fixes accel/gyro range issues

Partial fix for #10

The issue sparkfun/SparkFun_LSM9DS1_Arduino_Library#27 is
worked around by pulling CAP1Sup/Arduino_LSM9DS1, which has a fix
applied, instead of Sparkfun's original (apparently unmaintained)
library.

I also made adjustments to the full scale ranges of the accelerometer
and magnetometer based on my experimentation, with notes in the source
code describing my reasoning.

firmware/platformio.ini

@@ -16,7 +16,7 @@ lib_deps =
 	https://github.com/Puara/puara-gestures.git
 	https://github.com/mathiasbredholt/libmapper-arduino.git#v0.3
 	https://github.com/Puara/puara-module.git
-	sparkfun/SparkFun LSM9DS1 IMU@^2.0.0
+	https://github.com/CAP1Sup/Arduino_LSM9DS1.git
 	tinypico/TinyPICO Helper Library@^1.4.0
 	https://github.com/BelaPlatform/Trill-Arduino.git
 build_flags = 

firmware/src/lsm9ds1.cpp

@@ -21,7 +21,6 @@
 #define beta sqrt(3.0f / 4.0f) * GyroMeasError   // compute beta
 #define zeta sqrt(3.0f / 4.0f) * GyroMeasDrift   // compute zeta, the other free parameter in the Madgwick scheme usually set to a small or zero value
 
-
 LSM9DS1 myIMU; // initialize library class
 
 // Initializing IMU
@@ -33,6 +32,7 @@ LSM9DS1 myIMU; // initialize library class
             myIMU.settings.gyro.enabled = true;
         // [scale] sets the full-scale range of the gyroscope.
         // scale can be set to either 245, 500, or 2000 dps
+        // Travis West 2022-11-02: I was able to saturate the output with 2000 dps, so this seems like an appropriate setting.
             myIMU.settings.gyro.scale = 2000;
         // [sampleRate] sets the output data rate (ODR) of the gyro
         // sampleRate can be set between 1-6
@@ -68,7 +68,12 @@ LSM9DS1 myIMU; // initialize library class
             myIMU.settings.accel.enableZ = true; // Enable Z
         // [scale] sets the full-scale range of the accelerometer.
         // accel scale can be 2, 4, 8, or 16 g's
-            myIMU.settings.accel.scale = 16;
+        // Travis West 2022-11-02: In my experiments I found that the effort required
+        // to get much more than 7.5 g of acceleration was significant enough that I
+        // was worried about causing damage the internal wiring of the instrument.
+        // As such, I think 8 g full scale range or less is appropriate, at least
+        // until such time as the mechanical robustness of the instrument is improved.
+            myIMU.settings.accel.scale = 8;
         // [sampleRate] sets the output data rate (ODR) of the
         // accelerometer. ONLY APPLICABLE WHEN THE GYROSCOPE IS
         // DISABLED! Otherwise accel sample rate = gyro sample rate.
@@ -98,7 +103,13 @@ LSM9DS1 myIMU; // initialize library class
             myIMU.settings.mag.enabled = true; // Enable magnetometer
         // [scale] sets the full-scale range of the magnetometer
         // mag scale can be 4, 8, 12, or 16 Gs
-            myIMU.settings.mag.scale = 16;
+        // Travis West 2022-11-02: Considering that the Earth's magnetic field is
+        // generally less than 1 Gs, the lowest setting available is likely best.
+        // A higher setting could be used if the sensor were installed next to a
+        // strong magnetic field, such as a magnet or speaker, since then the reading
+        // would not be saturated and the bias from the magnet could potentially be
+        // removed.
+            myIMU.settings.mag.scale = 4;
         // [sampleRate] sets the output data rate (ODR) of the
         // magnetometer.
         // mag data rate can be 0-7:
@@ -351,4 +362,4 @@ void Imu_LSM9DS1::taitBryanAngles(float w, float x, float y, float z) {
     //   } else {
     //     Imu_LSM9DS1::yaw += offsetYaw;
     //   }
-}
+}