A number of MIT students have equipped a Macbook with a rudimentary touchscreen by using a small mirror, which is placed in a corner in front of the webcam. They have also published the accompanying software.
The adjustment would cost about a dollar, according to students Anish Athalye, Kevin Kwok, Guillermo Webster and Logan Engstrom. Their project, called Project Sistine and the result of 16 hours of work, uses the reflection of the mirrored Macbook screen. By placing a mirror at the correct angle, their software can use the built-in webcam to determine the position of the finger and ‘see’ if it is touching the screen. The students have published a video.
They released the code for their ‘hacky’ finger detection algorithm on GitHub. To use it, you must first go through a calibration process to create a projection matrix for screen coordinates. In their prototype, the students convert their touches into mouse movements, allowing them to draw shapes or scroll, for example. A higher-resolution webcam and a curved mirror for capturing the entire screen would lead to better results, they say.
The mirror for the webcam