Our large-scale, educational AFM consists of a small-power laser, LEGO® bricks and a LEGO® Mindstorms controller, allowing students to build the cantilever tower, scanning stage and light sensor tower roughly in one hour. Once complete, the sample surfaces that come with the kit are ready to be scanned. A LEGO® Mindstorms kit is also integrated to automate the control of the sample stage and sensing of the laser beam for the monitoring of the cantilever deflection. Two Mindstorm motors move the stage in x- and y-directions that the cantilever tip is able to scan the entire surface and students can watch the AFM in action. Similar to a real AFM, the cantilever deflection is measured using a laser spot reflected from the top surface of the cantilever, but its detection is through vertically aligned Mindstorm light sensors as an alternative of the photodiode array.
To interface the LEGO® AFM with a computer and display the scanned image in real time, we have developed operation software using Labview. As the LEGO® AFM scans the sample, the software displays the corresponding contour plots in real time with different speeds and resolutions. Thus students can understand the working mechanisms of the AFM by building and operating the LEGO® AFM by themselves and learn how operational parameters affect the overall quality of scanned images.
With the development of the LEGO® AFM kit, we hope to more expose nanotechnology, particularly nanoscale imaging and instrumentation technology, to young students and inspire them to pursue STEM careers. Moreover, this kit is anticipated to ease the understanding of the physics behind the AFM for beginning AFM users and trainees, as the real AFM is often too small and compact to directly see and understand its working mechanism.
This outreach project is being supported by the National Science Foundation (CBET-1067441).