Current code for Space Rocks

Here’s the current code for each Space Rock and the transmitter that they connect to. The code allows the synth programmed into each Rock to change based on the relative distance to the transmitter.

Vaporum (‘Small whale’)
Uses the Control Echo Theremin (Mozzi) synth

// include all libraries
#include <LoRaLib.h>
#include <MozziGuts.h>
#include <Oscil.h>
#include <tables/sin2048_int8.h>
#include <ControlDelay.h>
#include <RollingAverage.h>

// uncomment the following line for debug output
// NOTE: debug output will slow down Arduino!
//#define DEBUG

#ifdef DEBUG
  #define DEBUG_BEGIN(x)                Serial.begin (x)
  #define DEBUG_PRINT(x)                Serial.print (x)
  #define DEBUG_PRINT_DEC(x)            Serial.print (x, DEC)
  #define DEBUG_PRINT_HEX(x)            Serial.print (x, HEX)
  #define DEBUG_PRINTLN(x)              Serial.println (x)
  #define DEBUG_PRINT_STR(x)            Serial.print (F(x))
  #define DEBUG_PRINTLN_STR(x)          Serial.println (F(x))
#else
  #define DEBUG_BEGIN(x)
  #define DEBUG_PRINT(x)
  #define DEBUG_PRINT_DEC(x)
  #define DEBUG_PRINT_HEX(x)
  #define DEBUG_PRINTLN(x)
  #define DEBUG_PRINT_STR(x)
  #define DEBUG_PRINTLN_STR(x)
#endif

// Mozzi control rate in Hz
#define CONTROL_RATE              512

// RSSI range bounds
#define RSSI_LOW                  -60
#define RSSI_HIGH                 -30

// freqency range bounds in Hz
#define FREQ_LOW                  0
#define FREQ_HIGH                 1000

// SX1278 object instance
SX1278 lora = new LoRa;

// rolling average filter 
RollingAverage <float, 32> kAverage;

// theremin effect echo cells
unsigned int echo_cells_1 = 32;
unsigned int echo_cells_2 = 60;
unsigned int echo_cells_3 = 127;

// 2 second delay
ControlDelay <128, int> kDelay;

// oscils to compare bumpy to averaged control input
Oscil <SIN2048_NUM_CELLS, AUDIO_RATE> aSin0(SIN2048_DATA);
Oscil <SIN2048_NUM_CELLS, AUDIO_RATE> aSin1(SIN2048_DATA);
Oscil <SIN2048_NUM_CELLS, AUDIO_RATE> aSin2(SIN2048_DATA);
Oscil <SIN2048_NUM_CELLS, AUDIO_RATE> aSin3(SIN2048_DATA);

void setup(){
  // start Serial port for debugging
  DEBUG_BEGIN(115200);

  // initialize SX1278
  int state = lora.begin();
  DEBUG_PRINTLN(state);

  // set LoRa bandwidth
  state = lora.setBandwidth(250);
  DEBUG_PRINTLN(state);

  // set interrupt action
  lora.setDio0Action(setFlag);

  // start listening for LoRa transmissions
  lora.startReceive();

  // start Mozzi
  startMozzi(CONTROL_RATE);

  // set echo cells
  kDelay.set(echo_cells_1);
}

// flag to indicate that a packet was received
volatile bool receivedFlag = false;

// disable interrupt when it's not needed
volatile bool enableInterrupt = true;

void setFlag(void) {
  // check if the interrupt is enabled
  if(!enableInterrupt) {
    return;
  }

  // we got a packet, set the flag
  receivedFlag = true;
}

void updateControl(){
  // check if packet was received
  if(receivedFlag) {
    // disable the interrupt service routine while processing the data
    enableInterrupt = false;

    // reset flag
    receivedFlag = false;

    // read packet and update RSSI reading
    String str;
    lora.readData(str);

    // get raw RSSI value
    int rssiRaw = lora.lastPacketRSSI;

