Internet of things (IoT) is a smart technology that connects anything anywhere at any time. Such ubiquitous nature of IoT is responsible for draining out energy from its resources. Therefore, the energy efficiency of IoT resources has emerged as a major research and development issue. In this talk, sharing an information on implementation effort of proposed Ultra low power, energy-efficient architecture for IoT, which consists of several layers, namely, sensing and control, information processing, and presentation. The architectural design allows the system to integrate energy harvesting/self-powered sensors, wireless power transfer, ultra-low power wireless communication, robust radio's etc. This mechanism allows the energy-efficient utilization of all the IoT resources. Our experimental & deployment results show a significant amount of energy saving, space utilisation, staff productivity, preventive & predictive maintenance in the case of sensor nodes and improved resource utilization of cloud resources. Also, outlining the challenges related to AI driven edge sensing & computing, data connectivity & privacy, AI data analytics, 3D data visualization, modelling and deployment of IoT applications and potential research directions in resolving these challenges.