0.3.7 GY521

Author: RobTillaart

libraries/GY521/GY521.cpp

@@ -1,7 +1,7 @@
 //
 // FILE: GY521.cpp
 // AUTHOR: Rob Tillaart
-// VERSION: 0.3.6
+// VERSION: 0.3.7
 // PURPOSE: Arduino library for I2C GY521 accelerometer-gyroscope sensor
 // URL: https://github.com/RobTillaart/GY521
 //
@@ -12,18 +12,23 @@
 // 0.1.3 2020-08-07 fix ESP support + pitch roll yaw demo
 // 0.1.4 2020-09-29 fix #5 missing ;
 // 0.1.5 2020-09-29 fix #6 fix maths for Teensy
+//
 // 0.2.0 2020-11-03 improve error handling
 // 0.2.1 2020-12-24 Arduino-CI + unit tests
 // 0.2.2 2021-01-24 add interface part to readme.md
 // add GY521_registers.h
 // 0.2.3 2021-01-26 align version numbers (oops)
+//
 // 0.3.0 2021-04-07 fix #18 acceleration error correction (kudo's to Merkxic)
 // 0.3.1 2021-06-13 added more unit test + some initialization
 // 0.3.2 2021-07-05 fix #20 support multiWire
 // 0.3.3 2021-07-05 fix #22 improve maths
 // 0.3.4 2021-07-12 fix #24 improve precision
 // 0.3.5 2021-10-20 update build-CI, badges + #28 add wakeup to begin().
 // 0.3.6 2021-12-18 update library.json, license, minor edits
+// 0.3.7 2022-07-26 add partial reads readAccel(),
+// readGyro() and readTemperature()
+// rename + add GY521_LIB_VERSION to examples.
 
 
 #include "GY521.h"
@@ -198,6 +203,152 @@ int16_t GY521::read()
 }
 
 
+int16_t GY521::readAccel()
+{
+ uint32_t now = millis();
+ if (_throttle)
+ {
+ if ((now - _lastTime) < _throttleTime)
+ {
+ // not an error.
+ return GY521_THROTTLED;
+ }
+ }
+ _lastTime = now;
+
+ // Connected ?
+ _wire->beginTransmission(_address);
+ _wire->write(GY521_ACCEL_XOUT_H);
+ if (_wire->endTransmission() != 0)
+ {
+ _error = GY521_ERROR_WRITE;
+ return _error;
+ }
+
+ // Get the data
+ int8_t n = _wire->requestFrom(_address, (uint8_t)6);
+ if (n != 6)
+ {
+ _error = GY521_ERROR_READ;
+ return _error;
+ }
+ // ACCELEROMETER
+ _ax = _WireRead2(); // ACCEL_XOUT_H ACCEL_XOUT_L
+ _ay = _WireRead2(); // ACCEL_YOUT_H ACCEL_YOUT_L
+ _az = _WireRead2(); // ACCEL_ZOUT_H ACCEL_ZOUT_L
+
+ // next lines might be merged per axis.
+
+ // Convert raw acceleration to g's
+ _ax *= _raw2g;
+ _ay *= _raw2g;
+ _az *= _raw2g;
+
+ // Error correct raw acceleration (in g) measurements // #18 kudos to Merkxic
+ _ax += axe;
+ _ay += aye;
+ _az += aze;
+
+ // prepare for Pitch Roll Yaw
+ float _ax2 = _ax * _ax;
+ float _ay2 = _ay * _ay;
+ float _az2 = _az * _az;
+
+ _aax = atan( _ay / sqrt(_ax2 + _az2)) * RAD2DEGREES;
+ _aay = atan(-1.0 * _ax / sqrt(_ay2 + _az2)) * RAD2DEGREES;
+ _aaz = atan( _az / sqrt(_ax2 + _ay2)) * RAD2DEGREES;
+ // optimize #22
+ // _aax = atan(_ay / hypot(_ax, _az)) * RAD2DEGREES;
+ // _aay = atan(-1.0 * _ax / hypot(_ay, _az)) * RAD2DEGREES;
+ // _aaz = atan(_az / hypot(_ax, _ay)) * RAD2DEGREES;
+
+ return GY521_OK;
+}
+
+
+int16_t GY521::readGyro()
+{
+ uint32_t now = millis();
+ if (_throttle)
+ {
+ if ((now - _lastTime) < _throttleTime)
+ {
+ // not an error.
+ return GY521_THROTTLED;
+ }
+ }
+ _lastTime = now;
+
+ // Connected ?
+ _wire->beginTransmission(_address);
+ _wire->write(GY521_GYRO_XOUT_H);
+ if (_wire->endTransmission() != 0)
+ {
+ _error = GY521_ERROR_WRITE;
+ return _error;
+ }
+
+ // Get the data
+ int8_t n = _wire->requestFrom(_address, (uint8_t)6);
+ if (n != 6)
+ {
+ _error = GY521_ERROR_READ;
+ return _error;
+ }
+ // GYROSCOPE
+ _gx = _WireRead2(); // GYRO_XOUT_H GYRO_XOUT_L
+ _gy = _WireRead2(); // GYRO_YOUT_H GYRO_YOUT_L
+ _gz = _WireRead2(); // GYRO_ZOUT_H GYRO_ZOUT_L
+
+ // duration interval
+ now = micros();
+ float duration = (now - _lastMicros) * 1e-6; // duration in seconds.
+ _lastMicros = now;
+
+ // next lines might be merged per axis.
+
+ // Convert raw Gyro to degrees/seconds
+ _gx *= _raw2dps;
+ _gy *= _raw2dps;
+ _gz *= _raw2dps;
+
+ // Error correct raw gyro measurements.
+ _gx += gxe;
+ _gy += gye;
+ _gz += gze;
+
+ _gax += _gx * duration;
+ _gay += _gy * duration;
+ _gaz += _gz * duration;
+
+ return GY521_OK;
+}
+
+
+int16_t GY521::readTemperature()
+{
+ // DO NOT THROTTLE
+ _wire->beginTransmission(_address);
+ _wire->write(GY521_TEMP_OUT_H);
+ if (_wire->endTransmission() != 0)
+ {
+ _error = GY521_ERROR_WRITE;
+ return _error;
+ }
+
+ // Get the data
+ int8_t n = _wire->requestFrom(_address, (uint8_t)2);
+ if (n != 2)
+ {
+ _error = GY521_ERROR_READ;
+ return _error;
+ }
+ // TEMPERATURE
+ _temperature = _WireRead2(); // TEMP_OUT_H TEMP_OUT_L
+ return GY521_OK;
+}
+
+
 bool GY521::setAccelSensitivity(uint8_t as)
 {
  _afs = as;

