From c62792a86436d189f4313daeab48a6309e7e00b4 Mon Sep 17 00:00:00 2001
From: Eggert Jung <eggert.s.jung@wischhof13.de>
Date: Mon, 5 Sep 2022 17:10:22 +0200
Subject: [PATCH] zero sensor value when both buttons pressed

---
 kraftsensor.c | 4 +++-
 kraftsensor.h | 2 ++
 taenzer.c     | 8 ++++++++
 3 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/kraftsensor.c b/kraftsensor.c
index 621872b..823daac 100644
--- a/kraftsensor.c
+++ b/kraftsensor.c
@@ -12,6 +12,8 @@
 int32_t kraftsensor_value;
 uint8_t kraftsensor_valid;
 
+int32_t kraftsensor_zero_offset = 0/*197700*/;
+
 void timer2_init()
 {
     TCCR2A = (1<<WGM21); //TIMER0 SET-UP: CTC MODE
@@ -45,7 +47,7 @@ void do_kraftsensor(){
 
         //kraftsensor_value = tmp;
         /* conversion magic to milliNewton */
-        kraftsensor_value = ((tmp + 197700 /*539363*/)*9.81)/177.380;
+        kraftsensor_value = (((tmp /* + 539363*/)*9.81)/177.380)+kraftsensor_zero_offset;
 
         //if(abs(kraftsensor_read - old_value) > 10000){
         //    if(abs(last_read - kraftsensor_read) > 10000){
diff --git a/kraftsensor.h b/kraftsensor.h
index 23e75ab..b0acbe1 100644
--- a/kraftsensor.h
+++ b/kraftsensor.h
@@ -8,6 +8,8 @@
 extern int32_t kraftsensor_value;
 extern uint8_t kraftsensor_valid;
 
+extern int32_t kraftsensor_zero_offset;
+
 void timer2_init();
 void kraftsensor_init();
 void do_kraftsensor(void);
diff --git a/taenzer.c b/taenzer.c
index 37875c3..da72467 100644
--- a/taenzer.c
+++ b/taenzer.c
@@ -68,12 +68,20 @@ void do_taenzer(){
 #if PLC_MQTT_ENABLED
         send_settings();
 #endif
+        if(taenzer_state.homed == 1 && read_Input(BTN_KRAFT_MINUS, LEVEL))
+        {
+            kraftsensor_zero_offset = -(kraftsensor_value-kraftsensor_zero_offset);
+        }
     }
     if (read_Input(BTN_KRAFT_MINUS, RISING)) {
         taenzer_state.force_setpoint -= 1000;
 #if PLC_MQTT_ENABLED
         send_settings();
 #endif
+        if(taenzer_state.homed == 1 && read_Input(BTN_KRAFT_PLUS, LEVEL))
+        {
+            kraftsensor_zero_offset = -(kraftsensor_value-kraftsensor_zero_offset);
+        }
     }
     if (read_Input(BTN_TAENZER_START, RISING)) {
         taenzer_state.active = 1;