EcoPops Solar Powered Automated Watering System

Michael Mobbs, from the nearby Sustainable House approached the university to help develop a free-standing solar-powered watering system for his new EcoPOP planter.

From his website: “An EcoPOP is a small, free-standing and self-sustaining green oasis. It catches and stores its own water from rainfall, powers itself with the sun's energy, generates its own nutrients, grows your own food, recycles materials, refreshes and cools cities, improves air quality, and builds better communities.

The team at the university offered to help Michael, and took on the design challenge at the Centre for Sustainable Energy Development. The team had already been experimenting with the open-source Arduino microcontroller, and thought it would be a worthwhile project for the tool.

Project Brief

The needs of the project

A robust and reliable automated water pumping system that runs on solar power, that can be programmed to provide irrigation to the plant bed when required. Sufficient energy storage to allow for many days of low solar radiation, with low standby power consumption.

The solution

A small DC water pump is used to provide a flow of up to 5 L/min, depending on back-pressure. The pump is energised from a small 12 V-7 Ah Lead-acid (or Lithium-ion) battery. The battery is charged from a small PV (solar) panel. An Arduino microcontroller is used to manage the pump, solenoid operation and energy supply.

Features and Capabilities

  • Programmable timer controlled pump and valve as the water delivery system
  • 5W, 12V solar battery charging system, with “off-the-shelf” low cost battery charge controller
  • Low battery voltage and low water level safety shutdowns
  • Real time clock for accurate pump operation without drift
  • Battery storage capable of powering system for 3 to 4 days whilst under low sunlight conditions
  • Built-in backup battery allows system to automatically recover on the day of good sunlight conditions if the main battery has been completely depleted due to an extended period of low sunlight conditions
  • Mini-USB connection point for operational configuration and data downloading via laptop
  • Can set up multiple daily alarms that trigger the pump if required
  • Pumping duration can be set anywhere between 1 second and 10 minutes
  • All pumping operations can be completely enabled/disabled via software control
  • Measurement and data logging of pump operation, PV output and battery state of charge (to micro SD card)

Future developmental work

  • Complete Bluetooth or wi-fi connectivity to provide easier programming and monitoring of battery state of charge.
  • Add soil moisture sensor and water tank level sensor

Project Acknowledgements

Dr Ian Laird (Sydney University) for initial code and hardware prototyping
Dr Rob Helstroom (retired) for refining and extending the code to include calibration, data logging and improved program flexibility, and for improvements in the pump driver circuits.
Mr Sarkis Keshishian for building the prototypes, testing and installation.
Michael Mobbs for the design and supply of the ecoPOP, currently located in the Sydney University Engineering Precinct between the School of Chemical and Biomolecular Engineering Building (J01) and the Peter Nicol Russel Building (J02).

For more information including copies of the design, and arduino code are available for further development. Contact Tony Vassallo of the Centre.

EcoPOP unit at the School

The mini ecoPOP outside the School of Chemical & Biomolecular Engineering

The EcoPOP pump and control unit

The pump and control unit is housed in a plastic container under the bed