Adrian Freed

The current growth of the Arduino platform is fueled by the many new boards that make it easier to squeeze Atmega processors and their associated peripherals into ever smaller spaces or unusual places such as clothing. Neather hoarding or fetishism explain my large and growing collection of Arduinos (official and unofficial) - I use them to test the sketches and libraries that I share and to teach people how to pick the best one for their applications in

Dates:Saturday May 15 and Sunday May 16, 2010

from 10am to 5pm

Description

Now that I have assembled one of the largest collection of e-textile materials and associated tools I am trying to figure out the smallest winning subset that can form a portable lab.

Not my first publication, but my first one with some challenging engineering. I did this in my late teens and it was published in a hobby electronics magazine, "Electronics Australia". https://adrianfreed.com/content/audio-oscillator-using-digital-ics

I discovered by accident that some folk from Greece published the same ideas in a professional technical journal in 1989 (attached). If you are a scholar of such things it is interesting to compare and contrast the modes of articulation in my vernacular engineering approach with those of the academic paper.

As I review this design from the 1970's I am struck by the exotic mixture of TTL/CMOS logic/CMOS switches, transistors and opamps that were required to pull it off. Although it might seem that such techniques are obsolete, I have seen plenty of recent Arduino designs using resistor networks that have faced the same challenge of creating a function with positive and negative values from binary sources.

Q: How would I do it differently today? A: I would replace the 555 timer and TTL parts for an Arduino and use a rail to rail inverting opamp.

Interestingly the parts required are all still available and the Arduino solution would cost about the same. The main cost difference would probably be from the the two-pole multiway switches which are expensive these days.

This controller demonstrates how most resistive touch screen systems can be modified to provide independent sensing of two positions on the surface. A single pressure measurement is also provided with a third sensing layer. A pair of SlideWide sensors (http://infusionsystems.com) are stuck to each other at right angles.

Illuminated button array music controllers have a long history. I was fortunate to meet the late great, Salvatore Martirano who pioneered the construction of large button array music synthesizers.

This example uses the recommended OSC SLIP wrapping for OSC serial messages. Attached is an example Max/MSP patch to display the OSC messages which represent the pin states, temperature and power supply voltages. You may need slipOSC from the CNMAT downloads page to unwrap the USB serial OSC. This is a simple introduction to building OSC messages. Yotam Mann built a complete library for Arduino that does the full OSC encoding available on github CNMAT.

/*
 * OSCuino Rough
 * Copyright 2009 Adrian Freed. All Rights Reserved
 * Read and send the state of the Arduino pins to a host
 * using the recommended Open Sound Control (OSC)  serial wrapping: slip
 *
 * version 0.95
   tested on teensy 2.0, teensy++ 1.0, lilypad, basic 168 Arduino
   lilypad.
   The Arduino Mega works if you build with the latest release
   candidate Arduino.
 *
 */
#include <avr/pgmspace.h>

// The following OSC API is temporary. Although it generates valid OSC packets
// it does not use OSC best practices or provide complete OSC features
// In particular there are no time tags (no standard clock on Arduino)
// or bundles and this api only provides for vectors of the same OSC type
// these issues will be addressed in a C++ library

const byte eot = 0300;
const byte slipesc = 0333;
const byte slipescend = 0334;
const byte slipescesc = 0335;
void oscoutbyte(byte b)
{
  if(b==eot){ 
    Serial.print(slipesc);
    Serial.print(slipescend); 
  }
  else if(b==slipesc) {  
    Serial.print(slipesc);
    Serial.print(slipescesc); 
  }
  else  Serial.print(b, BYTE);

}
void oscout10b(unsigned int b)
{
  Serial.print(0, BYTE);
  Serial.print(0, BYTE);

  oscoutbyte((b>>2));
  oscoutbyte((b<<6));
}
void oscoutword( int b)
{
  Serial.print(0, BYTE);
  Serial.print(0, BYTE);
  // Serial.print(2);
  oscoutbyte((b>>8));
  oscoutbyte((b>>0));

