From: Keith Packard <keithp@keithp.com>
Date: Mon, 14 Oct 2013 05:05:20 +0000 (-0700)
Subject: altos/micropeak: Increase boost detect to 30m
X-Git-Tag: 1.2.9.4~44
X-Git-Url: https://git.gag.com/?p=fw%2Faltos;a=commitdiff_plain;h=1bd9786802751391cca3b83ac3045029e00e39ee;ds=sidebyside

altos/micropeak: Increase boost detect to 30m

This meant increasing the data buffering as well so that we could
reliably capture the flight data back to the ground, even for slow
flights.

And, with the buffer extra large, we work backwards from the current
buffer location to find the last ground location rather than working
forwards from the first buffered location. This ensures that we don't
capture noise before boost and instead capture a nice flight curve instead.

Signed-off-by: Keith Packard <keithp@keithp.com>
---

diff --git a/src/core/ao_microflight.c b/src/core/ao_microflight.c
index 714bb90a..f680e400 100644
--- a/src/core/ao_microflight.c
+++ b/src/core/ao_microflight.c
@@ -33,7 +33,7 @@ ao_microsample(void)
 	ao_microkalman_correct();
 }
 
-#define NUM_PA_HIST	16
+#define NUM_PA_HIST	(GROUND_AVG)
 
 #define SKIP_PA_HIST(i,j)	(((i) + (j)) & (NUM_PA_HIST - 1))
 
@@ -60,11 +60,11 @@ ao_microflight(void)
 	h = 0;
 	for (;;) {
 		time += SAMPLE_SLEEP;
-		if (sample_count == 0)
+		if ((sample_count & 0x1f) == 0)
 			ao_led_on(AO_LED_REPORT);
 		ao_delay_until(time);
 		ao_microsample();
-		if (sample_count == 0)
+		if ((sample_count & 0x1f) == 0)
 			ao_led_off(AO_LED_REPORT);
 		pa_hist[h] = pa;
 		h = SKIP_PA_HIST(h,1);
@@ -85,10 +85,10 @@ ao_microflight(void)
 		}
 	}
 
-	/* Go back and find the first sample a decent interval above the ground */
+	/* Go back and find the last sample close to the ground */
 	pa_min = pa_ground - LAND_DETECT;
-	for (i = SKIP_PA_HIST(h,2); i != h; i = SKIP_PA_HIST(i,2)) {
-		if (pa_hist[i] < pa_min)
+	for (i = SKIP_PA_HIST(h,-2); i != SKIP_PA_HIST(h,2); i = SKIP_PA_HIST(i,-2)) {
+		if (pa_hist[i] >= pa_min)
 			break;
 	}
 
diff --git a/src/product/ao_micropeak.h b/src/product/ao_micropeak.h
index 3e3dec15..0cefca6f 100644
--- a/src/product/ao_micropeak.h
+++ b/src/product/ao_micropeak.h
@@ -20,12 +20,12 @@
 
 #define SAMPLE_SLEEP		AO_MS_TO_TICKS(96)
 
-/* 16 sample, or about two seconds worth */
-#define GROUND_AVG_SHIFT	4
+/* 64 sample, or about six seconds worth */
+#define GROUND_AVG_SHIFT	6
 #define GROUND_AVG		(1 << GROUND_AVG_SHIFT)
 
 /* Pressure change (in Pa) to detect boost */
-#define BOOST_DETECT		120	/* 10m at sea level, 12m at 2000m */
+#define BOOST_DETECT		360	/* 30m at sea level, 36m at 2000m */
 
 /* Wait after power on before doing anything to give the user time to assemble the rocket */
 #define BOOST_DELAY		AO_SEC_TO_TICKS(60)