Jonathan Jones / Mbed 2 deprecated Attendance Bot 5000

Hacking into the iClicker2 for adding remote access abilities. http://www.amazon.com/I-Clicker-2-I-CLICKER/dp/1429280476

Dependencies:   mbed

Speaker.h@2:77c859f607ac, 2014-12-09 (annotated)

Committer:
sjsm3
Date:
Tue Dec 09 13:43:26 2014 +0000
Revision:
2:77c859f607ac
added speaker functionality

Who changed what in which revision?

UserRevisionLine numberNew contents of line
sjsm3 2:77c859f607ac 1 class Speaker
sjsm3 2:77c859f607ac 2 {
sjsm3 2:77c859f607ac 3 public:
sjsm3 2:77c859f607ac 4 Speaker(PinName pin) : _pin(pin) {
sjsm3 2:77c859f607ac 5 // _pin(pin) means pass pin to the Speaker Constructor
sjsm3 2:77c859f607ac 6 // precompute 32 sample points on one sine wave cycle
sjsm3 2:77c859f607ac 7 // used for continuous sine wave output later
sjsm3 2:77c859f607ac 8 for(int k=0; k<32; k++) {
sjsm3 2:77c859f607ac 9 Analog_out_data[k] = int (65536.0 * ((1.0 + sin((float(k)/32.0*6.28318530717959)))/2.0));
sjsm3 2:77c859f607ac 10 // scale the sine wave to 16-bits - as needed for AnalogOut write_u16 arg
sjsm3 2:77c859f607ac 11 }
sjsm3 2:77c859f607ac 12
sjsm3 2:77c859f607ac 13 }
sjsm3 2:77c859f607ac 14 // class method to play a note based on AnalogOut class
sjsm3 2:77c859f607ac 15 void PlayNote(float frequency, float duration, float volume) {
sjsm3 2:77c859f607ac 16 // scale samples using current volume level arg
sjsm3 2:77c859f607ac 17 for(int k=0; k<32; k++) {
sjsm3 2:77c859f607ac 18 Analog_scaled_data[k] = Analog_out_data[k] * volume;
sjsm3 2:77c859f607ac 19 }
sjsm3 2:77c859f607ac 20 // reset to start of sample array
sjsm3 2:77c859f607ac 21 i=0;
sjsm3 2:77c859f607ac 22 // turn on timer interrupts to start sine wave output
sjsm3 2:77c859f607ac 23 Sample_Period.attach(this, &Speaker::Sample_timer_interrupt, 1.0/(frequency*32.0));
sjsm3 2:77c859f607ac 24 // play note for specified time
sjsm3 2:77c859f607ac 25 wait(duration);
sjsm3 2:77c859f607ac 26 // turns off timer interrupts
sjsm3 2:77c859f607ac 27 Sample_Period.detach();
sjsm3 2:77c859f607ac 28 // sets output to mid range - analog zero
sjsm3 2:77c859f607ac 29 this->_pin.write_u16(32768);
sjsm3 2:77c859f607ac 30
sjsm3 2:77c859f607ac 31 }
sjsm3 2:77c859f607ac 32 private:
sjsm3 2:77c859f607ac 33 // sets up specified pin for analog using AnalogOut class
sjsm3 2:77c859f607ac 34 AnalogOut _pin;
sjsm3 2:77c859f607ac 35 // set up a timer to be used for sample rate interrupts
sjsm3 2:77c859f607ac 36 Ticker Sample_Period;
sjsm3 2:77c859f607ac 37
sjsm3 2:77c859f607ac 38 //variables used by interrupt routine and PlayNote
sjsm3 2:77c859f607ac 39 volatile int i;
sjsm3 2:77c859f607ac 40 short unsigned Analog_out_data[32];
sjsm3 2:77c859f607ac 41 short unsigned Analog_scaled_data[32];
sjsm3 2:77c859f607ac 42
sjsm3 2:77c859f607ac 43 // Interrupt routine
sjsm3 2:77c859f607ac 44 // used to output next analog sample whenever a timer interrupt occurs
sjsm3 2:77c859f607ac 45 void Sample_timer_interrupt(void) {
sjsm3 2:77c859f607ac 46 // send next analog sample out to D to A
sjsm3 2:77c859f607ac 47 this->_pin.write_u16(Analog_scaled_data[i]);
sjsm3 2:77c859f607ac 48 // increment pointer and wrap around back to 0 at 32
sjsm3 2:77c859f607ac 49 i = (i+1) & 0x01F;
sjsm3 2:77c859f607ac 50 }
sjsm3 2:77c859f607ac 51 };