}
void oscoutlong(unsigned long b)
{
  oscoutbyte((b>>24));
  oscoutbyte((b>>16));
  oscoutbyte((b>>8));
  oscoutbyte((b>>0));

}
void oscoutfloat(float f)
{
  union
  {
    float f;
    unsigned long l;
  } 
  x;
  x.f = f;
  oscoutlong(x.l);
}
void sendOSCempty(char *name, char *s)
{
  Serial.print(eot,BYTE);
  Serial.print(name);

  int n =0;
  while( *name++)
    ++n;
  n %= 4;
  n = 4-n;
  //Serial.print(n);
  while(n--)
    Serial.print(0,BYTE);
  Serial.print(",");
  n = 1;
  while(*s)
    Serial.print(*s++), ++n;

  n %= 4;
  n = 4-n;
  //Serial.print(n);
  while(n--)
    Serial.print(0,BYTE);

  Serial.print(eot,BYTE);
}    


void sendOSCints(char *name,  int *integers, int length)
{
  Serial.print(eot,BYTE);
  Serial.print(name);

  int n =0;
  while( *name++)
    ++n;
  n %= 4;
  n = 4-n;
  //Serial.print(n);
  while(n--)
    Serial.print(0,BYTE);
  Serial.print(",");
  for(int i=0;i<length;++i)
  {
    Serial.print("i");
  }
  n = (length+1 )%4;
  n = 4-n;
  //Serial.print(n);
  while(n--)
    Serial.print(0,BYTE);

  for(int i=0;i<length;++i)

    oscoutword(integers[i]);
  Serial.print(eot,BYTE);

} 
void sendOSCfloats(char *name,  float *floats, int length)
{
    sendOSCthings( name, 'f', (uint32_t *) floats, length);
}

void sendOSCthings(char *name, char type, uint32_t *data, int length)
{
  Serial.print(eot,BYTE);
  Serial.print(name);

  int n =0;
  while( *name++)
    ++n;
  n %= 4;
  n = 4-n;
  //Serial.print(n);
  while(n--)
    Serial.print(0,BYTE);
  Serial.print(",");
  for(int i=0;i<length;++i)
  {
    Serial.print(type);
  }
  n = (length+1 )%4;
  n = 4-n;
  //Serial.print(n);
  while(n--)
    Serial.print(0,BYTE);

  for(int i=0;i<length;++i)
    oscoutlong(data[i]);
  Serial.print(eot,BYTE);
}    
 static inline  void sendOSClongs(char *name,  long *longs, int length)
{
     sendOSCthings(name,'i', (uint32_t *)longs,  length);
}
void sendOSCbits(char *name, boolean *bits, int length)
{
  Serial.print(eot,BYTE);
  Serial.print(name);

  int n =0;
  while( *name++)
    ++n;
  n %= 4;
  n = 4-n;
  //Serial.print(n);
  while(n--)
    Serial.print(0,BYTE);
  Serial.print(",");
  n = 1;
  for(int i=0;i<length;++i)
    Serial.print(bits[i]?'T':'F'),++n;
 
  n %= 4;
  n = 4-n;
  //Serial.print(n);
  while(n--)
    Serial.print(0,BYTE);

