Drip Irrigation Controller
The irrigation timer with advanced planning (ITAP) is a truly next-generation irrigation control system. Featuring a WIZnet WIZ810MJ network module and an Atmel ATmega168, the innovative controller directs user interaction into a standard web browser. As a result, the system doesn’t have a keyboard or LCD. The single-controller unit can manage up to eight zones. No software installation is required. Its functionality is split between the browser-based user interface and the hardware-based web server, data model, and control logic. The web server is used to read and write the internal data model. Its other function is to return files stored in internal program memory. Precision irrigation control is now a reality because the system provides useful information such as watering schedules and zone activity.
“My project is an irrigation timer that uses a web browser as its programming interface. Timers are simple devices, but their user interfaces are unreasonably complex. An Ethernet connection made it possible to correct this imbalance by using a remote browser in place of a local LCD and keypad. Once browser-connected, it was possible to add ‘what if’ planning tools that would be unthinkable on a stand-alone device. The hardware is simply an ATmega168, a ULN2803 driver chip, the WIZnet module, and not much else. I had been looking at various ways of adding browser support to a USB-based design. Previously, I had rejected Ethernet for either cost or complexity reasons. When the design contest introduced the WIZnet module, it was instantly clear that it would greatly simplify the design. With the WIZnet module, I could keep the parts count down and not waste scarce flash memory on networking code.”— Thomas Bereiter