Wire Arc Additive Manufacturing (WAAM) is an emerging technology to produce metallic components thanks to its high deposition rate and low cost compared to other technologies. One step to make the WAAM technology reliable is to achieve a stable process control that can avoid collapse of the part during deposition caused by an excessive thermal input that may bring to a collapse of the part. To avoid that, dwells must be introduced in the production phase that slow down the productivity and introduce start-and-stop operations that often are sources of defects. This paper presents an easy-to-use and cost-effective monitoring system for WAAM as a first step to overcome this issue. The proposed technique uses an optical camera to acquire images of the deposited bead that are analysed to determine the condition of the bead itself to control the process. The general idea is to create the data background to support the implementation of a future closed loop control of WAAM, able to keep constant the deposition conditions and make the process stable. An experimental test case is presented to demonstrate that the proposed system is effectively able to monitor the process, extracting significative data form the acquired pictures that can be used to modify the process parameters to keep the deposition stable.