  Serial.print(eot,BYTE);
}    

static PROGMEM float floattable[1024] = {
0.000000, 0.000978, 0.001955, 0.002933, 0.003910, 0.004888, 0.005865, 0.006843, 0.007820, 0.008798, 0.009775, 
0.010753, 0.011730, 0.012708, 0.013685, 0.014663, 0.015640, 0.016618, 0.017595, 0.018573, 0.019550, 
0.020528, 0.021505, 0.022483, 0.023460, 0.024438, 0.025415, 0.026393, 0.027370, 0.028348, 0.029326, 
0.030303, 0.031281, 0.032258, 0.033236, 0.034213, 0.035191, 0.036168, 0.037146, 0.038123, 0.039101, 
0.040078, 0.041056, 0.042033, 0.043011, 0.043988, 0.044966, 0.045943, 0.046921, 0.047898, 0.048876, 
0.049853, 0.050831, 0.051808, 0.052786, 0.053763, 0.054741, 0.055718, 0.056696, 0.057674, 0.058651, 
0.059629, 0.060606, 0.061584, 0.062561, 0.063539, 0.064516, 0.065494, 0.066471, 0.067449, 0.068426, 
0.069404, 0.070381, 0.071359, 0.072336, 0.073314, 0.074291, 0.075269, 0.076246, 0.077224, 0.078201, 
0.079179, 0.080156, 0.081134, 0.082111, 0.083089, 0.084066, 0.085044, 0.086022, 0.086999, 0.087977, 
0.088954, 0.089932, 0.090909, 0.091887, 0.092864, 0.093842, 0.094819, 0.095797, 0.096774, 0.097752, 
0.098729, 0.099707, 0.100684, 0.101662, 0.102639, 0.103617, 0.104594, 0.105572, 0.106549, 0.107527, 
0.108504, 0.109482, 0.110459, 0.111437, 0.112414, 0.113392, 0.114370, 0.115347, 0.116325, 0.117302, 
0.118280, 0.119257, 0.120235, 0.121212, 0.122190, 0.123167, 0.124145, 0.125122, 0.126100, 0.127077, 
0.128055, 0.129032, 0.130010, 0.130987, 0.131965, 0.132942, 0.133920, 0.134897, 0.135875, 0.136852, 
0.137830, 0.138807, 0.139785, 0.140762, 0.141740, 0.142717, 0.143695, 0.144673, 0.145650, 0.146628, 
0.147605, 0.148583, 0.149560, 0.150538, 0.151515, 0.152493, 0.153470, 0.154448, 0.155425, 0.156403, 
0.157380, 0.158358, 0.159335, 0.160313, 0.161290, 0.162268, 0.163245, 0.164223, 0.165200, 0.166178, 
0.167155, 0.168133, 0.169110, 0.170088, 0.171065, 0.172043, 0.173021, 0.173998, 0.174976, 0.175953, 
0.176931, 0.177908, 0.178886, 0.179863, 0.180841, 0.181818, 0.182796, 0.183773, 0.184751, 0.185728, 
0.186706, 0.187683, 0.188661, 0.189638, 0.190616, 0.191593, 0.192571, 0.193548, 0.194526, 0.195503, 
0.196481, 0.197458, 0.198436, 0.199413, 0.200391, 0.201369, 0.202346, 0.203324, 0.204301, 0.205279, 
0.206256, 0.207234, 0.208211, 0.209189, 0.210166, 0.211144, 0.212121, 0.213099, 0.214076, 0.215054, 
0.216031, 0.217009, 0.217986, 0.218964, 0.219941, 0.220919, 0.221896, 0.222874, 0.223851, 0.224829, 
0.225806, 0.226784, 0.227761, 0.228739, 0.229717, 0.230694, 0.231672, 0.232649, 0.233627, 0.234604, 
0.235582, 0.236559, 0.237537, 0.238514, 0.239492, 0.240469, 0.241447, 0.242424, 0.243402, 0.244379, 
