diff --git a/fw/antorcha.c b/fw/antorcha.c
index ac8c3fd..5b7d802 100644
--- a/fw/antorcha.c
+++ b/fw/antorcha.c
@@ -20,16 +20,84 @@
 #include "accel.h"
 #include "image.h"
 
+#include <avr/interrupt.h>
+#include "io.h"
+
 
 static struct sweep sweep = {
-	.wait_ticks	=	100000,	/* 100 ms */
-	.pixel_ticks	=	  5000,	/*   5 ms */
+	.wait_ticks	=	 60000,	/*  60 ms */
+	.pixel_ticks	=	  1000,	/*   1 ms */
 	.left		=	     0,
-	.right		= MAX_LINES-1,
+	.right		=	    79,
 	.forward 	=	     1,
 };
 
 
+static volatile enum sync_state {
+	IDLE,
+	LEFT_DECEL,
+	LEFT_ACCEL,
+	FWD_START_SWEEP,
+	FWD_SWEEP,
+} state = IDLE;
+
+
+#define	LEFT_DECEL_THRESH	850
+#define	LEFT_REVERSE_THRESH	900
+#define	LEFT_ACCEL_THRESH	850
+#define	RIGHT_DECEL_THRESH	200
+
+
+static void sync_sweep(bool x, uint16_t v)
+{
+	static uint32_t t;
+
+	if (!x)
+		return;
+	switch (state) {
+default:
+	case IDLE:
+		if (v < LEFT_DECEL_THRESH)
+			break;
+		state = LEFT_DECEL;
+		t = uptime_irq();
+		break;
+	case LEFT_DECEL:
+		if (v < LEFT_DECEL_THRESH) {
+			t = uptime_irq();
+			break;
+		}
+#if 0
+		if (v > LEFT_REVERSE_THRESH)
+			state = LEFT_ACCEL;
+		break;
+	case LEFT_ACCEL:
+		if (v > LEFT_ACCEL_THRESH)
+			break;
+#else
+		if (v < LEFT_REVERSE_THRESH)
+			break;
+#endif
+		if (sweeping) { /* we're confused */
+			state = IDLE;
+			break;
+		}
+		state = FWD_START_SWEEP;
+		/* t = t1-(t1+t0)/2 = (t1-t0)/2 */
+		t = (uptime_irq()-t) >> 1;
+//		sweep.wait_ticks = kkkkkk
+		break;	
+	case FWD_START_SWEEP:
+		break;
+	case FWD_SWEEP:
+		if (v > RIGHT_DECEL_THRESH)
+			break;
+		state = IDLE;
+		break;
+	}
+}
+
+
 static const struct handler *protos[] = {
 	&image_handler,
 	&reset_handler,
@@ -49,13 +117,19 @@ int main(void)
 	 */
 
 	sweep_init();
+	sample = sync_sweep;
 	accel_start();
+sei();
 
 	while (1) {
 		got = rf_recv(buf, sizeof(buf));
 		if (got > 2)
 			dispatch(buf, got-2, protos);
-		if (!sweeping)
+#if 1
+		if (state == FWD_START_SWEEP && !sweeping) {
+			state = FWD_SWEEP;
 			sweep_image(&sweep);
+		}
+#endif
 	}
 }