How to Make Volume Control with Digispark

1// see tutorial at http://learn.adafruit.com/trinket-usb-volume-knob
2
3#include  "TrinketHidCombo.h"
4#define turningRight 1
5#define turningLeft 0
6
7
8
9#define  PIN_ENCODER_A 2
10#define PIN_ENCODER_B 0
11#define ATTINY_PINx  PINB
12#define  PIN_ENCODER_SWITCH 1
13#define numberOfStates 4
14
15static uint8_t enc_prev_pos   = 0;
16static uint8_t enc_flags      = 0;
17static char    sw_was_pressed =  0;
18uint8_t state = 3-1;
19bool startup = true;
20const char * stateType[] =  { "arrow shift", "media", "premiere pro", "photoshop" };
21
22//clicking  variables
23static long holdTime      = 500;
24static long longHoldTime   = 700;
25unsigned  long buttonTimer = 0;
26unsigned long doubleClickTimer = 0;
27bool checkForDoubleClick  = false;
28
29void setup() {
30  // set pins as input with internal pull-up resistors  enabled
31  pinMode(PIN_ENCODER_A, INPUT);
32  pinMode(PIN_ENCODER_B, INPUT);
33  digitalWrite(PIN_ENCODER_A, HIGH);
34  digitalWrite(PIN_ENCODER_B, HIGH);
35
36  pinMode(PIN_ENCODER_SWITCH, INPUT);
37  // the switch is active-high, not active-low
38  // since it shares the pin with Trinket's built-in LED
39  // the LED acts as  a pull-down resistor
40  digitalWrite(PIN_ENCODER_SWITCH, HIGH);
41
42  TrinketHidCombo.begin();  // start the USB device engine and enumerate
43
44  // get an initial reading  on the encoder pins
45  if (digitalRead(PIN_ENCODER_A) == LOW) {
46    enc_prev_pos  |= (1 << 0);
47  }
48  if (digitalRead(PIN_ENCODER_B) == LOW) {
49    enc_prev_pos  |= (1 << 1);
50  }
51}
52
53void loop() {
54  int8_t enc_action = 0; // 1 or  -1 if moved, sign is direction
55
56  // note: for better performance, the code  will now use
57  // direct port access techniques
58  // http://www.arduino.cc/en/Reference/PortManipulation
59  uint8_t enc_cur_pos = 0;
60  // read in the encoder state first
61  if (bit_is_clear(ATTINY_PINx,  PIN_ENCODER_A)) {
62    enc_cur_pos |= (1 << 0);
63  }
64  if (bit_is_clear(ATTINY_PINx,  PIN_ENCODER_B)) {
65    enc_cur_pos |= (1 << 1);
66  }
67
68  // if any rotation  at all
69  if (enc_cur_pos != enc_prev_pos) {
70    if (enc_prev_pos == 0x00)  {
71      // this is the first edge
72      if (enc_cur_pos == 0x01) {
73        enc_flags  |= (1 << 0);
74      }
75      else if (enc_cur_pos == 0x02) {
76        enc_flags  |= (1 << 1);
77      }
78    }
79
80    if (enc_cur_pos == 0x03) {
81      //  this is when the encoder is in the middle of a "step"
82      enc_flags |= (1  << 4);
83    }
84    else if (enc_cur_pos == 0x00) {
85      // this is the final  edge
86      if (enc_prev_pos == 0x02) {
87        enc_flags |= (1 << 2);
88      }
89      else if (enc_prev_pos == 0x01) {
90        enc_flags |= (1 <<  3);
91      }
92
93      // check the first and last edge
94      // or maybe  one edge is missing, if missing then require the middle state
95      // this will  reject bounces and false movements
96      if (bit_is_set(enc_flags, 0) && (bit_is_set(enc_flags,  2) || bit_is_set(enc_flags, 4))) {
97        enc_action = 1;
98      }
99      else  if (bit_is_set(enc_flags, 2) && (bit_is_set(enc_flags, 0) || bit_is_set(enc_flags,  4))) {
100        enc_action = 1;
101      }
102      else if (bit_is_set(enc_flags,  1) && (bit_is_set(enc_flags, 3) || bit_is_set(enc_flags, 4))) {
103        enc_action  = -1;
104      }
105      else if (bit_is_set(enc_flags, 3) && (bit_is_set(enc_flags,  1) || bit_is_set(enc_flags, 4))) {
106        enc_action = -1;
107      }
108
109      enc_flags = 0; // reset for next time
110    }
111  }
112
113  enc_prev_pos  = enc_cur_pos;
114
115  if (enc_action > 0) turnAction(turningRight);
116  else  if (enc_action < 0) turnAction(turningLeft);
117
118
119  if (bit_is_set(ATTINY_PINx,  PIN_ENCODER_SWITCH)) {
120    if (sw_was_pressed == 0) {// only on initial press,  so the keystroke is not repeated while the button is held down
121
122    }
123    sw_was_pressed = 1;
124  }
125  else {
126    if (sw_was_pressed != 0) {
127      buttonTimer = millis();
128      while (!digitalRead(PIN_ENCODER_SWITCH));
129      if (millis() - buttonTimer > longHoldTime) {
130        state++;
131        if  (state > numberOfStates - 1)state = 0; //cycle modes (n) in n-1
132        printOut(stateType[state]);
133      }
134      else {
135        if (!checkForDoubleClick) {
136          checkForDoubleClick  = true;
137          doubleClickTimer = millis();
138        }
139        else if  (millis() - doubleClickTimer < holdTime && checkForDoubleClick) {
140          clickAction(true);
141          checkForDoubleClick = false;
142          doubleClickTimer = 0;
143        }
144      }
145      delay(5); // debounce delay
146    }
147    sw_was_pressed = 0;
148  }
149  if (checkForDoubleClick) {
150    if (millis() - doubleClickTimer > holdTime)  {
151      clickAction(false);
152      checkForDoubleClick = false;
153      doubleClickTimer  = 0;
154    }
155  }
156  TrinketHidCombo.poll(); // check if USB needs anything  done
157}
158
159
160void printOut(const char* c) {
161  TrinketHidCombo.pressKey(KEYCODE_MOD_LEFT_GUI,  KEYCODE_R);
162  TrinketHidCombo.pressKey(0, 0);
163  delay(200);
164  TrinketHidCombo.print(c);
165  delay(500);
166  TrinketHidCombo.pressKey(0,KEYCODE_ESC);
167  TrinketHidCombo.pressKey(0,  0);
168  delay(5); // debounce delay
169}
170
171