0.245357, 0.246334, 0.247312, 0.248289, 0.249267, 0.250244, 0.251222, 0.252199, 0.253177, 0.254154, 
0.255132, 0.256109, 0.257087, 0.258065, 0.259042, 0.260020, 0.260997, 0.261975, 0.262952, 0.263930, 
0.264907, 0.265885, 0.266862, 0.267840, 0.268817, 0.269795, 0.270772, 0.271750, 0.272727, 0.273705, 
0.274682, 0.275660, 0.276637, 0.277615, 0.278592, 0.279570, 0.280547, 0.281525, 0.282502, 0.283480, 
0.284457, 0.285435, 0.286413, 0.287390, 0.288368, 0.289345, 0.290323, 0.291300, 0.292278, 0.293255, 
0.294233, 0.295210, 0.296188, 0.297165, 0.298143, 0.299120, 0.300098, 0.301075, 0.302053, 0.303030, 
0.304008, 0.304985, 0.305963, 0.306940, 0.307918, 0.308895, 0.309873, 0.310850, 0.311828, 0.312805, 
0.313783, 0.314761, 0.315738, 0.316716, 0.317693, 0.318671, 0.319648, 0.320626, 0.321603, 0.322581, 
0.323558, 0.324536, 0.325513, 0.326491, 0.327468, 0.328446, 0.329423, 0.330401, 0.331378, 0.332356, 
0.333333, 0.334311, 0.335288, 0.336266, 0.337243, 0.338221, 0.339198, 0.340176, 0.341153, 0.342131, 
0.343109, 0.344086, 0.345064, 0.346041, 0.347019, 0.347996, 0.348974, 0.349951, 0.350929, 0.351906, 
0.352884, 0.353861, 0.354839, 0.355816, 0.356794, 0.357771, 0.358749, 0.359726, 0.360704, 0.361681, 
0.362659, 0.363636, 0.364614, 0.365591, 0.366569, 0.367546, 0.368524, 0.369501, 0.370479, 0.371457, 
0.372434, 0.373412, 0.374389, 0.375367, 0.376344, 0.377322, 0.378299, 0.379277, 0.380254, 0.381232, 
0.382209, 0.383187, 0.384164, 0.385142, 0.386119, 0.387097, 0.388074, 0.389052, 0.390029, 0.391007, 
0.391984, 0.392962, 0.393939, 0.394917, 0.395894, 0.396872, 0.397849, 0.398827, 0.399804, 0.400782, 
0.401760, 0.402737, 0.403715, 0.404692, 0.405670, 0.406647, 0.407625, 0.408602, 0.409580, 0.410557, 
0.411535, 0.412512, 0.413490, 0.414467, 0.415445, 0.416422, 0.417400, 0.418377, 0.419355, 0.420332, 
0.421310, 0.422287, 0.423265, 0.424242, 0.425220, 0.426197, 0.427175, 0.428152, 0.429130, 0.430108, 
0.431085, 0.432063, 0.433040, 0.434018, 0.434995, 0.435973, 0.436950, 0.437928, 0.438905, 0.439883, 
0.440860, 0.441838, 0.442815, 0.443793, 0.444770, 0.445748, 0.446725, 0.447703, 0.448680, 0.449658, 
0.450635, 0.451613, 0.452590, 0.453568, 0.454545, 0.455523, 0.456500, 0.457478, 0.458456, 0.459433, 
0.460411, 0.461388, 0.462366, 0.463343, 0.464321, 0.465298, 0.466276, 0.467253, 0.468231, 0.469208, 
0.470186, 0.471163, 0.472141, 0.473118, 0.474096, 0.475073, 0.476051, 0.477028, 0.478006, 0.478983, 
0.479961, 0.480938, 0.481916, 0.482893, 0.483871, 0.484848, 0.485826, 0.486804, 0.487781, 0.488759, 
0.489736, 0.490714, 0.491691, 0.492669, 0.493646, 0.494624, 0.495601, 0.496579, 0.497556, 0.498534, 