libraries/GY521/GY521.h

@@ -2,7 +2,7 @@
 //
 // FILE: GY521.h
 // AUTHOR: Rob Tillaart
-// VERSION: 0.3.6
+// VERSION: 0.3.7
 // PURPOSE: Arduino library for I2C GY521 accelerometer-gyroscope sensor
 // URL: https://github.com/RobTillaart/GY521
 //
@@ -15,15 +15,15 @@
 #include "Wire.h"
 
 
-#define GY521_LIB_VERSION (F("0.3.6"))
+#define GY521_LIB_VERSION (F("0.3.7"))
 
 
 #ifndef GY521_THROTTLE_TIME
 #define GY521_THROTTLE_TIME 10 // milliseconds
 #endif
 
 
-// ERROR CODES
+//  ERROR CODES
 #define GY521_OK 0
 #define GY521_THROTTLED 1
 #define GY521_ERROR_READ -1
@@ -46,26 +46,35 @@ class GY521
 
 
  bool wakeup();
- // throttle to force delay between reads.
+ //  throttle to force delay between reads.
  void setThrottle(bool throttle = true) { _throttle = throttle; };
  bool getThrottle() { return _throttle; };
- // 0..65535 (max milliseconds == roughly 1 minute.
+ //  0..65535 (max milliseconds == roughly 1 minute.
  void setThrottleTime(uint16_t ti ) { _throttleTime = ti; };
  uint16_t getThrottleTime() { return _throttleTime; };
 
 
- // returns GY521_OK or one of the error codes above.
+ // READ THE SENSOR
+ // returns GY521_OK or one of the error codes above.
  int16_t read();
-
- // SET BEFORE READ
- // as = 0,1,2,3 ==> 2g 4g 8g 16g
+ // optimized partial reading
+ // read accelerometer only
+ int16_t readAccel();
+ // read gyroscope only can be done too
+ // however for pitch roll yaw you need all.
+ int16_t readGyro();
+ // read temperature only, does not affect throttle.
+ int16_t readTemperature();
+
+ // SET BEFORE READ
+ // as = 0,1,2,3 ==> 2g 4g 8g 16g
  bool setAccelSensitivity(uint8_t as);
  uint8_t getAccelSensitivity(); // returns 0,1,2,3
- // gs = 0,1,2,3 ==> 250, 500, 1000, 2000 degrees/second
+ //  gs = 0,1,2,3 ==> 250, 500, 1000, 2000 degrees/second
  bool setGyroSensitivity(uint8_t gs);
  uint8_t getGyroSensitivity(); // returns 0,1,2,3
 
- // CALL AFTER READ
+ //  CALL AFTER READ
  float getAccelX() { return _ax; };
  float getAccelY() { return _ay; };
  float getAccelZ() { return _az; };
@@ -81,20 +90,20 @@ class GY521
  float getYaw() { return _yaw; };
 
