Move moo-detection into accel driver

Slight refactorization: The decision, whether a moo should happen, is
moved to the driver-specific code (because it knows best what kind of
device to expect). A member “state” is added to the accel struct which
can be used to implement a state machine inside the driver (as was done
before with pos).

2 files changed, 55 insertions, 39 deletions

diff --git a/src/accelerometers.c b/src/accelerometers.c
index deaeff1..08f141d 100644
--- a/src/accelerometers.c
+++ b/src/accelerometers.c
@@ -65,6 +65,7 @@ AccelHandle *accelerometer_open() {
 	accel->lx = 0;
 	accel->ly = 0;
 	accel->lz = 0;
+	accel->state = 0;
 	accel->type = ACCEL_UNKNOWN;
 	
 	/* Determine accelerometer type */
@@ -89,7 +90,7 @@ AccelHandle *accelerometer_open() {
 
 }
 
-void accelerometer_update_hdaps(AccelHandle *accel) {
+int accelerometer_moo_hdaps(AccelHandle *accel) {
 
 	struct input_event ev;
 	size_t rval;
@@ -97,38 +98,50 @@ void accelerometer_update_hdaps(AccelHandle *accel) {
 	rval = read(accel->fd, &ev, sizeof(ev));
 	if ( rval != sizeof(ev) ) {
 		fprintf(stderr, "Couldn't read accelerometer data");
-		return;
+		return 0;
 	}
 	if (ev.type == EV_ABS && ev.code == REL_Y) {
-		// This is the result of some experimentation
-		accel->y = -600 + abs(ev.value) * 12;
+		if (accel->state == 0 && abs(ev.value)>100) {
+			// Laptop tilted far enough
+			accel->state=1;
+			return 0;
+		}
+
+		if (accel->state == 1 && abs(ev.value)<70) {
+			// Laptop tilted back, play sound
+			accel->state=2;
+			return 1;
+		}
+		
+		if (accel->state == 2 && abs(ev.value)<20) {
+			// Laptop almost at center, enable another round
+			accel->state=0;
+			return 0;
+		}
 	}
 
+	return 0;
+		
+	/*
+ 	fprintf(stderr, "Event: time %ld.%06ld, type %s, code %d, value %d\n",
+		       ev.time.tv_sec, ev.time.tv_usec,
+		       ev.type == EV_REL ? "REL" : 
+                       ev.type == EV_ABS ? "ABS" : "Other" ,
+		       ev.code, ev.value);
+	*/
 }
 
-void accelerometer_update_freerunner(AccelHandle *accel) {
+int accelerometer_moo_freerunner(AccelHandle *accel) {
 
 	struct input_event ev;
 	size_t rval;
 	fd_set fds;
 	struct timeval t;
 	
-	FD_ZERO(&fds);
-	FD_SET(accel->fd, &fds);
-	t.tv_sec = 0;
-	t.tv_usec = 0;
-	select(1+accel->fd, &fds, NULL, NULL, &t);
-	
-	if ( FD_ISSET(accel->fd, &fds) ) {
-	
-		rval = read(accel->fd, &ev, sizeof(ev));
-		if ( rval != sizeof(ev) ) {
-			fprintf(stderr, "Couldn't read accelerometer data");
-			return;
-		}
-		
-	} else {
-		return;	/* No data */
+	rval = read(accel->fd, &ev, sizeof(ev));
+	if ( rval != sizeof(ev) ) {
+		fprintf(stderr, "Couldn't read accelerometer data");
+		return 0;
 	}
 	
 	if ( ev.type == EV_REL ) {
@@ -151,27 +164,35 @@ void accelerometer_update_freerunner(AccelHandle *accel) {
 		}
 	}
 
+	if ( (accel->y < -500) && (accel->state > -1000) ) {
+		accel->state = -1000;
+		return 1;
+	}
+
+	if ( (accel->y > 500) && (accel->state < 1000) ) {
+		accel->state = 1000;
+		return 1;
+	}
+
+	return 0;
 }
 
-void accelerometer_update(AccelHandle *accel) {
+int accelerometer_moo(AccelHandle *accel) {
 
 	switch ( accel->type ) {
 		case ACCEL_UNKNOWN : {
-			return;
+			return 0;
 		}
 		case ACCEL_FREERUNNER : {
-			accelerometer_update_freerunner(accel);
-			break;
+			return accelerometer_moo_freerunner(accel);
 		}
 		case ACCEL_HDAPS : {
-			accelerometer_update_hdaps(accel);
-			break;
+			return accelerometer_moo_hdaps(accel);
 		}
-		/* Add other types here. You simply need to provide the "y"
-		 * component of acceleration in milli-g in the relevant
-		 * structure. */
+		/* Add other types here. */
 	}
 
+	return 0;
 }
 
 /* The accelerometer work thread */
@@ -179,22 +200,14 @@ static void *accel_work(void *data) {
 
 	AccelHandle *accel;
 	int *finished = data;
-	int pos = 0;
 	
 	accel = accelerometer_open();
 	audio_setup();
 	
 	while ( !(*finished) ) {
 	
-		accelerometer_update(accel);
-		
-		if ( (accel->y < -500) && (pos > -1000) ) {
-			pos = -1000;
+		if (accelerometer_moo(accel))
 			audio_trigger_moo();
-		} else if ( (accel->y > 500) && (pos < 1000) ) {
-			pos = 1000;
-			audio_trigger_moo();
-		}
 		
 		usleep(25000);
 		
diff --git a/src/types.h b/src/types.h
index eae97b6..cc7a227 100644
--- a/src/types.h
+++ b/src/types.h
@@ -50,6 +50,9 @@ typedef struct {
 	int		lx;
 	int		ly;
 	int		lz;
+	
+	/* Current state (driver dependent) */
+	int		state;
 
 } AccelHandle;