fix #54, calibrate() (#55)

- fix #54, calibrate() function, Kudos to jens-kuerten and MArimont3
- minor edits

Author: RobTillaart

CHANGELOG.md

@@ -6,13 +6,18 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/)
 and this project adheres to [Semantic Versioning](http://semver.org/).
 
 
+## [0.6.0] - 2024-06-22
+- fix #54, calibrate() function, Kudos to jens-kuerten and MArimont3
+- minor edits
+
+----
+
 ## [0.5.3] - 2024-05-08
 - fix #52, add **uint8_t getAddrress()**
 - fix #51, add **bool setDLPFMode(uint8_t mode)** and **uint8_t getDLPFMode()**
 - add const float GRAVITY=9.80655;
 - minor edits
 
-
 ## [0.5.2] - 2024-01-16
 - fix #48, use float variables in example GY521_test_1.ino
 - add **void calibrate(uint16_t times)** to API
@@ -72,7 +77,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - update library.json, license, minor edits
 
 ## [0.3.5] - 2021-10-20
-- update build-CI, badges 
+- update build-CI, badges
 - fix #28 add wakeup to begin().
 
 ## [0.3.4] - 2021-07-12
@@ -85,7 +90,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - fix #20 support multiWire
 
 ## [0.3.1] - 2021-06-13
-- added more unit test 
+- added more unit test
 - some initialization
 
 ## [0.3.0] - 2021-04-07

GY521.cpp

@@ -1,7 +1,7 @@
 //
 //    FILE: GY521.cpp
 //  AUTHOR: Rob Tillaart
-// VERSION: 0.5.3
+// VERSION: 0.6.0
 // PURPOSE: Arduino library for I2C GY521 accelerometer-gyroscope sensor
 //     URL: https://github.com/RobTillaart/GY521
 
@@ -78,31 +78,39 @@ void GY521::calibrate(uint16_t times)
   bool oldThrottle = _throttle;
   _throttle = false;
 
-  //  set errors to zero
+  //  set all errors to zero, to get the raw reads.
   axe = aye = aze = 0;
   gxe = gye = gze = 0;
 
+  //  use local error sums, to calculate the average error.
+  float _axe = 0, _aye = 0, _aze = 0;
+  float _gxe = 0, _gye = 0, _gze = 0;
+
+  //  adjust times if zero.
+  if (times == 0) times = 1;
+
+  //  summarize (6x) the measurements.
   for (uint16_t i = 0; i < times; i++)
   {
     read();
-    axe -= getAccelX();
-    aye -= getAccelY();
-    aze -= getAccelZ();
-    gxe -= getGyroX();
-    gye -= getGyroY();
-    gze -= getGyroZ();
+    _axe -= getAccelX();
+    _aye -= getAccelY();
+    _aze -= getAccelZ();
+    _gxe -= getGyroX();
+    _gye -= getGyroY();
+    _gze -= getGyroZ();
   }
 
-  //  adjust calibration errors so table should get all zero's.
+  //  adjust calibration errors so read() should get all zero's on average.
   float factor = 1.0 / times;
-  axe *= factor;
-  aye *= factor;
-  aze *= factor;
-  gxe *= factor;
-  gye *= factor;
-  gze *= factor;
-
-  //  restore throttle state
+  axe = _axe * factor;
+  aye = _aye * factor;
+  aze = _aze * factor;
+  gxe = _gxe * factor;
+  gye = _gye * factor;
+  gze = _gze * factor;
+
+  //  restore throttle state.
   _throttle = oldThrottle;
 }
 

GY521.h

@@ -2,7 +2,7 @@
 //
 //    FILE: GY521.h
 //  AUTHOR: Rob Tillaart
-// VERSION: 0.5.3
+// VERSION: 0.6.0
 // PURPOSE: Arduino library for I2C GY521 accelerometer-gyroscope sensor
 //     URL: https://github.com/RobTillaart/GY521
 
@@ -11,7 +11,7 @@
 #include "Wire.h"
 
 
-#define GY521_LIB_VERSION           (F("0.5.3"))
+#define GY521_LIB_VERSION           (F("0.6.0"))
 
 const float GRAVITY = 9.80655;
 

README.md

@@ -24,6 +24,11 @@ It needs to be tested a lot more.
 See changelog.md for latest updates.
 
 
+#### 0.6.0
+
+Fixed a bug in calibration function, making previous versions obsolete.
+
+
 #### 0.5.0 Breaking change
 
 Version 0.5.0 introduced a breaking change.

library.json

@@ -15,7 +15,7 @@
     "type": "git",
     "url": "https://github.com/RobTillaart/GY521.git"
   },
-  "version": "0.5.3",
+  "version": "0.6.0",
   "license": "MIT",
   "frameworks": "*",
   "platforms": "*",

library.properties

@@ -1,5 +1,5 @@
 name=GY521
-version=0.5.3
+version=0.6.0
 author=Rob Tillaart <[email protected]>
 maintainer=Rob Tillaart <[email protected]>
 sentence=Arduino library for GY521 angle measurement