0.499511, 0.500489, 0.501466, 0.502444, 0.503421, 0.504399, 0.505376, 0.506354, 0.507331, 0.508309, 
0.509286, 0.510264, 0.511241, 0.512219, 0.513196, 0.514174, 0.515152, 0.516129, 0.517107, 0.518084, 
0.519062, 0.520039, 0.521017, 0.521994, 0.522972, 0.523949, 0.524927, 0.525904, 0.526882, 0.527859, 
0.528837, 0.529814, 0.530792, 0.531769, 0.532747, 0.533724, 0.534702, 0.535679, 0.536657, 0.537634, 
0.538612, 0.539589, 0.540567, 0.541544, 0.542522, 0.543500, 0.544477, 0.545455, 0.546432, 0.547410, 
0.548387, 0.549365, 0.550342, 0.551320, 0.552297, 0.553275, 0.554252, 0.555230, 0.556207, 0.557185, 
0.558162, 0.559140, 0.560117, 0.561095, 0.562072, 0.563050, 0.564027, 0.565005, 0.565982, 0.566960, 
0.567937, 0.568915, 0.569892, 0.570870, 0.571848, 0.572825, 0.573803, 0.574780, 0.575758, 0.576735, 
0.577713, 0.578690, 0.579668, 0.580645, 0.581623, 0.582600, 0.583578, 0.584555, 0.585533, 0.586510, 
0.587488, 0.588465, 0.589443, 0.590420, 0.591398, 0.592375, 0.593353, 0.594330, 0.595308, 0.596285, 
0.597263, 0.598240, 0.599218, 0.600196, 0.601173, 0.602151, 0.603128, 0.604106, 0.605083, 0.606061, 
0.607038, 0.608016, 0.608993, 0.609971, 0.610948, 0.611926, 0.612903, 0.613881, 0.614858, 0.615836, 
0.616813, 0.617791, 0.618768, 0.619746, 0.620723, 0.621701, 0.622678, 0.623656, 0.624633, 0.625611, 
0.626588, 0.627566, 0.628543, 0.629521, 0.630499, 0.631476, 0.632454, 0.633431, 0.634409, 0.635386, 
0.636364, 0.637341, 0.638319, 0.639296, 0.640274, 0.641251, 0.642229, 0.643206, 0.644184, 0.645161, 
0.646139, 0.647116, 0.648094, 0.649071, 0.650049, 0.651026, 0.652004, 0.652981, 0.653959, 0.654936, 
0.655914, 0.656891, 0.657869, 0.658847, 0.659824, 0.660802, 0.661779, 0.662757, 0.663734, 0.664712, 
0.665689, 0.666667, 0.667644, 0.668622, 0.669599, 0.670577, 0.671554, 0.672532, 0.673509, 0.674487, 
0.675464, 0.676442, 0.677419, 0.678397, 0.679374, 0.680352, 0.681329, 0.682307, 0.683284, 0.684262, 
0.685239, 0.686217, 0.687195, 0.688172, 0.689150, 0.690127, 0.691105, 0.692082, 0.693060, 0.694037, 
0.695015, 0.695992, 0.696970, 0.697947, 0.698925, 0.699902, 0.700880, 0.701857, 0.702835, 0.703812, 
0.704790, 0.705767, 0.706745, 0.707722, 0.708700, 0.709677, 0.710655, 0.711632, 0.712610, 0.713587, 
0.714565, 0.715543, 0.716520, 0.717498, 0.718475, 0.719453, 0.720430, 0.721408, 0.722385, 0.723363, 
0.724340, 0.725318, 0.726295, 0.727273, 0.728250, 0.729228, 0.730205, 0.731183, 0.732160, 0.733138, 
0.734115, 0.735093, 0.736070, 0.737048, 0.738025, 0.739003, 0.739980, 0.740958, 0.741935, 0.742913, 
0.743891, 0.744868, 0.745846, 0.746823, 0.747801, 0.748778, 0.749756, 0.750733, 0.751711, 0.752688, 
