Embedded Lab

Snellen chart is the most widely used visual chart across the globe for testing visual acuity. It contains multiple rows of letters that are progressively smaller and is used by an eye doctor to judge patient’s eyesight. Joel Llewelyn, Margot Haas, and Yuchen Liu (three Cornell students) attempted to make an electronic version of Snellen chart that is portable and self-capable of performing the full Snellen eye test at home. The project uses PIC32 microcontroller and a TFT display for showing the letters from the Snellen chart in a progressively smaller font size and the user has to speak over a microphone his guess for the letters. The user’s audio captured by the microphone is amplified using an Opamp circuit and is further digitized for speech processing by the PIC32 microcontroller. Their electronic Snellen eye tester utilizes a speech recognition thread to determine if the user’s guess is correct or not.