A Low-Cost Wireless Interface Linking a Microcontroller to a Microcomputer Server

The development of a low-cost solution for the connection of wireless sensor nodes to the Internet is presented. The solution has the additional benefit of extremely low power consumption and hence very long battery life and low maintenance cost. The core of the solution is the Atmel ATtiny series of wireless transceivers and the designs of minimised printed circuit boards for three versions of the node are presented. To provide the fixed node at minimum cost, the Raspberry Pi microcomputer was used, attached to the Nordic Semiconductor nRF24L01+ transceiver module. Software to implement the system in each of the nodes was developed from zero-cost sources, the software being tailored for the particular application and devices selected. A World Wide Web interface for the Raspberry Pi was created, having an intuitive display and offering functionalities relevant for general automation tasks, data display and manual control, in conjunction with wirelessly connected clients. The Web interface can serve as the basis for a home automation system, a topic which is becoming more and more important and popular nowadays, but industrial applications are equally feasible.