    // map raw RSSI value to frequency range
    int rssiMapped = map(rssiRaw, RSSI_LOW, RSSI_HIGH, FREQ_LOW, FREQ_HIGH);

    // filter frequency value
    float freqFiltered = kAverage.next(rssiMapped);

    // print RSSI values for debugging
    DEBUG_PRINT(rssiRaw);
    DEBUG_PRINT('\t');
    DEBUG_PRINT(rssiMapped);
    DEBUG_PRINT('\t');
    DEBUG_PRINTLN(freqFiltered);

    // set new frequency
    aSin0.setFreq(freqFiltered);
    aSin1.setFreq(kDelay.next(freqFiltered));
    aSin2.setFreq(kDelay.read(echo_cells_2));
    aSin3.setFreq(kDelay.read(echo_cells_3));

    // enable interrupt again
    enableInterrupt = true;
  }
}

int updateAudio(){
  return 3 * ((int)aSin0.next() + aSin1.next() + (aSin2.next() >> 1) + (aSin3.next() >> 2)) >> 3;
}

void loop(){
  audioHook();
}


Cognitum (‘Razor clam’)
Uses the Detuened Beats Wash (Mozzi) synth

// include all libraries
#include <LoRaLib.h>
#include <MozziGuts.h>
#include <Oscil.h>
#include <tables/cos8192_int8.h>
#include <mozzi_rand.h>
#include <mozzi_midi.h>
#include <mozzi_fixmath.h>
#include <RollingAverage.h>

// uncomment the following line for debug output
// NOTE: debug output will slow down Arduino!
//#define DEBUG

#ifdef DEBUG
  #define DEBUG_BEGIN(x)                Serial.begin (x)
  #define DEBUG_PRINT(x)                Serial.print (x)
  #define DEBUG_PRINT_DEC(x)            Serial.print (x, DEC)
  #define DEBUG_PRINT_HEX(x)            Serial.print (x, HEX)
  #define DEBUG_PRINTLN(x)              Serial.println (x)
  #define DEBUG_PRINT_STR(x)            Serial.print (F(x))
  #define DEBUG_PRINTLN_STR(x)          Serial.println (F(x))
#else
  #define DEBUG_BEGIN(x)
  #define DEBUG_PRINT(x)
  #define DEBUG_PRINT_DEC(x)
  #define DEBUG_PRINT_HEX(x)
  #define DEBUG_PRINTLN(x)
  #define DEBUG_PRINT_STR(x)
  #define DEBUG_PRINTLN_STR(x)
#endif

// Mozzi control rate in Hz
#define CONTROL_RATE              512

// RSSI range bounds
#define RSSI_LOW                  -60
#define RSSI_HIGH                 -30

// freqency range bounds in Hz
#define FREQ_LOW                  0
#define FREQ_HIGH                 1000

// SX1278 object instance
SX1278 lora = new LoRa;

// rolling average filter 
RollingAverage <float, 32> kAverage;

// harmonics
Oscil<COS8192_NUM_CELLS, AUDIO_RATE> aCos1(COS8192_DATA);
Oscil<COS8192_NUM_CELLS, AUDIO_RATE> aCos2(COS8192_DATA);
Oscil<COS8192_NUM_CELLS, AUDIO_RATE> aCos3(COS8192_DATA);
Oscil<COS8192_NUM_CELLS, AUDIO_RATE> aCos4(COS8192_DATA);
Oscil<COS8192_NUM_CELLS, AUDIO_RATE> aCos5(COS8192_DATA);
Oscil<COS8192_NUM_CELLS, AUDIO_RATE> aCos6(COS8192_DATA);
Oscil<COS8192_NUM_CELLS, AUDIO_RATE> aCos7(COS8192_DATA);

