In recent years, the use of timber in construction has significantly increased, driven by global decarbonization targets and advancements in engineered wood products. As a result, concerns about the durability and long-term performance of new timber buildings are becoming increasingly prominent. Monitoring wood moisture content is a critical aspect of addressing these concerns, as it directly influences wood’s susceptibility to biological degradation and its physical and mechanical properties. Despite the availability of various wood moisture meters on the market, these devices are often costly or involve ongoing subscription fees, limiting their accessibility to researchers and practitioners. This study introduces an Arduino-based, low-cost wood moisture content data logger as a viable alternative. Leveraging the customizability of Arduino, an open-source platform, this device enables users to modify their measurement setups to suit specific research needs using a range of compatible sensors. The system utilizes the electrical resistance method to measure wood moisture content. The paper provides detailed information about the components used, including the Arduino board and sensors, the electronic setup, and the open-source code developed for the device. Additionally, an experimental campaign was conducted to validate the system’s performance by comparing its results with those of two commercially available wood moisture meters and one digital multimeter. The validation involved monitoring wood samples with varying moisture levels under controlled conditions to evaluate accuracy and reliability. Results demonstrate that the proposed system provides comparable accuracy to commercial solutions while maintaining a fraction of the cost. This approach empowers researchers to construct their own customizable, cost-effective wood moisture content data loggers, broadening access to critical tools for wood property analysis and degradation monitoring.