Dynamic DIY duo builds hybrid energy harvesting project


At TI, we celebrate the makers and hobbyists who enjoy creating and innovating on their own time. In our ongoing DIY with TI series, we share their incredible Do It Yourself inventions using TI technology.

TI AvatarTwo of our favorite do-it-yourselfers, Will Cooper and Dave Smith, have joined forces to create a hybrid DIY project that might just be the envy of every gardener.

Will and Dave, who are both MSP microcontroller (MCU) experts, have teamed up to build a high-tech energy harvesting/plant-watering system based on our MCUs. They found a way to remotely water a garden of chili peppers, bell peppers, jalapenos and herbs using a kit of solar panels, moisture sensors, a battery, pump and timer.

The system stems from Dave’s popular “Chili-gation” project, which blended his love of gardening, creativity and MSP know-how to build an automated chili plant watering system.

“When my chili plants are in pots, they dry out during the day in the Texas heat. With this system, I am able to keep the plants alive if I go away for a weekend,” he said.

The heat is on

Chili-gation was a hot hit at last year’s “DIY with TI” event, where Dave shared samples of his habanero-based salsa with visitors. At the same event, Will displayed a wireless controller that can remotely turn lamps on and off so it looks like a house is occupied when nobody is home. Read more about Will and his innovative projects.

This year, Will and Dave wanted to turn things up a notch with their new hybrid project.

“We had an automated system in place but wanted to make it useable in a remote area, such as a home garden, without the need for battery replacement,” Will said, adding, “Now, the battery pack is charged just from the ambient light.”TI Avatar

Here’s how the system works:

The battery-powered, MSP430™-based system uses an MSP430FR5969 ultra-low-power MCU, BQ25570 ultra-low-power harvester integrated circuit (IC) and DRV8838 low-voltage DC motor driver. It also uses small solar panels and a pump that Dave bought from Digi-Key Electronics, a TI distribution partner. All of the components and plants are contained in a wooden box that Will built.

The MSP MCU handles the system control, timers and system display and also analyzes the moisture sensor inputs. The harvester IC enables the connection of the solar panels to charge the battery, and the motor driver turns on the water pump.

The project is designed to harvest energy for sustained use. It’s programmed to water the garden on a timer or use a soil moisture sensor that turns the pump on when needed.

“We added an option to shift between a timer or moisture sensor to start the watering,” Dave said. “You can run the pump for longer, but then it will use more energy. It could be scalable for different-sized gardens.”

You could build a number of projects using the basic components of the project, such as an automated pet feeder or a robotic tool that operates on a timer. Click here for instructions on how to build your own automated plant irrigation system with TI parts.

The dynamic duo will show their new hybrid energy harvesting/plant-watering system at the fourth-annual DIY event on Wednesday, April 13. DIY events will take place around the world that day in the United States, China, India and Germany.

Made for the movies

Dave and Will said they were somewhat inspired by the blockbuster movie, The Martian, in which the lead character used energy harvesting to water and grow a crop of potatoes on Mars.

“We did this after seeing the way the movie showcased energy harvesting to run systems perpetually,” Will said. “Our power required is significantly less than what you see in the movie. We can run our system off solar panels that fit in the palm of your hand.

“Plus, we live on earth, so we don’t need to make our own water.”