// duplicates but slightly off frequency for adding to originals
Oscil<COS8192_NUM_CELLS, AUDIO_RATE> aCos1b(COS8192_DATA);
Oscil<COS8192_NUM_CELLS, AUDIO_RATE> aCos2b(COS8192_DATA);
Oscil<COS8192_NUM_CELLS, AUDIO_RATE> aCos3b(COS8192_DATA);
Oscil<COS8192_NUM_CELLS, AUDIO_RATE> aCos4b(COS8192_DATA);
Oscil<COS8192_NUM_CELLS, AUDIO_RATE> aCos5b(COS8192_DATA);
Oscil<COS8192_NUM_CELLS, AUDIO_RATE> aCos6b(COS8192_DATA);
Oscil<COS8192_NUM_CELLS, AUDIO_RATE> aCos7b(COS8192_DATA);

// base pitch frequencies in 24n8 fixed int format (for speed later)
Q16n16 f1,f2,f3,f4,f5,f6,f7;

Q16n16 variation() {
  // 32 random bits & with 524287 (b111 1111 1111 1111 1111)
  // gives between 0-8 in Q16n16 format
  return  (Q16n16) (xorshift96() & 524287UL);
}

void setup(){
  // start Serial port for debugging
  DEBUG_BEGIN(115200);

  // initialize SX1278
  int state = lora.begin();
  DEBUG_PRINTLN(state);

  // set LoRa bandwidth
  state = lora.setBandwidth(250);
  DEBUG_PRINTLN(state);

  // set interrupt action
  lora.setDio0Action(setFlag);

  // start listening for LoRa transmissions
  lora.startReceive();

  // start Mozzi
  startMozzi(CONTROL_RATE);

  // select base frequencies using mtof (midi to freq) and fixed-point numbers
  f1 = Q16n16_mtof(Q16n0_to_Q16n16(48));
  f2 = Q16n16_mtof(Q16n0_to_Q16n16(74));
  f3 = Q16n16_mtof(Q16n0_to_Q16n16(64));
  f4 = Q16n16_mtof(Q16n0_to_Q16n16(77));
  f5 = Q16n16_mtof(Q16n0_to_Q16n16(67));
  f6 = Q16n16_mtof(Q16n0_to_Q16n16(57));
  f7 = Q16n16_mtof(Q16n0_to_Q16n16(60));

  // set Oscils with chosen frequencies
  aCos1.setFreq_Q16n16(f1);
  aCos2.setFreq_Q16n16(f2);
  aCos3.setFreq_Q16n16(f3);
  aCos4.setFreq_Q16n16(f4);
  aCos5.setFreq_Q16n16(f5);
  aCos6.setFreq_Q16n16(f6);
  aCos7.setFreq_Q16n16(f7);

  // set frequencies of duplicate oscillators
  aCos1b.setFreq_Q16n16(f1 + variation());
  aCos2b.setFreq_Q16n16(f2 + variation());
  aCos3b.setFreq_Q16n16(f3 + variation());
  aCos4b.setFreq_Q16n16(f4 + variation());
  aCos5b.setFreq_Q16n16(f5 + variation());
  aCos6b.setFreq_Q16n16(f6 + variation());
  aCos7b.setFreq_Q16n16(f7 + variation());
}

// flag to indicate that a packet was received
volatile bool receivedFlag = false;

// disable interrupt when it's not needed
volatile bool enableInterrupt = true;

void setFlag(void) {
  // check if the interrupt is enabled
  if(!enableInterrupt) {
    return;
  }

  // we got a packet, set the flag
  receivedFlag = true;
}

void updateControl(){
  // check if packet was received
  if(receivedFlag) {
    // disable the interrupt service routine while processing the data
    enableInterrupt = false;

    // reset flag
    receivedFlag = false;

    // read packet and update RSSI reading
    String str;
    lora.readData(str);

    // get raw RSSI value
    int rssiRaw = lora.lastPacketRSSI;

    // map raw RSSI value to frequency range
    int rssiMapped = map(rssiRaw, RSSI_LOW, RSSI_HIGH, FREQ_LOW, FREQ_HIGH);

    // filter frequency value
    float freqFiltered = kAverage.next(rssiMapped);

