Design and implementation of a low cost modular sensor

On the financial side, a key factor for the success of a smart-city initiative is the low cost of the sensors. On the technical side, the units need to be flexible enough to cover different roles, and to be reconfigurable for a distinct target. The capability to interact with an already deployed infrastructure, like a preexistent web-server, is a favorable feature from both the financial and technical point of view. In this paper we exploit an overlooked feature of the ESP8266 WiFi chip, i.e. the AT commands interpreter, to implement a sensor/actuator that meets the above specifications. To test our design, we implement a library that provides a transparent wrapper for AT commands. Using a prototype consisting of a board hosting an ESP01 coupled with an Arduino Nano, of which the cost is around 10 Euros, we evaluate the static properties and the operational stability.