(DA) Internet of Things and Smart Electronics- ELE3006M2122 / Mbed 2 deprecated Project-Target-Localization

Resit Target Localisation Ciaran Kane 18689005

Dependencies:   mbed

Joystick/Joystick.cpp@7:acf82069b794, 23 months ago (annotated)

Committer:
ciarankane123
Date:
Thu Aug 25 13:50:39 2022 +0000
Revision:
7:acf82069b794
Final Code;

Who changed what in which revision?

UserRevisionLine numberNew contents of line
ciarankane123 7:acf82069b794 1 #include "Joystick.h"
ciarankane123 7:acf82069b794 2
ciarankane123 7:acf82069b794 3 Joystick::Joystick(PinName vertPin,PinName horizPin,PinName clickPin)
ciarankane123 7:acf82069b794 4 {
ciarankane123 7:acf82069b794 5 vert = new AnalogIn(vertPin);
ciarankane123 7:acf82069b794 6 horiz = new AnalogIn(horizPin);
ciarankane123 7:acf82069b794 7 click = new InterruptIn(clickPin);
ciarankane123 7:acf82069b794 8 }
ciarankane123 7:acf82069b794 9
ciarankane123 7:acf82069b794 10 void Joystick::init()
ciarankane123 7:acf82069b794 11 {
ciarankane123 7:acf82069b794 12 // read centred values of joystick
ciarankane123 7:acf82069b794 13 _x0 = horiz->read();
ciarankane123 7:acf82069b794 14 _y0 = vert->read();
ciarankane123 7:acf82069b794 15
ciarankane123 7:acf82069b794 16 // this assumes that the joystick is centred when the init function is called
ciarankane123 7:acf82069b794 17 // if perfectly centred, the pots should read 0.5, but this may
ciarankane123 7:acf82069b794 18 // not be the case and x0 and y0 will be used to calibrate readings
ciarankane123 7:acf82069b794 19
ciarankane123 7:acf82069b794 20 // turn on pull-down for button -> this assumes the other side of the button
ciarankane123 7:acf82069b794 21 // is connected to +3V3 so we read 1 when pressed and 0 when not pressed
ciarankane123 7:acf82069b794 22 click->mode(PullDown);
ciarankane123 7:acf82069b794 23 // we therefore need to fire the interrupt on a rising edge
ciarankane123 7:acf82069b794 24 click->rise(callback(this,&Joystick::click_isr));
ciarankane123 7:acf82069b794 25 // need to use a callback since mbed-os5 - basically tells it to look in this class for the ISR
ciarankane123 7:acf82069b794 26 _click_flag = 0;
ciarankane123 7:acf82069b794 27
ciarankane123 7:acf82069b794 28 }
ciarankane123 7:acf82069b794 29
ciarankane123 7:acf82069b794 30 Direction Joystick::get_direction()
ciarankane123 7:acf82069b794 31 {
ciarankane123 7:acf82069b794 32 float angle = get_angle(); // 0 to 360, -1 for centred
ciarankane123 7:acf82069b794 33
ciarankane123 7:acf82069b794 34 Direction d;
ciarankane123 7:acf82069b794 35 // partition 360 into segments and check which segment the angle is in
ciarankane123 7:acf82069b794 36 if (angle < 0.0f) {
ciarankane123 7:acf82069b794 37 d = CENTRE; // check for -1.0 angle
ciarankane123 7:acf82069b794 38 } else if (angle < 22.5f) { // then keep going in 45 degree increments
ciarankane123 7:acf82069b794 39 d = N;
ciarankane123 7:acf82069b794 40 } else if (angle < 67.5f) {
ciarankane123 7:acf82069b794 41 d = NE;
ciarankane123 7:acf82069b794 42 } else if (angle < 112.5f) {
ciarankane123 7:acf82069b794 43 d = E;
ciarankane123 7:acf82069b794 44 } else if (angle < 157.5f) {
ciarankane123 7:acf82069b794 45 d = SE;
ciarankane123 7:acf82069b794 46 } else if (angle < 202.5f) {
ciarankane123 7:acf82069b794 47 d = S;
