Low-Cost Sensor for Determining the Deflection in Timber Beams

Abstract

The static loads and dynamic actions that structures withstand throughout their useful life have repercussions on their durability, causing deformation of the materials of which they are composed and jeopardising their stability and the integrity of the people who inhabit the buildings. For this reason, the development of measuring equipment to control the deformations suffered by horizontal beams and frameworks is very useful for the construction sector. In this work, a measurement system has been developed through the construction of a low-cost sensor composed of two stages: a stage sensitive to the deformations that occur in strain gauges configured in a Wheatstone bridge, and another amplifying stage that allows an easily interpretable and measurable signal to be obtained. The sensor has been tested by measuring the deformation that occurs in sawn timber beams subjected to a simple bending test under point load. The results show how the implemented low-cost sensor allows to obtain a linear voltage response in relation to the induced deflection in the centre span of the beams. These results allow us to infer the potential application of the device in the building sector, incorporating it in media equipment that allows real-time monitoring of the state of deformation in structural elements and the appearance of cracks and fissures.