tag:dreamwidth.org,2009-04-20:105601 Craft and Tech Notebook chebe 2025-03-19T14:40:57Z tag:dreamwidth.org,2009-04-20:105601:160808 2025-03-19T12:36:48Z 2025-03-19T14:40:57Z public 0 Compare and contrast getting normalized accelerometer values, where the raw value is -13248.00. (A.k.a. Please, make it make sense.)<br /><br />Library 1; jarzebski's Arduino-MPU6050 - <a href="https://github.com/jarzebski/Arduino-MPU6050/">https://github.com/jarzebski/Arduino-MPU6050/</a><br />Library 2; Adafruit's Adafruit_MPU6050 - <a href="https://github.com/adafruit/Adafruit_MPU6050">https://github.com/adafruit/Adafruit_MPU6050</a><br />Library 3; i2cdevlib/ElectronicCats' mpu6050 - <a href="https://github.com/ElectronicCats/mpu6050">https://github.com/ElectronicCats/mpu6050</a><br /><br /><br /><h3>Library 1;</h3><br /><span class="cut-wrapper"><span style="display: none;" id="span-cuttag___1" class="cuttag"></span><b class="cut-open">(&nbsp;</b><b class="cut-text"><a href="https://chebe.dreamwidth.org/160808.html#cutid1">code</a></b><b class="cut-close">&nbsp;)</b></span><div style="display: none;" id="div-cuttag___1" aria-live="assertive"></div><br /><br />Formula for normalized acceleration value at MPU6050_RANGE_2G;<br />raw * rangePerDigit * gravityConst<br />(raw * (1.0/16384)) * gravityConst<br />== (raw / 16384) * gravityConst<br />(-13248.00 * .000061) * 9.80665 = -7.92502845<br />== (-13248.00 / 16384) * 9.80665 = -7.92959589<br /><br /><br /><h3>Library 2;</h3><br /><span class="cut-wrapper"><span style="display: none;" id="span-cuttag___2" class="cuttag"></span><b class="cut-open">(&nbsp;</b><b class="cut-text"><a href="https://chebe.dreamwidth.org/160808.html#cutid2">code</a></b><b class="cut-close">&nbsp;)</b></span><div style="display: none;" id="div-cuttag___2" aria-live="assertive"></div><br /><br />Formula for normalized acceleration value at MPU6050_RANGE_2_G;<br />(raw / accel_scale) * gravityConst<br />(-13248.00 / 16384) * 9.80665 = -7.92959589<br /><br /><br /><h3>Library 3;</h3><br /><span class="cut-wrapper"><span style="display: none;" id="span-cuttag___3" class="cuttag"></span><b class="cut-open">(&nbsp;</b><b class="cut-text"><a href="https://chebe.dreamwidth.org/160808.html#cutid3">code</a></b><b class="cut-close">&nbsp;)</b></span><div style="display: none;" id="div-cuttag___3" aria-live="assertive"></div><br /><br />No normalized functions in MPU6050.cpp. Can use MotionApps files, but they go through Quaternions.<br /><span class="cut-wrapper"><span style="display: none;" id="span-cuttag___4" class="cuttag"></span><b class="cut-open">(&nbsp;</b><b class="cut-text"><a href="https://chebe.dreamwidth.org/160808.html#cutid4">code</a></b><b class="cut-close">&nbsp;)</b></span><div style="display: none;" id="div-cuttag___4" aria-live="assertive"></div><br /><br />Formula for normalized acceleration value at MPU6050_ACCEL_FS_2;<br />// jarzebski way;<br />raw * accelerationResolution * gravityConst<br />-13248.00 * 0.000122 * 9.80665 = -15.850057<br /><br />// adafruit way;<br />// (raw * (1.0/16384)) * gravityConst<br />// (raw * (2.0/16384)) * gravityConst<br />(-13248.00 / (2.0*16384)) * 9.80665 = -15.85919<br />((-13248.00*2.0) / 16384) * 9.80665 = -15.85919<br /><br />Result is twice that of the others. <code>accelerationResolution</code> itself seems to be twice the others, so half it? Not sure if this is a mistake, or I'm missing something about MPU6050_ACCEL_FS_2 vs MPU6050_RANGE_2_G.<br />raw * (accelerationResolution/2) * gravityConst<br />-13248.00 * (accelerationResolution/2) * 9.80665 = -7.9250<br /><br /><code>accelerationResolution</code> and <code>get_acce_resolution()</code> only exist in the ElectronicCats version, they're not accessible in the <a href="https://github.com/jrowberg/i2cdevlib/tree/master/Arduino/MPU6050">i2cdevlibs</a> version. That version seems to <strong>really</strong> want you to use the Quaternion path. But you can always use the range values from the other versions yourself on the raw values.<br /><br /><img src="https://www.dreamwidth.org/tools/commentcount?user=chebe&ditemid=160808" width="30" height="12" alt="comment count unavailable" style="vertical-align: middle;"/> comments