).  A 5V supply was used to pass a current
+    through the resistor, which was measured via analog input 0.  A 10kohm
+    pull-down resistor was connected to ground between the FSR and the input.
+    This was necessary to avoid a direct connection between the 5V supply and
+    ground at points when the FSR provides little to no resistance. This also
+    creates a consistently low value to input when resistance from the FSR
+    is high, avoiding unpredictable floating readings caused by a disconnected
+    input.\\
+    \begin{figure}[H]
+        \makebox[\textwidth]{\includegraphics[width=0.35\textwidth]{Step1}}
+    \end{figure}
+
+    Code was written to print values to the serial port. A Python script was
+    used to record these values as shown:
+    \begin{figure}[H]
+        \caption{Value measured over time. A sharp increase in pressure followed by a gradual release is displayed.}
+        \makebox[\textwidth]{\includegraphics[width=0.75\textwidth]{FSR_Linearity}}
+    \end{figure}
+
+    From these readings it can be seen that there is a non-linear relationship
+    between applied pressure and measurement. As the voltage measured is
+    proportional to the inverse of the FSR resistance \parencite{ada2016},
+    voltage increases at what appears to be an exponentially decreasing rate as
+    resistance increase at the same rate.
+
+    \section{Using the FSR values to create a tone}
+    Building on the circuit developed in step 1, a speaker was attached. The
+    speaker was connected to digital output 8 and to ground. Code was written
+    to read input from the FSR, scale values to fall between pre-determined
+    high and low values, and output a tone of the frequency specified for 20ms. 
+    The result is an instrument that outputs rapid short tones that increase in
+    pitch based on pressure applied.
+
+    \begin{figure}[H]
+        \makebox[\textwidth]{\includegraphics[width=0.35\textwidth]{Step2}}
+    \end{figure}
+
+    The speaker is capable of producing tones as low as around 100hz. Below
+    this, the tone begins to lose it's tonal quality and the rhythmic
+    characteristics become more prominent. The speaker can also produce tones
+    as high as around 10Khz, however perceived loudness deteriorates beyond
+    5-6Khz.\\
+    The instruments is capable of producing interesting melodies and has a
+    tactile response. However the lack of control over amplitude and the
+    inaccuracy of the resistor result in difficulties when trying to perform a
+    sequence of specific notes. This could be improved reducing the range of
+    playable frequencies. This would allow for greater pitch accuracy at a cost
+    of a lower range of possible tones.
+
+    \section{Using buttons to make a simple keyboard}
+    Buttons were then added to the instrument. This allows a user to play 8
+    tones in a chromatic scale. Each button was attached to the circuit in a
+    similar fashion to that of the FSK. Pull down resistors were used and each
+    button was assigned a digital input, allowing the arduino to determine the
+    state of the button as being on (HIGH) or off (LOW). Although this method
+    worked corectly, an alternative method using a "resistor ladder" is
+    detailed in the arduino projects book~\parencite[p.79]{arduino2015}. This
+    would allow for the same performance, whilst using only one analog input as
+    opposed to the 8 digital inputs as used in this implementation.  The
+    arduino was then programmed to iterate across buttons until an active
+    button was found. An array of note frequencies would then be accessed by
+    index to determine the button's note frequency. This could then be played
+    through the built in tone function using the speaker.\\
+
+    \begin{figure}[H]
+        \makebox[\textwidth]{\includegraphics[width=0.35\textwidth]{Step3}}
+    \end{figure}
+
+    The instrument is now able to play precise tones with far greater accuracy
+    than was possible using the FSR. However, this comes at the cost of the
+    tactile and expressive control offered by the FSR. The limit of available
+    notes and lack of touch sensitivity make for an unintuitive playing
+    experience.
+
+    \section{Adding vibrato using the FSR}
+    Vibrato was added to the keyboard instrument by scaling the values from the
+    FSR based on the output pitch. By calculating the output pitch +/- 5\%, the
+    pitch could be modulated by scaling FSR values to within these upper and
+    lower boundaries. This allows the user to vary the pitch with the
+    expressivity of the FSR whilst maintaining a degree of accuracy from the
+    button based input. A issue arises in the FSR resting at it's lowest value,
+    forcing a player to modulate upwards from -5\% rather than beginning at the
+    pitch specified by the button. This may cause issues for a performer with
+    regards to staying in tune, as a performer would have to consistently apply
+    pressure to stay at the centre frequency of any given note. An
+    alternative would be to start at the desired frequency and bend up or down
+    only, although this may alter the pitch too far from the initial pitch.
+    Another alternative might be to have two FSRs, one for each direction.
+    However, this would not allow for the same level of smoothness around the
+    centre frequency due to the need to switch.
+
+    \section{Bonus - Melody Playback}
+    Melody playback was implemented by iterating over an array of note indexes
+    on each button press. Button state was stored in a variable to allow melody
+    position to be incremented over repeated presses of the button. Melody
+    position was reset to 0 at the end of each loop to allow for continuous
+    looping of the melody.
+
+    \printbibliography
+\end{document}