 
- // last time sensor is actually read.
+ //  last time sensor is actually read.
  uint32_t lastTime() { return _lastTime; };
 
 
- // generic worker to get access to all functionality
+ //  generic worker to get access to all functionality
  uint8_t setRegister(uint8_t reg, uint8_t value);
  uint8_t getRegister(uint8_t reg);
 
 
- // get last error and reset error to OK.
+ //  get last error and reset error to OK.
  int16_t getError() { return _error; _error = GY521_OK; };
 
 
- // calibration errors
+ //  calibration errors
  float axe = 0, aye = 0, aze = 0; // accelerometer errors
  float gxe = 0, gye = 0, gze = 0; // gyro errors
 

libraries/GY521/README.md

@@ -87,13 +87,20 @@ AD0 connected to VCC => 0x69
 - **bool setAccelSensitivity(uint8_t as)** as = 0, 1, 2, 3 ==> 2g 4g 8g 16g
 - **uint8_t getAccelSensitivity()** returns 0, 1, 2, 3
 - **bool setGyroSensitivity(uint8_t gs)** gs = 0,1,2,3 ==> 250, 500, 1000, 2000 degrees/second
-- **uint8_t  getGyroSensitivity()** returns 0, 1, 2, 3 
+- **uint8_t getGyroSensitivity()** returns 0, 1, 2, 3 
 
 
 #### Actual read
 
-- **int16_t read()** returns ...
-- **uint32_t lastTime()** last time sensor is actually read. In milliseconds.
+- **int16_t read()** returns status = GY521_OK on success.
+- **int16_t readAccel()** read accelerometer only to speed up interaction. This call does update the throttle timer.
+returns status = GY521_OK on success.
+- **int16_t readGyro()** read gyroscope only to speed up interaction. This call does update the throttle timer.
+returns status = GY521_OK on success.
+Note: for pitch roll yaw you need to call **read()**.
+- **int16_t readTemperature()** read temperature only, does **not** update the throttle timer.
+returns status = GY521_OK on success.
+- **uint32_t lastTime()** last time sensor is actually read. In milliseconds. Not updated by readTemperature().
 
 
 #### Call after read
@@ -144,5 +151,4 @@ See examples, use with care
 **Could**
 - calibrate function in the lib ? (think not as lib might grow?)
 - calibrate sketch could print code snippet to include...
-- option to read only Accel?
-- option to read only Gyro?
+

libraries/GY521/examples/GY521_angle/GY521_angle.ino

@@ -0,0 +1,74 @@
+//
+// FILE: GY521_angle.ino
+// AUTHOR: Rob Tillaart
+// PURPOSE: demo pitch roll yaw
+// DATE: 2022-06-06
+
+
+#include "GY521.h"
+
+GY521 sensor(0x68);
+
+uint32_t counter = 0;
+
+
+void setup()
+{
+ Serial.begin(115200);
+ Serial.println();
+ Serial.println(__FILE__);
+ Serial.print("GY521_LIB_VERSION: ");
+ Serial.println(GY521_LIB_VERSION);
+
+ Wire.begin();
+
+ delay(100);
+ while (sensor.wakeup() == false)
+ {
+ Serial.print(millis());
+ Serial.println("\tCould not connect to GY521");
+ delay(1000);
+ }
+ sensor.setAccelSensitivity(2); // 8g
+ sensor.setGyroSensitivity(1); // 500 degrees/s
+
+ sensor.setThrottle();
+ Serial.println("start...");
+
+ // set calibration values from calibration sketch.
+ sensor.axe = 0.574;
+ sensor.aye = -0.002;
+ sensor.aze = -1.043;
+ sensor.gxe = 10.702;
+ sensor.gye = -6.436;
+ sensor.gze = -0.676;
+}
+
+
+void loop()
+{
+ sensor.read();
+ float x = sensor.getAngleX();
+ float y = sensor.getAngleY();
+ float z = sensor.getAngleZ();
+
+ if (counter % 10 == 0)
+ {
+ // Serial.println("\nCNT\tX\tY\tZ");
+ }
+
+ //Serial.print(counter);
+ //Serial.print('\t');
+ Serial.print(x, 1);
+ Serial.print('\t');
+ Serial.print(y, 1);
+ Serial.print('\t');
+ Serial.print(z, 1);
+ Serial.println();
+
+ counter++;
+}
+
+
+// -- END OF FILE --
+

libraries/GY521/examples/GY521_performance/GY521_performance.ino

@@ -16,7 +16,10 @@ uint32_t counter = 0;
 void setup()
 {
  Serial.begin(115200);
+ Serial.println();
  Serial.println(__FILE__);
+ Serial.print("GY521_LIB_VERSION: ");
+ Serial.println(GY521_LIB_VERSION);
 
  Wire.begin();