The W-MON project aims to improve and automatize the control of the presence of radioactive material in conventional waste containers at CERN using a distributed network of interconnected low-power radiation sensors. The key development is the integration of a lightweight but sensitive radiation sensor in a powerful network that allows continuous data recording, transfer and storage in a database for alarm triggering and subsequent data analysis. The Chiyoda D-shuttle personal dosimeter was used as proof-of-concept. Extensive tests performed with the commercial version of the D-shuttle showed that its robustness, stability under variable thermal conditions, high sensitivity and hourly dose logging capabilities make it a strong candidate for the project. To comply with the requirements of remote operation and wireless data transmission to a central server, a customized version of the D-shuttle has been developed. Two additional radiation sensors are also currently being considered. The sensors have been coupled to a custom-made communication board allowing for long-range low-power LoRa wireless data transmission. A centralized IoT (Internet of Things) end-to-end data architecture has been developed for real-time monitoring and visualization of the radiation level in waste containers before the final integration into REMUS, the overall CERN Radiation and Environment Monitoring Unified Supervision service. •Environmental radiological monitoring for conventional waste.•Lightweight and smart radiation sensors for real-time monitoring of the radiation level in waste containers.•Distributed network of interconnected low-power radiation sensors with LoRa wireless data transmission.