    // print RSSI values for debugging
    DEBUG_PRINT(rssiRaw);
    DEBUG_PRINT('\t');
    DEBUG_PRINT(rssiMapped);
    DEBUG_PRINT('\t');
    DEBUG_PRINTLN(freqFiltered);

    // change frequencies of the b oscillators
    switch(lowByte(xorshift96()) & 7) {
      case 0:
        aCos1b.setFreq_Q16n16(f1 + float_to_Q16n16(freqFiltered) + variation());
        break;
      case 1:
        aCos2b.setFreq_Q16n16(f2 + float_to_Q16n16(freqFiltered) + variation());
        break;
      case 2:
        aCos3b.setFreq_Q16n16(f3 + float_to_Q16n16(freqFiltered) + variation());
        break;
      case 3:
        aCos4b.setFreq_Q16n16(f4 + float_to_Q16n16(freqFiltered) + variation());
        break;
      case 4:
        aCos5b.setFreq_Q16n16(f5 + float_to_Q16n16(freqFiltered) + variation());
        break;
      case 5:
        aCos6b.setFreq_Q16n16(f6 + float_to_Q16n16(freqFiltered) + variation());
        break;
      case 6:
        aCos7b.setFreq_Q16n16(f7 + float_to_Q16n16(freqFiltered) + variation());
        break;
    }

    // enable interrupt again
    enableInterrupt = true;
  }
}

int updateAudio(){
  int asig =
    aCos1.next() + aCos1b.next() +
    aCos2.next() + aCos2b.next() +
    aCos3.next() + aCos3b.next() +
    aCos4.next() + aCos4b.next() +
    aCos5.next() + aCos5b.next() +
    aCos6.next() + aCos6b.next() +
    aCos7.next() + aCos7b.next();

  return asig >> 3;
}

void loop(){
  audioHook();
}


Undarum (‘Wide shell’)

Uses the Knob Light (Mozzi) synth

// include all libraries
#include <LoRaLib.h>
#include <MozziGuts.h>
#include <Oscil.h>
#include <tables/cos2048_int8.h>
#include <RollingAverage.h>

// uncomment the following line for debug output
// NOTE: debug output will slow down Arduino!
//#define DEBUG

#ifdef DEBUG
  #define DEBUG_BEGIN(x)                Serial.begin (x)
  #define DEBUG_PRINT(x)                Serial.print (x)
  #define DEBUG_PRINT_DEC(x)            Serial.print (x, DEC)
  #define DEBUG_PRINT_HEX(x)            Serial.print (x, HEX)
  #define DEBUG_PRINTLN(x)              Serial.println (x)
  #define DEBUG_PRINT_STR(x)            Serial.print (F(x))
  #define DEBUG_PRINTLN_STR(x)          Serial.println (F(x))
#else
  #define DEBUG_BEGIN(x)
  #define DEBUG_PRINT(x)
  #define DEBUG_PRINT_DEC(x)
  #define DEBUG_PRINT_HEX(x)
  #define DEBUG_PRINTLN(x)
  #define DEBUG_PRINT_STR(x)
  #define DEBUG_PRINTLN_STR(x)
#endif

// Mozzi control rate in Hz
#define CONTROL_RATE              512

// RSSI range bounds
#define RSSI_LOW                  -60
#define RSSI_HIGH                 -30

// freqency range bounds in Hz
#define FREQ_LOW                  400
#define FREQ_HIGH                 800

// SX1278 object instance
SX1278 lora = new LoRa;

// rolling average filter 
RollingAverage <float, 32> kAverage;

// Mozzi oscillators
Oscil<COS2048_NUM_CELLS, AUDIO_RATE> aCarrier(COS2048_DATA);
Oscil<COS2048_NUM_CELLS, AUDIO_RATE> aModulator(COS2048_DATA);

 // harmonics
int mod_ratio = 3;

 // carries control info from updateControl() to updateAudio()
long fm_intensity;

void setup(){
  // start Serial port for debugging
  DEBUG_BEGIN(115200);

