Re-using old cellphones for IoT applications

In today's world smartphones are the most used electronic devices as they come with many capabilities that makes everyday life easier. Because of the increasing rate in the smartphone market consumers are always getting new and up-to-date devices, this means many people end up with second-hand smartphones at their disposal that they don't use. On this paper we show one way on how these smartphones can be re-used for IoT applications. Most sensors are low powered and use Bluetooth for connectivity and for that reason it becomes difficult to store and view data they collect on the web. On the solution a second-hand smartphone is used as a gateway for the sensors in a wireless network system to allow them to have memory and web capabilities. A case study of how the network system can be used in a household is presented on the paper.