diff options
| -rw-r--r-- | accel.c | 109 | ||||
| -rw-r--r-- | accel.h | 4 | ||||
| -rw-r--r-- | main.c | 6 |
3 files changed, 118 insertions, 1 deletions
@@ -17,8 +17,33 @@ #define LIS302DL_CTRLREG1 0x20 #define LIS302DL_UNUSED1 0x28 +/* value for 1g with +-2g max; measured */ +#define ACCEL_1G_POS (55) +#define ACCEL_1G_NEG (-55) +/* offset for horizon detection */ +#define ACCEL_1G_OFF (5) +/* shake detection values; 2g for +-2g max */ +#define ACCEL_SHAKE_POS (INT8_MAX) +#define ACCEL_SHAKE_NEG (INT8_MIN) +/* 250ms for 100Hz data rate */ +#define ACCEL_SHAKE_TIMEOUT (25) + /* 0, 2 and 4 are zero, as they contain the dummy register’s content */ static volatile int8_t val[6] = {0, 0, 0, 0, 0, 0}; +/* number of times shaken (i.e. peak level measured) */ +static uint8_t shakeCount = 0; +/* if max in one direction direction has been detected give it some time to + * wait for max in the other direction */ +static uint8_t shakeTimeout = 0; +/* sign of last shake peak */ +static enum {SHAKE_NONE, SHAKE_POS, SHAKE_NEG} shakeSign = SHAKE_NONE; +/* horizon position */ +/* current */ +static horizon horizonSign = HORIZON_NONE; +/* how long has sign been stable? */ +static uint8_t horizonStable = 0; +/* previous measurement */ +static horizon horizonPrevSign = HORIZON_NONE; /* currently reading from i2c */ static bool reading = false; @@ -55,9 +80,85 @@ void accelStart () { printf ("final twi status was %i\n", twr.status); } +/* register shake gesture + * + * “shake” means a peak in one direction followed by another one in the other + * direction. called for every data set pulled. + */ +static void accelProcessShake () { + const int8_t zval = val[5]; + /* detect shake if: + * a) horizon is positive and accel z value is >= ACCEL_SHAKE_POS + * b) horizon is negative and accel z value is >= ACCEL_SHAKE_POS offset by + * the value for 1g (negative) + * (same for negative horizon) + */ + if (((zval >= ACCEL_SHAKE_POS && + horizonSign == HORIZON_POS) || + (zval >= (ACCEL_SHAKE_POS + ACCEL_1G_NEG) && + horizonSign == HORIZON_NEG)) && + shakeSign != SHAKE_POS) { + /* if we did not time out (i.e. max in other direction has been + * detected) register shake */ + if (shakeTimeout > 0) { + ++shakeCount; + /* correctly detect double/triple/… shakes; setting this to + * ACCEL_SHAKE_TIMEOUT yields wrong results */ + shakeTimeout = 0; + } else { + shakeTimeout = ACCEL_SHAKE_TIMEOUT; + } + shakeSign = SHAKE_POS; + } else if (((zval <= ACCEL_SHAKE_NEG && + horizonSign == HORIZON_NEG) || + (zval <= (ACCEL_SHAKE_NEG + ACCEL_1G_POS) && + horizonSign == HORIZON_POS)) && + shakeSign != SHAKE_NEG) { + if (shakeTimeout > 0) { + ++shakeCount; + shakeTimeout = 0; + } else { + shakeTimeout = ACCEL_SHAKE_TIMEOUT; + } + shakeSign = SHAKE_NEG; + } else { + if (shakeTimeout > 0) { + --shakeTimeout; + } + } +} + +/* register horizon change + * + * i.e. have we been turned upside down? + */ +static void accelProcessHorizon () { + const int8_t zval = val[5]; + /* measuring approximately 1g */ + if (zval > (ACCEL_1G_POS - ACCEL_1G_OFF) && + zval < (ACCEL_1G_POS + ACCEL_1G_OFF) && + horizonPrevSign == HORIZON_POS && horizonSign != HORIZON_POS) { + ++horizonStable; + } else if (zval < (ACCEL_1G_NEG + ACCEL_1G_OFF) + && zval > (ACCEL_1G_NEG - ACCEL_1G_OFF) && + horizonPrevSign == HORIZON_NEG && horizonSign != HORIZON_NEG) { + ++horizonStable; + } else { + horizonStable = 0; + } + /* make sure its not just shaking */ + if (horizonStable > 5) { + horizonSign = horizonPrevSign; + horizonStable = 0; + } + horizonPrevSign = zval >= 0 ? HORIZON_POS : HORIZON_NEG; +} + bool accelProcess () { if (reading) { if (twr.status == TWST_OK) { + accelProcessHorizon (); + accelProcessShake (); /* new data transfered */ reading = false; return true; @@ -85,3 +186,11 @@ volatile const int8_t *accelGet () { return val; } +const uint8_t accelGetShakeCount () { + return shakeCount; +} + +const horizon accelGetHorizon () { + return horizonSign; +} + @@ -4,10 +4,14 @@ #include <stdbool.h> #include <stdint.h> +typedef enum {HORIZON_NONE, HORIZON_POS, HORIZON_NEG} horizon; + void accelInit (); void accelStart (); bool accelProcess (); volatile const int8_t *accelGet (); +const uint8_t accelGetShakeCount (); +const horizon accelGetHorizon (); #endif /* ACCEL_H */ @@ -60,9 +60,11 @@ int main () { gyroStart (); accelStart (); +#if 0 speakerStart (); _delay_ms (200); speakerStop (); +#endif timerStart (); bool checkGyro = false; @@ -81,7 +83,9 @@ int main () { sleep_cpu (); sleep_disable (); } - printf ("ticks=%i\n", gyroGetZTicks ()); + + printf ("t=%i, h=%i, s=%i\n", gyroGetZTicks (), accelGetHorizon (), + accelGetShakeCount ()); #if 0 volatile const int32_t *gyroval = gyroGetAccum (); volatile const int16_t *gyroraw = gyroGetRaw (); |