  // initialize SX1278
  int state = lora.begin();
  DEBUG_PRINTLN(state);

  // set LoRa bandwidth
  state = lora.setBandwidth(250);
  DEBUG_PRINTLN(state);

  // set interrupt action
  lora.setDio0Action(setFlag);

  // start listening for LoRa transmissions
  lora.startReceive();

  // start Mozzi
  startMozzi(CONTROL_RATE);
}

// flag to indicate that a packet was received
volatile bool receivedFlag = false;

// disable interrupt when it's not needed
volatile bool enableInterrupt = true;

void setFlag(void) {
  // check if the interrupt is enabled
  if(!enableInterrupt) {
    return;
  }

  // we got a packet, set the flag
  receivedFlag = true;
}

void updateControl(){
  // check if packet was received
  if(receivedFlag) {
    // disable the interrupt service routine while processing the data
    enableInterrupt = false;

    // reset flag
    receivedFlag = false;

    // read packet and update RSSI reading
    String str;
    lora.readData(str);

    // get raw RSSI value
    int rssiRaw = lora.lastPacketRSSI;

    // map raw RSSI value to frequency range
    int rssiMapped = map(rssiRaw, RSSI_LOW, RSSI_HIGH, FREQ_LOW, FREQ_HIGH);

    // filter frequency value
    float freqFiltered = kAverage.next(rssiMapped);

    // print RSSI values for debugging
    DEBUG_PRINT(rssiRaw);
    DEBUG_PRINT('\t');
    DEBUG_PRINT(rssiMapped);
    DEBUG_PRINT('\t');
    DEBUG_PRINTLN(freqFiltered);

    // set new frequency
    aCarrier.setFreq(freqFiltered); 
    aModulator.setFreq(freqFiltered * mod_ratio);
    fm_intensity = freqFiltered;

    // enable interrupt again
    enableInterrupt = true;
  }
}

int updateAudio(){
  long modulation = fm_intensity * aModulator.next(); 
  return aCarrier.phMod(modulation);
}

void loop(){
  audioHook();
}


Marginis (‘Shape 4’)

Uses the Sine Wave Pulse (Mozzi) synth

// include all libraries
#include <LoRaLib.h>
#include <MozziGuts.h>
#include <Oscil.h>
#include <tables/sin2048_int8.h>
#include <Smooth.h>
#include <RollingAverage.h>

// uncomment the following line for debug output
// NOTE: debug output will slow down Arduino!
//#define DEBUG

#ifdef DEBUG
  #define DEBUG_BEGIN(x)                Serial.begin (x)
  #define DEBUG_PRINT(x)                Serial.print (x)
  #define DEBUG_PRINT_DEC(x)            Serial.print (x, DEC)
  #define DEBUG_PRINT_HEX(x)            Serial.print (x, HEX)
  #define DEBUG_PRINTLN(x)              Serial.println (x)
  #define DEBUG_PRINT_STR(x)            Serial.print (F(x))
  #define DEBUG_PRINTLN_STR(x)          Serial.println (F(x))
#else
  #define DEBUG_BEGIN(x)
  #define DEBUG_PRINT(x)
  #define DEBUG_PRINT_DEC(x)
  #define DEBUG_PRINT_HEX(x)
  #define DEBUG_PRINTLN(x)
  #define DEBUG_PRINT_STR(x)
  #define DEBUG_PRINTLN_STR(x)
#endif

// Mozzi control rate in Hz
#define CONTROL_RATE              512

// RSSI range bounds
#define RSSI_LOW                  -60
#define RSSI_HIGH                 -30

// freqency range bounds in Hz
#define FREQ_LOW                  400
#define FREQ_HIGH                 800

// SX1278 object instance
SX1278 lora = new LoRa;

// rolling average filter 
RollingAverage <float, 32> kAverage;

// Mozzi sine oscillator
Oscil <SIN2048_NUM_CELLS, AUDIO_RATE> aSin(SIN2048_DATA);

