#include #include #include #include #include #define G 28 /* 1 Earth gravity in accelerometer units */ #define MID 512 /* accelerometer middle value */ #define S 1000 /* sample rate (samples/s) */ #define F 2 /* rotational speed in Hz */ #define R 0.46 /* radius of accelerometer orbit */ #define H (G/2) /* hysteresis, in accelerometer units */ /* noise pattern: frequency, amplitude pairs */ static struct noise { int f; /* frequency (in samples) */ int a; /* amplitude (in accelerometer units) */ } noise[] = { { 1, G/3 }, /* general noise */ { S/F/10, 5*G }, /* hits caused by the chain "jumping" */ { 0, } }; static uint16_t sample(double t) { int fz = R*4*M_PI*M_PI*F*F/9.81*G; int fg = cos(2*M_PI*F*t)*G; int f = fz+fg; const struct noise *n; for (n = noise; n->f; n++) if (!(random() % n->f)) f += random() % (2*n->a) - n->a; return f+MID; } #define E_SHIFT 3 /* ~ 0.1 */ #define M_SHIFT 10 /* ~ 1/S */ static void process(unsigned v) { static uint16_t e = MID << E_SHIFT; static uint32_t m = MID << M_SHIFT; static bool up = 0; int d; e = v+(e-(e >> E_SHIFT)); m = v+(m-(m >> M_SHIFT)); d = (e >> E_SHIFT)-(m >> M_SHIFT); if (up) { if (d < -H) up = 0; } else { if (d > H) up = 1; } printf("%d %d %d %d %d\n", v, e >> E_SHIFT, m >> M_SHIFT, d, up); } static void usage(const char *name) { fprintf(stderr, "usage: %s [seconds]\n", name); exit(1); } int main(int argc, char **argv) { double t; char *end; int i; unsigned v; switch (argc) { case 1: while (scanf("%u", &v) == 1) process(v); break; case 2: t = strtod(argv[1], &end); if (*end) usage(*argv); for (i = 0; i != t*S; i++) { v = sample((double) i/S); process(v); } break; default: usage(*argv); } return 0; }