Want the very best from your garden? You need to make sure they get sufficient water to stay healthy. But who will take care of them when you go away for vacations? Dimbit came up with an idea to solve this problem. He decided to build his own solar powered circuit that would automatically take care of his plants. There are more one ways of tackling this issue. Dimbit wanted to make a unique design that would consume very little energy.
Dimbit first considered the power supply. His project wouldn’t consume more than 5V of the power supply. He incorporated four off-the-shelf solar garden lamps in designing his own power supply. Each of these lamps contains a crap solar panel and a AAA NIMH cell. He figured that a custom stand would give a god look, so he created a plastic stand and 3D printed this too. All of the cells and the AAAs are connected in series to get more voltage.
Dimbit was looking for a water valve that could be controlled electronically and consume not much more than an Amp. He did a lot to find one but found nothing readily available. He tried with all sorts of things but couldn’t make something with a perfect seal. Suddenly he was stuck with a strange idea.
One day, when Dimbit ran out of dish washing detergent, he spotted that the cap on the detergent bottle had a perfectly made torodial hole that should be sealable with a steel ball bearing. He crafted his own electromagnet using a bolt, some magnet wire and a custom 3D printed housing. All these were perfectly assembled within the detergent cap to make a functional low power water valve.
The actual circuit is powered by a Microchip PIC microcontroller. The circuit is programmed to sleep for approximately nine minutes at a time. At the end of the sleep cycle, it becomes active and tests a probe that sits in the soil. If the PIC detects that the resistance is low then it unlocks the custom valve to release about two teaspoons of water from a gravity-fed system. Following repeated cycles, even very dry soil can reach the required moisture level.
Watch how the system works in the video below.
Via: Hacked Gadgets