0.753666, 0.754643, 0.755621, 0.756598, 0.757576, 0.758553, 0.759531, 0.760508, 0.761486, 0.762463, 
0.763441, 0.764418, 0.765396, 0.766373, 0.767351, 0.768328, 0.769306, 0.770283, 0.771261, 0.772239, 
0.773216, 0.774194, 0.775171, 0.776149, 0.777126, 0.778104, 0.779081, 0.780059, 0.781036, 0.782014, 
0.782991, 0.783969, 0.784946, 0.785924, 0.786901, 0.787879, 0.788856, 0.789834, 0.790811, 0.791789, 
0.792766, 0.793744, 0.794721, 0.795699, 0.796676, 0.797654, 0.798631, 0.799609, 0.800587, 0.801564, 
0.802542, 0.803519, 0.804497, 0.805474, 0.806452, 0.807429, 0.808407, 0.809384, 0.810362, 0.811339, 
0.812317, 0.813294, 0.814272, 0.815249, 0.816227, 0.817204, 0.818182, 0.819159, 0.820137, 0.821114, 
0.822092, 0.823069, 0.824047, 0.825024, 0.826002, 0.826979, 0.827957, 0.828935, 0.829912, 0.830890, 
0.831867, 0.832845, 0.833822, 0.834800, 0.835777, 0.836755, 0.837732, 0.838710, 0.839687, 0.840665, 
0.841642, 0.842620, 0.843597, 0.844575, 0.845552, 0.846530, 0.847507, 0.848485, 0.849462, 0.850440, 
0.851417, 0.852395, 0.853372, 0.854350, 0.855327, 0.856305, 0.857283, 0.858260, 0.859238, 0.860215, 
0.861193, 0.862170, 0.863148, 0.864125, 0.865103, 0.866080, 0.867058, 0.868035, 0.869013, 0.869990, 
0.870968, 0.871945, 0.872923, 0.873900, 0.874878, 0.875855, 0.876833, 0.877810, 0.878788, 0.879765, 
0.880743, 0.881720, 0.882698, 0.883675, 0.884653, 0.885630, 0.886608, 0.887586, 0.888563, 0.889541, 
0.890518, 0.891496, 0.892473, 0.893451, 0.894428, 0.895406, 0.896383, 0.897361, 0.898338, 0.899316, 
0.900293, 0.901271, 0.902248, 0.903226, 0.904203, 0.905181, 0.906158, 0.907136, 0.908113, 0.909091, 
0.910068, 0.911046, 0.912023, 0.913001, 0.913978, 0.914956, 0.915934, 0.916911, 0.917889, 0.918866, 
0.919844, 0.920821, 0.921799, 0.922776, 0.923754, 0.924731, 0.925709, 0.926686, 0.927664, 0.928641, 
0.929619, 0.930596, 0.931574, 0.932551, 0.933529, 0.934506, 0.935484, 0.936461, 0.937439, 0.938416, 
0.939394, 0.940371, 0.941349, 0.942326, 0.943304, 0.944282, 0.945259, 0.946237, 0.947214, 0.948192, 
0.949169, 0.950147, 0.951124, 0.952102, 0.953079, 0.954057, 0.955034, 0.956012, 0.956989, 0.957967, 
0.958944, 0.959922, 0.960899, 0.961877, 0.962854, 0.963832, 0.964809, 0.965787, 0.966764, 0.967742, 
0.968719, 0.969697, 0.970674, 0.971652, 0.972630, 0.973607, 0.974585, 0.975562, 0.976540, 0.977517, 
0.978495, 0.979472, 0.980450, 0.981427, 0.982405, 0.983382, 0.984360, 0.985337, 0.986315, 0.987292, 
0.988270, 0.989247, 0.990225, 0.991202, 0.992180, 0.993157, 0.994135, 0.995112, 0.996090, 0.997067, 
0.998045, 0.999022, 1.000000, 
};


