Resources & Research - Apt3kStudio/Phone GitHub Wiki

Important Topics


Apps samples

  • Find My Phone: We should dig into the code and use what's relevant to our development. Find My Phone is an app that let you find a phone and by sending an intent which the phone companion app will process to sound an alarm.

Relevant Repos/Codes/How To


Technologies

  • Satellite navigation: how does gps satellites work

  • Beacon Tech Bluetooth Distance Calculator: An Android library providing APIs to interact with Beacons. How accurate are the estimates? At close proximity of about 1 meter, you can expect to see distance estimates between 0.5-2 meters. At further distances you will see more variation. At 20 meters or actual distance, the estimate provided by the library may vary from 10-40 meters. The variation is caused by noise on the signal measurement, along with signal reflections and obstructions.

  • Sonar: How does sonar work and Why is sonar and not radar used in water for tracking objects at greater depths?: Sonar is simply making use of an echo. When an animal or machine makes a noise, it sends sound waves into the environment around it. Those waves bounce off nearby objects, and some of them reflect back to the object that made the noise.

  • Google Fit Bluetooth Sensors API: The Google Fit Bluetooth Sensors API balances the energy of a Bluetooth by finding BLE devices. With the API, developers can find available devices, claim a device, and release a device. Bluetooth Low Energy (BLE) is designed to provide significantly lower power consumption. This allows Android apps to communicate with BLE devices that have stricter power requirements, such as proximity sensors, heart rate monitors, and fitness devices.

Inertial Measurement Unit (IMU), Sensors, Formula and more

Magnetic Declination Offset, Compass Declination and finding True North

Madgwick AHRS algorithm Android implementation - example coding and formula/algorithm and different suggestions on how to correct sensor drift and their offset with different filters.

Open source IMU and AHRS algorithms IMU and AHRS sensor fusion algorithm and camera stabilisation application demo videos on YouTube. The algorithm source code is available in C, C# and MATLAB

A New Quaternion-Based Kalman Filter for Real-Time Attitude Estimation Using the Two-Step Geometrically-Intuitive Correction Algorithm

An efficient orientation filter for inertial and inertial/magnetic sensor arrays by Sebastian O.H. Madgwick A complete use of MARG Sensors to get precise orientation

Location Inference using Accelerometers on Smartphones - The security and privacy risks posed by smartphone sensors such as microphones and cameras have been well documented. However, the importance of accelerometers have been largely ignored. We show that accelerometer readings can be used to infer the trajectory and starting point of an individual who is driving

Probabilistic Inertial Navigation (ProbIN) - a probabilistic dead reckoning method. We developed ProbIN to estimate a user’s indoor location using inertial and magnetic sensors when GPS signals are not available.

Magnetometer Calibration