Use Raspberry Pi to Control Your Garden Sprinklers

People who have a lawn in their backyard know how important it is to water it carefully to keep it looking green and lush. The timing has to be right to prevent the grass in the lawn from drying off and allow just enough water so that the lawn is not flooded. Most people use sprinklers to wet the lawn evenly. However, timers sold in the retail stores for controlling the sprinklers have only limited functionality that leaves users unsatisfied.

Most people are busy and on the move, which does not allow them much time to monitor the working of the sprinklers. With the timers purchased off the shelf, it is not possible to have flexible watering schedules and remote control is not a feature.

This unsatisfactory scenario of the uncontrollable lawn sprinklers led Ray Wang to set about designing his own sprinkler controller. He built his first functioning prototype “The Mint-tin Water Valve Controller.” It used an Arduino Pro Mini and a homemade PCB with a wireless transceiver. Along with Chris Anderson, the editor-in-chief of Wired magazine and the CEO of 3DRobotics, he turned this project into a potential business opportunity. It grew into an open-source, web-based smart sprinkler controller project – the OpenSprinkler.

For Ray, keeping OpenSprinkler as an open-source project is important, as he is an educator who always wants people to not only use a product, but also to have the opportunity to learn how the product works internally. The project has a strong educational purpose, as anyone can design a new sprinkler based on this project and not have to reinvent the wheel, a great way of promoting technological innovations.

Starting with OpenSprinkler v1.0, Ray improved it to v2.1 before moving over to the affordable, tiny credit card sized single board computer, the Raspberry Pi (RBPi). The advantage is that the RBPi’s GPIO pins can directly control the sprinkler valves. Thus, on Feb18, 2013, was born the OSPi or OpenSprinkler Pi v1.0.

A number of enthusiastic users helped in porting the Arduino code to Python for use with the OSPi. In the process, they introduced new features such as advanced logging and a built-in mobile frontend. Others revamped the code and provided a more modern, streamlined user interface. Ray has made a pre-configured SD card image where the OpenSprinkler software is pre-installed. If you need to control your lawn sprinklers, all you need to do is download this image, burn it into an SD card and pop it into your RBPi. Of course, you will need the sprinkler extension board, which houses all the hardware necessary for making the project compatible with the standard 24VAC sprinkler valves used for watering and irrigation systems.

OSPi makes the entire project much more convenient and intuitive compared to traditional sprinkler controllers that have buttons to set everything and a tiny LCD, which hardly helps. OSPi is a web-based controller that allows remote access. The user can additionally pull in weather data online for helping to adjust watering schedules when necessary.