At a Glance
Smart Measure - rangefinder1
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Smart Measure is an app that helps you to estimate the approximate--very approximate--distance and height of an object. It uses your phone's camera and accelerometer to triangulate the distance or height of an object, using some basic geometric equations. Hats off to the developer for creativity and innovation, but not for accuracy.
To begin, you need to calibrate the program and phone. If you haven't already calibrated your phone's accelerometer, you can do so in the application settings. To calibrate the program, you need to tell it at what height you'll be holding it when you use the app. You want to be as accurate as possible here. I used a measuring tape to measure up five feet from the ground--about the height of my collarbone. That was a good reference point for me, so I entered 5 feet into the program. If that doesn't sound incredibly intuitive, that's because it isn't.
Once you've entered the phone's height, hold the phone at that level and aim the camera at the base of an object some distance away. Aiming at the base is critical, because that's how the triangulation works. The app will calculate the approximate distance to the object. To save it, click the Get Distance button on the screen.
If you want to get the height of the object, hit the Height button, point the camera at the top of the object (while standing in the same place as before), and click Get Height. It will then save the height and distance on the screen. You can also use it to get the height of where you are standing in a building.
How well does it work? My results were mixed at best. Most of the time it was off by only a few feet. Sometimes it was off by 10 feet or more. For whatever reason, it seemed that the height results were generally more accurate than the distance ones, though I'm not sure how to account for that. Also, if you're not standing on a level surface with the object (that is, you're on a slope), that's going to throw it off.
This is not an app you could ever use for anything that requires precise measurement. Frankly, I have trouble imagining exactly what it could be used for other than answering the question "Hmm, I wonder very roughly how tall that thing is?" or for saying to your friends "Hey, check out this cool app!"