Fabrication of an Economical Arduino-Based Uniaxial Tensile Tester

The mechanical properties of soft materials are critically important for a wide range of applications ranging from packaging to biomedical purposes. We have constructed a simple mechanical testing apparatus using off-the-shelf materials and open-source software for a total cost of less than $100. The device consists of a wooden frame supporting a central loading apparatus attached via drawer slides. To perform a mechanical test, a sample is secured within two custom-made 3D-printed clamps affixed to brackets on the base of the frame and the load cell. The extension force is applied by the user pulling on a rope, moving the central loading apparatus up (thereby stretching the sample) while recording the force (measured by a load cell) and the displacement (measured by an ultrasonic sensor). The load cell and ultrasonic sensor are linked to an Arduino microcontroller connected to a laptop through a USB port for data acquisition and analysis. This instrument was easy to assemble and enabled students to bette...