We have constructed an operational, educational model of an atomic force microscope which employs and highlights the fundamental concepts and principles involved in nanoscale microscopy. The probe, which holds the laser source and the cantilever tip, is mounted on a carriage which moves in the horizontal x-y plane. The translation in the x-direction is obtained using a screw system, while y-direction movement is governed by two sets of rack and pinion gear systems. Off-the-shelf optical rotary encoders provide horizontal position transduction while vertical deflection of the cantilever tip on the sample surface is achieved by a pen-laser-based dual photodetector system. The hardware and electronics required to build the entire device may be purchased for less than $1,000 making it ideal for K-12 teachers trying to demonstrate the fundamentals of nanoscience to their students. This project also includes an instruction manual for building the device which is available on the author’s website
