Industrial Technology Research Institute (ITRI) has worked for a long time to iron out all issues around the energy efficiency, durability, product yield rate and cost of dye-sensitized cells (DSC), a replacement for battery power sources in indoor applications. Their efforts have brought about a production facility capable of producing 2700 m2 (120,000 pieces) of DSC per year. As a result, a wireless and environmentally friendly power source, DSC as Energy source Of Sensors (D-EOS) is now at your fingertips. Moreover, it can be made with decorative colors. With the Internet of Things (IoT) era, DSC is going to be more and more popular in supporting smart homes, smart offices and even smart factories. By combining its low-illuminance power-generating capability with wireless transferring module and rechargeable batteries, D-EOS can be conveniently integrated with various in-door sensors (the building block of smart buildings), eliminating the problem caused by changing large quantities of batteries and thus reducing environmental issues like battery disposal or land poisoning.