Maker upgrades his sprinkler controller by integrating it with his Monteino home automation gateway.
It seems like everyone across the U.S. is experiencing a drought these days. So when it comes to conserving water, an older sprinkler system may not be the most efficient in doing the job. Cognizant of this, Felix Rusu decided to channel his inner Maker and to upgrade his unit by integrating the outdated irrigation controller with his home automation gateway. This, of course, enabled him to define his own schedule and control it wirelessly from his smartphone, among a few other things.
“I took apart the sprinkler controller to figure out how it works. There are two boards, one hosts the 24VAC TRIACs and circuitry that powers the solenoids. The other was a controller board with user interface, LCD, buttons etc. This gets power from the first board and controls the TRIACs through a ribbon cable. A quick continuity test reveals the pins of the ribbon connector control the gates of the TRIACs, simple enough,” the Maker explains.
At the heart of it all lies a Moteino (ATmega328). To interface it with the sprinkler system, Rusu first had to create a PCB interface. This board, which he calls the IOShield, features a buck power supply that regulates the 24VAC power of the sprinkler down to 5VDC for the MCU and two 74HC595 shift registers. The output from the shift registers are connected to a pin header where the stock computer would normally have been plugged in. It should also be noted that the IOShield is daisy-chainable and features 16 channels along with 16 indicator LEDs.
“I have nine sprinkler zones, but one IOShield will support up to 16 outputs. I can use the TRIAC board and only tap into the nine zones that are active,” Rusu writes. “I can just use the first board with all the TRIACs and then replace the clunky standalone sprinkler controller board with the IOShield+Moteino combo for completely wireless control and integration to the gateway.”
With some programming and an accompanying mobile app, the new board is able to take over the sprinkler’s TRIACs, enabling him to turn on and off the zones with a touch of a finger. Intrigued? You can read all about the Maker’s project here, or listen to his detailed overview below.