Low-cost Ultrasonic Probe to Assess Wood Defects and Parameters

Wood is a natural material that due to its properties has been used for years in many applications such as construction and furniture industries. Being a natural material it is prone to defects which must be detected, preferably during the early stage of product production. Testing of wood pieces, to detect defects or to determine some of its properties, can be made using two types of techniques: destructive and nondestructive. For obvious reasons Non-Destructive Testing (NDT) is more desirable because pieces subject to testing do not suffer any change of its structure. One of the techniques that has been used in such tests is based on ultrasonic waves. In this paper it is presented a low cost ultrasonic probe that can be used to detect some defects on wood pieces. It is based on an FPGA which allows the development of a system with the performance of hardware based systems and flexibility of software based systems. The prototype was then tested successfully to detect some defects and to determine the dynamic module of elasticity (Ed) of wood samples. The obtained Ed values were compared with values obtained using mechanical testing.