Useful links

Some helpful internet links for the development process

Materials

Material selector https://www.kern.de/de/richtwerttabelle

Parts

Magnetometer comparison http://ejtech.blogspot.de/2014/03/mpu9150-vs-hmc5883l-trade-off-analysis.html

https://github.com/kriswiner/MPU6050/wiki/9-DoF-Motion-Sensor-Bakeoff

https://github.com/kriswiner/MPU6050/issues/6

Sparkfun MP-9250 Library

• With DMP
• https://learn.sparkfun.com/tutorials/9dof-razor-imu-m0-hookup-guide#using-the-mpu-9250-dmp-arduino-library
• https://github.com/sparkfun/SparkFun_MPU-9250-DMP_Arduino_Library
• https://github.com/bolderflight/MPU9250

SPI

• Interrupt driven or not? https://www.tablix.org/~avian/blog/archives/2012/06/spi_interrupts_versus_polling/
• SPI for teensy
  • https://github.com/xxxajk/spi4teensy3
  • https://www.pjrc.com/teensy/td_libs_SPI.html
• DMA SPI https://github.com/crteensy/DmaSpi
• MPU-0250 via SPI http://forward-in-code.blogspot.de/2016/10/invensense-mpu9250-via-spi.html

Sensor calibration

Magnetometer

• https://github.com/kriswiner/MPU6050/wiki/Simple-and-Effective-Magnetometer-Calibration
• Calibrating an eCompass in the Presence of Hard- and Soft-Iron Interference
• Advanced hard and soft iron magnetometer calibration for dummies

Sensor fusion

• https://github.com/kriswiner/MPU6050/wiki/affordable-9-dof-sensor-fusion
• https://www.tindie.com/products/onehorse/ultimate-sensor-fusion-solution/
• https://learn.sparkfun.com/tutorials/mpu-9250-hookup-guide
• https://github.com/kriswiner/MPU9250
• http://x-io.co.uk/open-source-imu-and-ahrs-algorithms/
• http://www.olliw.eu/2013/imu-data-fusing/
• http://www.lucidarme.me/?p=5057

Signal processing

• INTRODUCTION TO DIGITAL FILTERS: https://www.dsprelated.com/freebooks/filters/
• direct form I is usually the best choice for fixed point, and transposed direct form II for floating point.
  • http://www.earlevel.com/main/2003/02/28/biquads/
  • https://rosettacode.org/wiki/Apply_a_digital_filter_(direct_form_II_transposed)#C.2B.2B
  • https://www.kvraudio.com/forum/viewtopic.php?t=94101

Mathematics

• Fast inverse square root https://pizer.wordpress.com/2008/10/12/fast-inverse-square-root/
• Latex formula generator: http://www.hostmath.com/

Ellipsoid fitting

• Least-Squares Fitting of a Three-Dimensional Ellipsoid to Noisy Data
• Multi-dimensional Ellipsoidal Fitting
• Ellipsoid or sphere fitting for sensor calibration
• FITTING ELLIPSOIDS BY LEAST SQUARES
• A way to calibrate a magnetometer

Wireless

• Wireless Serial: http://blog.circuits4you.com/2016/04/wireless-serial-using-nrf24l01.html
• NRF24L01 Library http://tmrh20.github.io/RF24/
  • https://github.com/nRF24/RF24
  • https://www.mikrocontroller.net/articles/NRF24L01_Tutorial
  • http://www.airspayce.com/mikem/arduino/RadioHead/index.html
  • http://arduino-info.wikispaces.com/Nrf24L01-2.4GHz-HowTo
• NRF24L1 Tutorial: http://howtomechatronics.com/tutorials/arduino/arduino-wireless-communication-nrf24l01-tutorial/

Rechargeable battery

• Lademodul http://www.watterott.com/de/TP4056-Micro-USB-5V-1A-Lithium-Battery-Charger-with-Protection
• Akku 14500 ca. 16mm x 65 mm 39g entspricht Mignon AA
• Oder 10450 ca, 10mm x 45mm 9g entspricht Micro AAA

Arduino / Programming

• Write a library: https://www.arduino.cc/en/Hacking/LibraryTutorial
• For Speedy Float Math, Specify the Float Version

Matlab

• 3D-Visualization: http://www.matrixlab-examples.com/simple-animation-3d.html

Visualization

• With Processing, kike here: https://github.com/arduino-libraries/MadgwickAHRS/tree/master/extras/Visualizer
  • https://processing.org/download/

Ultrasonic measurement

• reverse engineered HC-SR04
  • https://uglyduck.ath.cx/ep/archive/2014/01/Making_a_better_HC_SR04_Echo_Locator.html
  • http://www.pcserviceselectronics.co.uk/arduino/Ultrasonic/electronics.php

Midi

• https://www.pjrc.com/teensy/td_libs_MIDI.html
• https://www.midi.org/specifications/item/midi-din-electrical-specification
• http://www.electronicsteacher.com/tutorial/midi-controller.php

DMX

• http://www.mathertel.de/Arduino/DMXShield.aspx

Debouncing

• http://www.ganssle.com/debouncing.htm