// target gain for smoothing, toggle between 255/0
byte gain = 0;

// Smoothing filter, higher number = smoother output
Smooth <long> aSmoothGain(0.9995);

void setup() {
  // start Serial port for debugging
  DEBUG_BEGIN(115200);

  // initialize SX1278
  int state = lora.begin();
  DEBUG_PRINTLN(state);

  // set LoRa bandwidth
  state = lora.setBandwidth(250);
  DEBUG_PRINTLN(state);

  // set interrupt action
  lora.setDio0Action(setFlag);

  // start listening for LoRa transmissions
  lora.startReceive();

  // start Mozzi
  startMozzi(CONTROL_RATE);

  // set output frequency to the lowest value
  aSin.setFreq(FREQ_LOW);
}

// flag to indicate that a packet was received
volatile bool receivedFlag = false;

// disable interrupt when it's not needed
volatile bool enableInterrupt = true;

void setFlag(void) {
  // check if the interrupt is enabled
  if(!enableInterrupt) {
    return;
  }

  // we got a packet, set the flag
  receivedFlag = true;
}

// variable to save starting timestamp
unsigned long start = 0;

// delay length in microseconds
unsigned long delayMicros = FREQ_LOW * 1000;

void updateControl() {
  // check if packet was received
  if(receivedFlag) {
    // disable the interrupt service routine while processing the data
    enableInterrupt = false;

    // reset flag
    receivedFlag = false;

    // read packet and update RSSI reading
    String str;
    lora.readData(str);

    // get raw RSSI value
    int rssiRaw = lora.lastPacketRSSI;

    // map raw RSSI value to frequency range
    int rssiMapped = map(rssiRaw, RSSI_LOW, RSSI_HIGH, FREQ_LOW, FREQ_HIGH);

    // filter frequency value
    float freqFiltered = kAverage.next(rssiMapped);

    // print RSSI values for debugging
    DEBUG_PRINT(rssiRaw);
    DEBUG_PRINT('\t');
    DEBUG_PRINT(rssiMapped);
    DEBUG_PRINT('\t');
    DEBUG_PRINTLN(freqFiltered);

    // set new frequency
    aSin.setFreq(freqFiltered);

    // set new delay length
    delayMicros = (FREQ_HIGH - freqFiltered) * 1000;

    // check if it's time to pulse
    if(mozziMicros() - start >= delayMicros) {
      // save current time
      start = mozziMicros();

      // flip 0/255
      gain = 255 - gain;
    }

    // enable interrupt again
    enableInterrupt = true;
  }
}

int updateAudio(){
  return (aSmoothGain.next(gain) * aSin.next()) >> 8 ;
}

void loop() {
  audioHook();
}

And the code for the transmitter, which links the four Space Rocks together.

// include library
#include <LoRaLib.h>

// SX1278 object instance
SX1278 lora = new LoRa;

void setup() {
  // start Serial port for debugging
  Serial.begin(115200);
  
  // initialize SX1278
  Serial.println(lora.begin());

  // set LoRa bandwidth
  Serial.println(lora.setBandwidth(250));

  // set output power to limit jamming
  Serial.println(lora.setOutputPower(5));
}

void loop() {
  // transmit packets as fast as we can
  lora.transmit("WeAreHere");
}

ex-XBees

So…it seems that the combination of XBee RSSI data and the Mozzi synth can only produce intermittent or pulsing sound and doesn’t allow for constant tones, as witnessed by the following video demos. All the data that has to be sent from Arduino to the XBee in order to get it to send and receive packets is causing the audio to stutter.

To get the tones required for the final piece, the circuits will need to be created using SX1278 LoRa modules instead. These will connect the four Space Rocks via an additional transmitter, and based around this circuit:

This should guarantee that the Mozzi synths can play continuous tones rather than interrupted pulses. Although I’ll now need to find a way to fit 4+”  433MHz antennaes into the Space Rocks too.

433MHz antennae
433MHz antennae