ciarankane123 7:acf82069b794 48 } else if (angle < 247.5f) {
ciarankane123 7:acf82069b794 49 d = SW;
ciarankane123 7:acf82069b794 50 } else if (angle < 292.5f) {
ciarankane123 7:acf82069b794 51 d = W;
ciarankane123 7:acf82069b794 52 } else if (angle < 337.5f) {
ciarankane123 7:acf82069b794 53 d = NW;
ciarankane123 7:acf82069b794 54 } else {
ciarankane123 7:acf82069b794 55 d = N;
ciarankane123 7:acf82069b794 56 }
ciarankane123 7:acf82069b794 57
ciarankane123 7:acf82069b794 58 return d;
ciarankane123 7:acf82069b794 59 }
ciarankane123 7:acf82069b794 60
ciarankane123 7:acf82069b794 61 // this method gets the magnitude of the joystick movement
ciarankane123 7:acf82069b794 62 float Joystick::get_mag()
ciarankane123 7:acf82069b794 63 {
ciarankane123 7:acf82069b794 64 Polar p = get_polar();
ciarankane123 7:acf82069b794 65 return p.mag;
ciarankane123 7:acf82069b794 66 }
ciarankane123 7:acf82069b794 67
ciarankane123 7:acf82069b794 68 // this method gets the angle of joystick movement (0 to 360, 0 North)
ciarankane123 7:acf82069b794 69 float Joystick::get_angle()
ciarankane123 7:acf82069b794 70 {
ciarankane123 7:acf82069b794 71 Polar p = get_polar();
ciarankane123 7:acf82069b794 72 return p.angle;
ciarankane123 7:acf82069b794 73 }
ciarankane123 7:acf82069b794 74
ciarankane123 7:acf82069b794 75 // get raw joystick coordinate in range -1 to 1
ciarankane123 7:acf82069b794 76 // Direction (x,y)
ciarankane123 7:acf82069b794 77 // North (0,1)
ciarankane123 7:acf82069b794 78 // East (1,0)
ciarankane123 7:acf82069b794 79 // South (0,-1)
ciarankane123 7:acf82069b794 80 // West (-1,0)
ciarankane123 7:acf82069b794 81 Vector2D Joystick::get_coord()
ciarankane123 7:acf82069b794 82 {
ciarankane123 7:acf82069b794 83 // read() returns value in range 0.0 to 1.0 so is scaled and centre value
ciarankane123 7:acf82069b794 84 // substracted to get values in the range -1.0 to 1.0
ciarankane123 7:acf82069b794 85 float x = 2.0f*( horiz->read() - _x0 );
ciarankane123 7:acf82069b794 86 float y = 2.0f*( vert->read() - _y0 );
ciarankane123 7:acf82069b794 87
ciarankane123 7:acf82069b794 88 // Note: the x value here is inverted to ensure the positive x is to the
ciarankane123 7:acf82069b794 89 // right. This is simply due to how the potentiometer on the joystick
ciarankane123 7:acf82069b794 90 // I was using was connected up. It could have been corrected in hardware
ciarankane123 7:acf82069b794 91 // by swapping the power supply pins. Instead it is done in software so may
ciarankane123 7:acf82069b794 92 // need to be changed depending on your wiring setup
ciarankane123 7:acf82069b794 93
ciarankane123 7:acf82069b794 94 Vector2D coord = {-x,y};
ciarankane123 7:acf82069b794 95 return coord;
ciarankane123 7:acf82069b794 96 }
ciarankane123 7:acf82069b794 97
ciarankane123 7:acf82069b794 98 // This maps the raw x,y coord onto a circular grid.
ciarankane123 7:acf82069b794 99 // See: http://mathproofs.blogspot.co.uk/2005/07/mapping-square-to-circle.html
ciarankane123 7:acf82069b794 100 Vector2D Joystick::get_mapped_coord()
ciarankane123 7:acf82069b794 101 {
ciarankane123 7:acf82069b794 102 Vector2D coord = get_coord();
ciarankane123 7:acf82069b794 103
ciarankane123 7:acf82069b794 104 // do the transformation
ciarankane123 7:acf82069b794 105 float x = coord.x*sqrt(1.0f-pow(coord.y,2.0f)/2.0f);
