A tennis pro’s serve can hit 70 meters per second. A baseball pitcher’s fastball can top 90 miles per hour. Football strikers go for the goal in excess of 100 kilometres per hour. How fast are you? Speedhero knows.

Speedhero is an app that turns your Nokia mobile device into a sports speed detector. Using proprietary signal processing and algorithms, Speedhero ‘hears’ when you strike or kick a ball, measures how long it takes for the ball to hit a wall, fence or other hard surface, and then calculates and displays the ball’s top speed.

Speedhero can measure your top speed for over a dozen sports, including football (U.S. soccer), American football, baseball, ice hockey, cricket, golf, tennis, and rugby.

Because the app uses sound recognition, you can also adjust its sensitivity for different acoustics – less sensitive for loud spaces (like a city street), more sensitive for a quiet area or sport. When set properly, the app is said by its publisher to be accurate to within 1 millisecond, with a margin of error not exceeding plus-or-minus 2 per cent.

Social networking is available, too. Entetrainer Ltd., the publisher of Speedhero, runs a website where Speedhero users can record their top speeds, view the top speeds of others, and share their results on Facebook.

In my test, I found Speedhero straightforward to use, though it did take a bit of preparation. In addition to my Nokia device, I needed a ball to kick; a location with a wall or other hard surface that would produce a sound when hit by my ball; and a tape measure.

Once I had all that together and was at my location, I fired up Speedhero on my Nokia N97 device and told it which sport I was playing – in my case, football (US soccer). Then, using my tape measure, I measured the distance between my shooting spot and a wall. I set my kicking distance at 21 feet (6 meters). Because I was using the app without an assistant, I found I needed to set the radar timer for 9 seconds – enough time to get the app going, run back to my position, set up the ball, and kick it. Also, because I was using the app outdoors in my noisy city neighbourhood, I set the sensitivity level to Low. Finally, I placed my Nokia device on the ground halfway between the shooting spot and the wall.

Here’s an artist’s rendering of the essential setup, courtesy of Entetrainer:

What happened next was pretty cool. First, Speedhero whistles to let you know it is ready. Then, using the microphone in my Nokia device, Speedhero ‘heard’ when I kicked the ball, then tracked how much time passed before my kicked ball hit the wall. Finally, the app used my Nokia device’s processing power to calculate the ball’s top speed.

My results? Well, let’s just say that the great Brazilian goalkeeper, Júlio César, has nothing to worry about! My top speed was a pathetic 47 miles per hour (approximately 75 kilometres per hour). While that was the fastest of my several kicks, it was enough for Speedhero to give me a roaring cheer!

I also found Speedhero easy to set up, thanks in part to its publisher’s participation in a Forum Nokia user experience (UX) evaluation. The app was first evaluated by a Forum Nokia usability expert, who identified several issues: the need to make the app’s instructions more visible, clarifying the initial screen, and automatically locking the ‘power saving’ mode while the app is being run. Next, Speedhero was evaluated by several test users in a usability lab environment. As a result of the two UX evaluations, Speedhero was improved and streamlined. You can learn more about Speedhero’s UX evaluation in this mini case study.

Speedhero runs on Nokia Series 40 and Symbian OS, S60 3.x and 5.0 devices alike. However, it works somewhat differently on each platform, according to Entetrainer. On Nokia’s Java-based Series 40 devices, Speedhero uses audio loops. But on Symbian OS, S60 devices, the measuring takes place directly via the audio stream.

Either way, Speedhero Lite is available for free in Ovi Store.

I was unable to capture screenshots of Speedhero. But you can watch several videos of the app in action on Speedhero’s dedicated YouTube TV channel. You can also read another review of Speedhero, posted on  Ovi Daily App earlier this year, here.