+
+ /* apogee detect to drogue deploy:
+ *
+ * accelerometer: abs(velocity) > min_velocity + 2m/s
+ * OR
+ * barometer: fall at least 10m
+ *
+ * If the barometer saturates because the flight
+ * goes over its measuring range (about 53k'),
+ * requiring a 10m fall will avoid prematurely
+ * detecting apogee; the accelerometer will take
+ * over in that case and the integrated velocity
+ * measurement should suffice to find apogee
+ */
+ if (abs(ao_flight_vel) > ao_min_vel + ACCEL_VEL_APOGEE ||
+ ao_flight_pres > ao_min_pres + BARO_APOGEE)
+ {
+ /* ignite the drogue charge */
+ ao_ignite(ao_igniter_drogue);
+
+ /* slow down the telemetry system */
+ ao_telemetry_set_interval(AO_TELEMETRY_INTERVAL_RECOVER);
+
+ /* slow down the ADC sample rate */
+ ao_timer_set_adc_interval(10);
+
+ /* Enable RDF beacon */
+ ao_rdf_set(1);
+
+ /*
+ * Start recording min/max accel and pres for a while
+ * to figure out when the rocket has landed
+ */
+ /* Set the 'last' limits to max range to prevent
+ * early resting detection
+ */
+ ao_interval_min_accel = 0;
+ ao_interval_max_accel = 0x7fff;
+ ao_interval_min_pres = 0;
+ ao_interval_max_pres = 0x7fff;
+
+ /* initialize interval values */
+ ao_interval_end = ao_flight_tick + AO_INTERVAL_TICKS;
+
+ ao_interval_cur_min_pres = ao_interval_cur_max_pres = ao_flight_pres;
+ ao_interval_cur_min_accel = ao_interval_cur_max_accel = ao_flight_accel;
+
+ /* and enter drogue state */
+ ao_flight_state = ao_flight_drogue;
+ ao_wakeup(DATA_TO_XDATA(&ao_flight_state));
+ }
+
+ break;