ciarankane123 7:acf82069b794 106 float y = coord.y*sqrt(1.0f-pow(coord.x,2.0f)/2.0f);
ciarankane123 7:acf82069b794 107
ciarankane123 7:acf82069b794 108 Vector2D mapped_coord = {x,y};
ciarankane123 7:acf82069b794 109 return mapped_coord;
ciarankane123 7:acf82069b794 110 }
ciarankane123 7:acf82069b794 111
ciarankane123 7:acf82069b794 112 // this function converts the mapped coordinates into polar form
ciarankane123 7:acf82069b794 113 Polar Joystick::get_polar()
ciarankane123 7:acf82069b794 114 {
ciarankane123 7:acf82069b794 115 // get the mapped coordinate
ciarankane123 7:acf82069b794 116 Vector2D coord = get_mapped_coord();
ciarankane123 7:acf82069b794 117
ciarankane123 7:acf82069b794 118 // at this point, 0 degrees (i.e. x-axis) will be defined to the East.
ciarankane123 7:acf82069b794 119 // We want 0 degrees to correspond to North and increase clockwise to 359
ciarankane123 7:acf82069b794 120 // like a compass heading, so we need to swap the axis and invert y
ciarankane123 7:acf82069b794 121 float x = coord.y;
ciarankane123 7:acf82069b794 122 float y = coord.x;
ciarankane123 7:acf82069b794 123
ciarankane123 7:acf82069b794 124 float mag = sqrt(x*x+y*y); // pythagoras
ciarankane123 7:acf82069b794 125 float angle = RAD2DEG*atan2(y,x);
ciarankane123 7:acf82069b794 126 // angle will be in range -180 to 180, so add 360 to negative angles to
ciarankane123 7:acf82069b794 127 // move to 0 to 360 range
ciarankane123 7:acf82069b794 128 if (angle < 0.0f) {
ciarankane123 7:acf82069b794 129 angle+=360.0f;
ciarankane123 7:acf82069b794 130 }
ciarankane123 7:acf82069b794 131
ciarankane123 7:acf82069b794 132 // the noise on the ADC causes the values of x and y to fluctuate slightly
ciarankane123 7:acf82069b794 133 // around the centred values. This causes the random angle values to get
ciarankane123 7:acf82069b794 134 // calculated when the joystick is centred and untouched. This is also when
ciarankane123 7:acf82069b794 135 // the magnitude is very small, so we can check for a small magnitude and then
ciarankane123 7:acf82069b794 136 // set the angle to -1. This will inform us when the angle is invalid and the
ciarankane123 7:acf82069b794 137 // joystick is centred
ciarankane123 7:acf82069b794 138
ciarankane123 7:acf82069b794 139 if (mag < TOL) {
ciarankane123 7:acf82069b794 140 mag = 0.0f;
ciarankane123 7:acf82069b794 141 angle = -1.0f;
ciarankane123 7:acf82069b794 142 }
ciarankane123 7:acf82069b794 143
ciarankane123 7:acf82069b794 144 Polar p = {mag,angle};
ciarankane123 7:acf82069b794 145 return p;
ciarankane123 7:acf82069b794 146 }
ciarankane123 7:acf82069b794 147
ciarankane123 7:acf82069b794 148 bool Joystick::button_pressed()
ciarankane123 7:acf82069b794 149 {
ciarankane123 7:acf82069b794 150 // ISR must have been triggered
ciarankane123 7:acf82069b794 151 if (_click_flag) {
ciarankane123 7:acf82069b794 152 _click_flag = 0; // clear flag
ciarankane123 7:acf82069b794 153 return true;
ciarankane123 7:acf82069b794 154 } else {
ciarankane123 7:acf82069b794 155 return false;
ciarankane123 7:acf82069b794 156 }
ciarankane123 7:acf82069b794 157 }
ciarankane123 7:acf82069b794 158
ciarankane123 7:acf82069b794 159 void Joystick::click_isr()
ciarankane123 7:acf82069b794 160 {
ciarankane123 7:acf82069b794 161 _click_flag = 1;
ciarankane123 7:acf82069b794 162 }