static inline float floatfrom10bitint(int n)
{
  return pgm_read_float(floattable+constrain(n,0,1023));
}

inline void digitalPullup(byte pin, boolean b) { 
  pinMode(pin, INPUT); 
  digitalWrite(pin, b?HIGH:LOW); 
}

#if defined(__AVR_ATmega1280__)
#define MAXADC 16
const int numberOfArduinoDigitalPins=54;
inline void analogPullup(byte pin, boolean b) { 
  digitalPullup(pin+54,b); 
}
inline void analogOutWrite(byte pin, byte b) {
  pinMode(pin+54, OUTPUT);  
  digitalWrite(pin+54,b);
}

#else
// teensy++
#if defined(__AVR_AT90USB646__) || defined(__AVR_AT90USB1286__)

#define MAXADC 8
const int numberOfArduinoDigitalPins=38;
inline void analogPullup(byte pin, boolean b) { 
   pinMode(38+pin,b?INPUT_PULLUP: INPUT); 
}
inline void analogOutWrite(byte pin, byte b) {
  pinMode(38+pin, OUTPUT);  // change directions of an analog pin
  digitalWrite(38+pin,b); 
}
#else
//AT90USB1286 teensy++
#if defined(__AVR_ATmega32U4__)
//teensy 2.0
#define MAXADC 12
const int numberOfArduinoDigitalPins=11; // actually the teensy 2.0 has two more non contiguously addressed (22 and 23)
inline void analogPullup(byte pin, boolean b) { 
 if(pin==11)
    pin = -1; // ouch read the diagram carefully! http://www.pjrc.com/teensy/pinout.html
   pinMode(21-pin,b?INPUT_PULLUP: INPUT); 
}
typedef enum {
  endOfpinlist=-1, a0=14,a1,a2,a3,a4,a5,a6,a7,a8,a9,a10,a11,a12,a13,a14,a15 } 
pinnames;
inline void analogOutWrite(byte pin, byte b) {
  if(pin==11)
    pin = -1; // ouch
  pinMode(21-pin, OUTPUT);  // change directions of an analog pin
  digitalWrite(21-pin,b); 
}
#else
//6 or 8 depending
#define MAXADC 8
const int numberOfArduinoDigitalPins=13;
inline void analogPullup(byte pin, boolean b) { 
  digitalPullup(pin+14,b?HIGH:LOW); 
}

inline void analogOutWrite(byte pin, byte b) {
 
  pinMode(pin+14, OUTPUT);  // change directions of an analog pin
  digitalWrite(pin+14,b); 
}
#endif
#endif
#endif
const boolean debugging = false; // send the processed data over serial console for debugging instead of OSC
const boolean fulldebugging = false; // turn this on to get all the raw data in a form you can read on the serial console


void setup() {
  Serial.begin(debugging?9600:57600);
}
const int dtime=0;
#define BANDGAPREF 14   // special indicator that we want to measure the bandgap

void loop(){
 // analog inputs
  int adcs[MAXADC];
  float fbuf[MAXADC];
  int i;
  
  for(i=0;i<MAXADC;++i)
    analogPullup(i,false);
  for(i=0;i<MAXADC;++i)
    adcs[i] = analogRead(i); 
  for(i=0;i<MAXADC;++i)
    fbuf[i] = floatfrom10bitint(adcs[i]);
  sendOSCfloats("/analog", fbuf, MAXADC);  
 
  for(i=0;i<MAXADC;++i)
    analogPullup(i,true);
  for(i=0;i<MAXADC;++i)
    adcs[i] = analogRead(i); 
  for(i=0;i<MAXADC;++i)
    fbuf[i] = floatfrom10bitint(adcs[i]);
  sendOSCfloats("/up/analog", fbuf, MAXADC);  

   // temperature
  // power supply voltage
  // (clock rate)
  //digital pins
  boolean arduinodigitalpins[numberOfArduinoDigitalPins];
  for(i=0;i<numberOfArduinoDigitalPins;++i)
    digitalPullup(i,false);
  for(i=0;i<numberOfArduinoDigitalPins;++i)
    arduinodigitalpins[i] = digitalRead(i);
 sendOSCbits("/digital", arduinodigitalpins, numberOfArduinoDigitalPins);
  
  for(i=0;i<numberOfArduinoDigitalPins;++i)
    digitalPullup(i,true);
  for(i=0;i<numberOfArduinoDigitalPins;++i)
    arduinodigitalpins[i] = digitalRead(i);
 sendOSCbits("/up/digital", arduinodigitalpins, numberOfArduinoDigitalPins);
 
