The main scope for my thesis is to control a gimbal via Wi-Fi.Google Glass is a wearable technology with an optical head-mounted display developed by Google X, a semi-secret facility run by Google which makes major technological advancements. Since its release, Google Glass has been discontinued following accumulation of user feedback, both good and bad. Google decided to close the program in order to focus on future versions of Glass and to improve on the current platform. This has positive implications for this project since the technology being used is only available to a limited audience and is still considered to be cutting-edge technology. Unfortunately this also means that the amount of helpful resources available are minimal and there are only a handful of scholarly articles focussed on Glass, none of which involve gimbal control.
Glass displays information and exhibits hands-free control properties. It contains a multitude of hardware and software sensors. The operating system is based on Android 4.4.2 (API 19) and uses the Android Studio IDE to develop functional applications with real-world interactive elements. Some of the useful hardware sensors on Glass are:
- 3-axis accelerometer
- 3-axis gyroscope
- 3-axis magnetometer (compass)
- Ambient light sensor
- Proximity sensor
Glass also has software sensors which gives useful real-time data calculated from the hardware sensors. Some of the useful software sensors used in this project are:
- Rotation vector
- Linear Acceleration
- Corrected gyroscope
The rotation vector software sensor is the most useful for this project application. The rotation vector uses the gyroscope, accelerometer and magnetometer data to set up a matrix describing the rotation of the Glass. This information is then used to get quaternion values for the orientation of the Glass. The orientation of glass is described in terms of yaw, pitch and roll angles in degrees. Yaw, also called azimuth, is the angle of glass around the Y-axis (in the figure below) relative to magnetic north and perpendicular to the horizon. This value tends to be prone to electromagnetic interference
(EMI) in noisy environments. Since the application of this project is focussed on SAR, there generally shouldn’t be a lot of EMI during operation. Pitch is the angle of Glass around the X-axis relative to the horizon. Roll is the angle of Glass around the Z-axis relative to the horizon. Pitch and roll values are reliable and are not prone to interference, they can therefore be used to replace the functionality of the yaw angle when there is interference. These values are sent to the Arduino via
Wi-Fi to control the angle of the gimbal.