In the top left of the screen is the selector. A HUD is a Head-Up Display where, usually on fighter jets, crucial information is projected onto the windscreen in front of the pilot. By touching the HUD button, the dials can be reversed, so that it can be reflected in the car windscreen. Next to the HUD button are the orientation arrows . Touching these rotates the display through 90 degrees each time. By careful use of the HUD and orientation buttons, you can position your iPhone on the top dashboard and no matter which way round the iPhone is the display reflection will always be correctly oriented towards you.
In the Bottom left of the screen is the or Information button. Touch this to access information about the TrakPal and change and adjust the various settings.
Next to the button is the Centre button which resets the Accelerometer ball to the centre. Use this every time you reposition the TrakPal in your car.
The main part of the UI consists of 3 dials displaying either Speedometer, Accelerometer, Compass or Altimeter. Which dials are displayed can be selected via the menu. Tapping either of the background dials will bring them to the foreground. Tapping on a dial on the info menu will select the currently unselected dial.