 #if defined(__AVR_ATmega32U4__)
Serial.send_now(); 
#endif
 #if !defined(__AVR_ATmega8__)

// temperature and power supply measurement on some Arduinos 
    // powersupply
    int result;
  // Read 1.1V reference against AVcc
#if defined(__AVR_ATmega32U4__)
  ADMUX = 0x40 | _BV(MUX4)| _BV(MUX3) | _BV(MUX2) | _BV(MUX1);
  ADCSRB =  0;
  //  ADCSRB = DEFAULT_ADCSRB | (1<<MUX5);
#elif  defined(__AVR_AT90USB646__) || defined(__AVR_AT90USB1286__)    || defined(__AVR_ATmega1280__) 
  ADMUX = 0x40| _BV(MUX4) | _BV(MUX3) | _BV(MUX2) | _BV(MUX1) ;
    ADCSRB =  0;
#else
  ADMUX = _BV(REFS0) | _BV(MUX3) | _BV(MUX2) | _BV(MUX1);
#endif
  delayMicroseconds(300); // wait for Vref to settle
  ADCSRA |= _BV(ADSC); // Convert
  while (bit_is_set(ADCSRA,ADSC));
   result = ADCL;
  result |= ADCH<<8;
#endif
//    analogReference(EXTERNAL);

  float supplyvoltage = 1.1264 *1023 / result;
  sendOSCfloats("/power", &supplyvoltage, 1);


#if defined(__AVR_ATmega32U4__) ||    (!defined(__AVR_ATmega1280__) && !defined(__AVR_ATmega8__) && !defined(__AVR_AT90USB646__) && !defined(__AVR_AT90USB1286__))
 // temperature

#if defined(__AVR_ATmega32U4__)
  ADMUX =  _BV(REFS1) | _BV(REFS0) | _BV(MUX2) | _BV(MUX1) | _BV(MUX0);
   ADCSRB =  _BV(MUX5);
#else
  ADMUX = _BV(REFS1) | _BV(REFS0) | _BV(MUX3);
#endif
  

  delayMicroseconds(200); // wait for Vref to settle
  ADCSRA |= _BV(ADSC); // Convert
  while (bit_is_set(ADCSRA,ADSC));
  result = ADCL;
  result |= ADCH<<8;

   float temp= result/1023.0;
     sendOSCfloats("/temperature", &temp, 1);
   analogReference(DEFAULT);
 #endif
 
  long l=micros();
  sendOSClongs("/microseconds",&l,1);
#if defined(__AVR_ATmega32U4__)
Serial.send_now(); 
#endif
}

Experimental surface sensing for fingerstyle players

I don't use the stock "official" Arduino boards for my work. The $18 teensy 2.0 is smaller than any of the stock Arduinos, has more A/D pins than any of them except the Mega, has more memory, more PWM pins, full speed USB serial support and has a more accurate crystal cock instead of a resonator. You can buy them from the designer ($18$16) or from Lady Ada ($20). Sketch loading and restart is much faster because of the high speed USB port.

The FTDI drivers aren't necessary with the Teensy and you can add the Teensyduino overlay to run your Arduino sketches.

The overlay has several high performance features the Arduino core group haven't got round to yet: the A/D is run in high speed mode and the serial port implementation is efficiently interrupt driven on input and output.

So what is the catch? Some hardware improvements I suggest: get the silkscreen right for Arduino nomenclature, move the led from an analog input to a digital pin and build it with the 3.3v regulator on board and a switch (like the seeeduino boards) ditto for the teensy++. I would pay the extra few dollars for this.

If I really have to use the original Arduino form factor (to leverage a useful shield) I use the seeeduino or olimexino. They are compatible, comparably priced and have some handy extra switches, power supply features and break out the 2 extra A/D pins often omitted on other boards.

An audio oscillator using digital ICs, Freed, A. , Electronics Australia, 01/1978, Volume 39, Number 10, p.53-4, (1978)