Wireless sensors form an integral part of the Internet of Things (IoT), standing at the edge between the cyber and physical domains. Ac-quiring and transmitting environmental data is an energy-intensive workload, especially when considering networks spanning large buildings or even cities. Many works aim to integrate energy har-vesting into wireless sensors, providing them with a greater level of energy autonomy. Initially deployed for energy-rich outdoor environments, recent advances have allowed wireless sensors to efficiently utilize the reduced energy harvested in indoor lighting conditions. This demo introduces a harvesting-based Dual Proces-sor Platform, the DPP3e, designed for energy harvesting in indoor environments. It features various sensors for advanced indoor en-vironmental sensing, e.g. air quality measurements, a low-power display for immediate visual feedback, and a powerful micro controller for energy-efficient inference of Tensorflow models. Fur-thermore, it has two separate RF interfaces: a 2.4 GHz Bluetooth Low Energy (BLE) radio for short-range communication, and a sub-GHz transceiver for long-range communication. Using configurable power domains and advanced power management, it can sustain sending BLE packets every 5 seconds while consuming only 37 µ W.