Summer Project Pays Off
Greetings to everyone.
This summer, Xavier, under the tutelage of Mom, Dad and a knowlegable fellow at the lawn and sprinkler supply store, has spent time building an automatic watering system for his garden.
Xavier got the bug to do more with the sprinklers in May when he and I had to debug why the sprinkler system stopped working. We dug up the valves, tested them and ended up having to replace the system's master valve.
We talked about some things, then decided to start by setting up an "above ground" system to automatically water his pumpkin patch on a daily basis. (his patch, this year, is surrounded by a ring of sunflowers, plantings from the birds eating from a nearby feeder this past winter).
Our initial prototype was a Y connection added to the sillcock to support both the use of a gardening hose and to supply the impact sprinkler.
Once those parts were purchased and in place, we focused on building a clock to control the valve connected to the other side of the Y. We chose (really Dad chose) to build the clock rather than buy one so Xavier could expand his growing understanding of programming.
We had an extra Raspberry Pi lying around (a Pi is a small, cell phone sized computer board). We ordered a relay block for the Pi to control and a weather-tight container to house the Pi.
When Xavier got the Pi wired into the relay block, we could now turn the valve on and off manually. We tested the system, and to Xavier's delight, his patch of pumpkins had water!
Manual on/off tested the system, but we wanted it automatic. We had planned a weekend away camping in early August, so the system had to be in place to take over the hand watering of the garden.
Thus, Xavier started the road to learning Python. With Dad sitting behind him and coaching, Xavier coded the turn on, wait while watering, turn off code. Sounds like a lot, but it was only about 15 lines of code.
The boy was sharp. As he copy and pasted the turn on code to make it the turn off code, he realized he needed to change a variable in the pasted code. That is a common source of bugs in the programming world. I was going to not say anything and then help walk him through debugging the system. He beat me to the punch and skipped the whole need to have a bug in the system. I was button-popping proud!
With the clock up and functional, we decided to build a full manifold for the system. Xavier likes mechanics and building things, so this sounded right up his alley.
Dad cut the PVC and instructed Xavier in how to glue the parts together. Xavier cemented a couple of parts in place. We took the valve off the Y connection at the sillcock and put in on the manifold. After a proper pressure test for leaks we had to tighten some fittings, but the cement work on the pipe joints proved sound.
Since we had four relays available for the Pi to control, we bought another valve and laid in a soaker hose into one of flower beds near the pumpkin patch. We were ready for the camping trip, secure in the knowledge everything would get watered while we were away. But, our secure feeling would soon get blown out of the water.
Rebecca and Xavier were on the front porch eating lunch. Xavier came into the house looking for me. "Dad," he cried. "We hear water!"
Sure enough, the connection from the Y to the manifold blew apart. We repaired it and walked away. A few days later, Xavier and I were out front and again we heard water. Again, the same connection blew apart.
Back to the sprinkler supply store for advise and parts. What we needed were clamps to secure the connections: two small WORM clamps. After two weeks of testing, our confidence in the system's integrity was restored. Now, only a few days before the camping trip, we felt the system would not let us down.
Indeed, it did not. We came home to a well-watered set of gardens, no wasted water and a sane water bill.
