Sports Radar is an iPhone / iPod application designed to capture the speed of a moving sports object. The application retains a history of previous speed readings and displays both the average and median values of the historical readings.
This application uses the time required travel a preset distance to determine object speed. The accuracy of this application is based on the reaction time of the user. Once the user presses the "Start Radar" button an internal timer begins. The timer ends when the user releases the same button. The object speed is then calculated by dividing the preset distance by the time elapsed between the user pressing and releasing the "Start Radar" button.
Accuracy - Explained
Since the application relies on human reaction time, it's important to use this application to capture multiple readings and base findings on the average and median values. Average is the sum of all historical readings divided by the total number of readings. Median is the mid-point value of the historical readings and as a result is not as sensitive to a small number of bad readings, also know as outliers. Below are two examples of Average and Median for 5 readings:
| Example | Reading 1 | Reading 2 | Reading 3 | Reading 4 | Reading 5 | Average | Median |
|---|---|---|---|---|---|---|---|
| #1 | 96 | 92 | 74 | 89 | 173 | 105 | 92 |
| #2 | 92 | 92 | 83 | 89 | 86 | 89 | 89 |
Notice Example #1 contained one reading almost double the other four. As a result the average was skewed. However the median represented a more accurate view of the speed readings as whole. The readings in Example #2 were more consistent and as a result the average and median values were the same.
How to use Sports Radar
- Set the distance the moving object will travel. This can be done using the distance slider or one of the three distance preset buttons. When the application starts, the initial distance is always that of the first (left most) button. The maximum slider distance and preset button distances are user configurable.
- When the object of interest starts to move press and hold down the "Start Radar" button. When the object reaches it's measure point (same as distance set in step #1), release the button.
- Check your speed display
- Repeat steps 1 thru 3 as many times as desired. Consult the average and median values for a more accurate representation of object speed.
Configuration Options
Sports Radar has the following configuration options. These are accessed using the standard iOS settings screen.
| Config Option | Description |
|---|---|
| Metric Units | If switched to ON, Distances will be represented as meters (m) and speed as kilometers per hour (kph) |
| Maximum Distance | Maximum distance that can be set using the main screen distance slider |
| Button #1 Distance | Value of main screen distance slider after pressing. NOTE: On application start-up, the main distance slider defaults to this value. |
| Button #2 Distance | Value of main screen distance slider after pressing |
| Button #3 Distance | Value of main screen distance slider after pressing |
| History Count | Number of readings to retain in history |
| Show Average | Display average value of all historical readings |
| Show Median | Display median value of all historical readings |
App Store Link
Requirements
- Requires iOS 5.0 or later
- Compatible with iPhone 3GS, iPhone 4, iPhone 4S, iPhone 5, iPod touch (3rd/4th/5th generation) and iPad
- Designed for iPhone 3GS, iPhone 4, iPhone 4S, iPhone 5, iPod touch (3rd/4th/5th generation)
