Ruling Ruler

Splash screen
Initial interface (uncalibrated)
After calibration
After pressing the calculate button to measure the length of copy paper
Instructions

Inspiration

Our team of Brown and RISD students was brought together by a passion for convenience. These days there's an app on your phone that can replace carrying objects from cameras to GPS devices. Our app replaces the need to carry a ruler, because let's be honest -- does anyone really carry a ruler around anymore?

What it does

We created the Ruling Ruler, an app that measures the length of any object that the camera points to, according to the angle formed between the object and the phone. Begin with the phone flat on a surface, and after it is calibrated, the user rotates the phone upwards using the bottom of the phone as the vertex. Once the edge of the object is at the crosshairs/target, the user can tap calculate to get the calculated length of the object. The angle will also remain on the screen for any further use, and the user can press the button again to recalibrate and calculate the length of another object.

How we built it

We used Swift in XCode for coding the application, and Adobe Illustrator for the graphics.

Challenges we ran into

Initially, we had planned to measure objects through tracking the acceleration of the phone in one plane, so that the user can move the phone forward and backward on the plane of the screen, but we realized that the accelerometer accumulates to many errors over time for the measurement to be even mildly close to the real length of the object. Because of this hardware limitation, we completely changed our approach to creating a ruler application and used the gyroscope data instead.

Accomplishments that we're proud of

As a team of all first time hackers, we're proud that we learned Swift from scratch and that we were able to make our first iOS app in less than 24 hours! Additionally, we're happy that the motion from the calibration angle works properly and is very sensitive. Best of all, the app is actually fairly accurate with about a 1 cm margin of error!

What we learned

As mentioned, we learned and have a basic understanding of coding in Swift and using XCode! We also learned that an app can be built in as little as 10 hours with lots of dedication, caffeine, and snacks!

What's next for Ruling Ruler

Given more time, we will develop our app to be able to detect rotation along different axes so that the user can also calibrate the angle by holding the phone to a wall and rotating it off the wall (parallel to the ground). We also want to include more options within the app to allow users to change the units of length and to have a simple instructions screen so the app is easier to understand. Our ultimate goal is to come up with an algorithm using the motion data in the phone that allows users to measure the length of curved objects too.