Fingertip laser light sensor

Original assignment

I will provide you with a laser that emits a sheet of laser light and a sensor that detects this light. You will investigate their use in developing a fingertip position sensor that senses distance to the finger based on reflected laser light. Your job is to design a sensor circuit and determine the analog voltage readings you get as a function of (1) your finger position and (2) the sensor's location relative to the emitter.