From 971e8fc4ffc6fc50ffaf257c473dfa86f5dc2d11 Mon Sep 17 00:00:00 2001
From: TickTock- <lukecell@safe-mail.net>
Date: Tue, 22 Apr 2014 23:19:04 -0700
Subject: [PATCH] Made failsafe more intuitive.  Default (0) maps to whatever
 channel is throttle.  If a non-zero value is entered, a direct channel map is
 used so use

---
 src/modules/sensors/sensor_params.c | 23 ++++-------------------
 src/modules/sensors/sensors.cpp     |  5 ++++-
 2 files changed, 8 insertions(+), 20 deletions(-)

diff --git a/src/modules/sensors/sensor_params.c b/src/modules/sensors/sensor_params.c
index 48e5d80e73..a19180ad4b 100644
--- a/src/modules/sensors/sensor_params.c
+++ b/src/modules/sensors/sensor_params.c
@@ -538,28 +538,13 @@ PARAM_DEFINE_INT32(RC_MAP_PITCH, 2);
 /**
  * Failsafe channel mapping.
  *
- * The RC mapping index indicates which rc function
- * should be used for detecting the failsafe condition
+ * The RC mapping index indicates which channel is used for failsafe
+ * If 0, whichever channel is mapped to throttle is used
+ * otherwise the value indicates the specific rc channel to use
  *
  * @min 0
- * @max 14
+ * @max 18
  *
- * mapping (from rc_channels.h)
- * 	THROTTLE = 0,
-	ROLL     = 1,
-	PITCH    = 2,
-	YAW      = 3,
-	MODE = 4,
-	RETURN = 5,
-	ASSISTED = 6,
-	MISSION = 7,
-	OFFBOARD_MODE = 8,
-	FLAPS   = 9,
-	AUX_1   = 10,
-	AUX_2   = 11,
-	AUX_3   = 12,
-	AUX_4   = 13,
-	AUX_5   = 14,
  *
  */
 PARAM_DEFINE_INT32(RC_MAP_FAILSAFE, 0);  //Default to throttle function
diff --git a/src/modules/sensors/sensors.cpp b/src/modules/sensors/sensors.cpp
index caf0ff6fe0..28c08422e1 100644
--- a/src/modules/sensors/sensors.cpp
+++ b/src/modules/sensors/sensors.cpp
@@ -1379,7 +1379,10 @@ Sensors::rc_poll()
 			signal_lost = false;
 
 			/* check failsafe */
-			int8_t fs_ch = _rc.function[_parameters.rc_map_failsafe];
+			int8_t fs_ch = _rc.function[_parameters.rc_map_failsafe]; // get channel mapped to throttle
+			if (_parameters.rc_map_failsafe>0){ // if not 0, use channel number instead of rc.function mapping
+				fs_ch = _parameters.rc_map_failsafe - 1;
+			}
 			if (_parameters.rc_fails_thr > 0 && fs_ch >= 0) {
 				/* failsafe configured */
 				if ((_parameters.rc_fails_thr < _parameters.min[fs_ch] && rc_input.values[fs_ch] < _parameters.rc_fails_thr) ||