This project started when we installed a new lawn and found myself needing to diligently water the new grass but not having the time to constantly be moving hoses twice a day. Any IOT hose timers I found were either expensive or had horrible reviews. Wondering if I could hack a dumb timer I found this four valve Melnor digital water timer at Lowe's for relatively cheap (~$45). What caught my eye was that the four valves are separate from the timer controller and connected by a cable with plug on the end. The cable is prime connection point for a hack so I purchased two and began a tear down of one.
I'm going to document my findings and hacking attempts here. My end goal is to use a Wemos D1 Pro Mini (ESP8266) to be able to control/schedule the valve over MQTT and be able to have it not run when it rains or the ground is still wet.
Details
The Melnor Digital Water Timer can be found here: LINK
The valve assembly is controlled by a wire that has 7 pins. Initial attempt at measuring activity with a voltmeter resulted in frying the control unit, I must have shorted two pins. So I will have the control unit replaced and next will use the logic analyzer instead of "running" a voltmeter probe across the pins.
https://hackaday.io/project/171942-two-zone-wifi-water-timer