GPS Twin Odometers

Historic, Classic, or Vintage road rallies may permit digital dual odometers, clocks, and stopwatches. This app combines all three using timers and GPS devices built into Apple mobile devices.

GPS inputs are used strictly for distance measures along the rally route. Also, the displayed accuracy of two decimal places conforms to typical historic, classic, and vintage road rally restrictions.

However, it is possible to interpolate distance to three decimal places. There are tick marks to indicate the second decimal place number centered on the display as well as increments of +0.0025, +0.0050, and +0.0075. When touched, the Control button will pause the two odometers for 4 seconds to allow you time to estimate distance to thousandths.

Similarly, time measurements are limited to whole seconds or cents. Time, distance, and mode (discussed below) may be chosen at the start of a new rally by touching the Set button to access app Settings.

A set of buttons allows you to chose the active odometer. The leftmost button activates the lower "interval distance" odometer; the rightmost button activates the upper "total distance" odometer; the center button activates both odometers.

From time to time you may measure time and distance for a stage or a checkpoint and record data by touching the Control button. The time and distance will be stored in a log along with geographic coordinates.

Distance options include subtraction of distance when you travel off course. Direction buttons switch between forward (+), reverse (–), and park (0). Also, you may chose between miles or kilometers.

There are three modes of operation selectable in the app Settings: Regularity mode, Jogularity mode, and Lap mode. In Regularity mode, the stopwatch will be reset to zero each time the Control button is pressed. In Jogularity mode the time split will be recorded but the stopwatch will continue recording. In Lap mode, the tabular display will reset the stopwatch to zero when the control button relabeled Lap Reset is touched and each split time will be identified as a Lap in the table. Also, in Lap mode, the options to zero either of the odometers are removed, however the lower odometer can be set to zero at the start of each lap by touching the Lap Reset button.

Note: Use of the GPS Twin Odometers during any particular rally will be subject to the rules and instructions governing the rally and may define your category or class among participants. Please consult the Rally Master for approval of the use of this app.

For better GPS reception and improved accuracy, third-party wireless GPS receivers are recommended. This app has been tested with Bluetooth connectivity to a Dual XGPS150A GPS Receiver. This app works with both iPhones and iPads, even those without Cellular connectivity. However, there can only be one Apple device with Bluetooth activated within range of the Dual Receiver. Place devices not running this app in Airplane mode and be sure that the Dual Receiver is connected with the device and app you are using. When Dual is connected to the app, the button in the top navigation bar will show "Dual" in green letters, otherwise, the button will show "Apple" in red letters. You may have to restart your Apple device and perhaps restart the Dual Receiver once or twice to get a successful connection.

Disclaimer: Continued use of GPS running in the background can dramatically decrease battery life.