The Smartest “Dumb” Sprinkler on the Block!

Options Galore

There’s no shortage of smart sprinklers available—internet connected, Bluetooth enabled, learning, weather forecasting marvels! They save water and for many they are probably just right. 

But most are expensive, can be challenging to configure, may require an ongoing subscription, and might even collect your data!

The Free (and Fun!) Option

Moreover, I already have a sprinkler controller that works! It's just a difficult to use timer, but with plenty of tinkering it gets the job done.

And importantly for this endeavor, it has a spot for you to wire in a Rain Sensor! They overpriced switches allow disabling scheduled waterings when recent rainfall is detected. I believe they are sold largely to meet regulations, are seemingly rarely functioning (case in point, my HOA sprinklers run in the rain despite having a sensor "installed"), and are at best reactive. Plus, my controller was in my basement so Rain Sensor installation would require drilling a hole in my house...

Instead of a Rain Sensor, I devised to plug in an internet enabled, programmable switch that could see the future! By wiring in a relay controlled by a Raspberry Pi, I could programmatically disable the sprinklers on my command!

 

The Build

Fortunately I have a pile of Raspberry Pi's and Qwiic accessories laying around. I chose a Pi over an Arduino or similar for the full: OS, VNC, SSH, SystemD, etc., which would allow me to manage things without having to venture to the basement to reprogram anything. It would also leave me plenty of headroom for future projects, e.g. disabling sprinklers through HomeKit!

I chose DarkSky Weather API because it was reliable and free, but it has since been purchased by Apple who has announced they will soon only support weather with a current Developer Account ($). I'm looking around for alternatives.

A Raspberry Pi Zero W 2, Python and and some Qwiic modules from Sparkfun made the whole thing painless. 

Lots of details and code can be found on GitHub: Sprinkler Pi Sense

"Real" Spinach & Arugula - Aero Garden

"Real" Spinach & Arugula

Part 2 - The Grow

New Problems

1. Root Sensitivity

• I knew spinach, arugula and the like don't transplant well and are recommended started in the ground, but regardless of technique, all plants experienced some stress and shock on moving to the aero 

• I ended up using two site for starting seeds right in the aero and two sites for mature plants. The plants grow so vigorously there wasn't room for four full grown plants anyhow
  

2. Poor Choices?

• Rocky (Diplotaxis tenuifolia)

•  Has turned out to be sloooooooooooooooooooow growing. In picture below, the tiny plant closest is Rocky, which was started at the same time as the spinach (back) and Astros (left and right)
  

• Spinach and arugula preferences

• Arugula wants lots more ammonium than spinach, and making one happy caused the other issues
  

• Bad sensors
  

• I had a SparkFun Environmental Combo Breakout - CCS811/BME280 sensor that came with the Qwiic kit, but as other note, the CO2 sensor heater throws off the humidity and temperature
  

• Bad sensor preparation
  

• I fried my initial Qwiic SCD41 CO₂ Humidity and Temperature Sensor when it got wet! This was easily fixed with a liberal application of silicone conformal coating on it's replacement
  

 Successes 

1. Astro is incredibly fast and large yielding, and seems to never bolt!

• I've started growing four Astro. It lacking in variety, but each plant yields a small salad each week, sprout in days, and mature in about two weeks
  

2. Lots of delicious Rocky flowers!
   

• While very slow growing, it was quick to bolt and produced spicy delicious flowers for a two weeks

3. ESP32 Thing Plus, Qwiic accessories, and Cayenne made monitoring a breeze

   • More below!
     

Aeroponic Sensor Upgrade 

The Arduino Wifi Rev2 was good enough for temperature monitoring but lacked Qwiic and was large..

Enter the ESP32 Thing Plus! Small, efficient WiFi and Qwiic enabled module from SparkFun!

Full details and example code on my GitHub 

 

Up Next: The Garden

It's spring! Time to take my grow experiments to the backyard!!

"Real" Spinach & Arugula - The Plan

"Real" Spinach & Arugula

Part 1 - The Setup

The Problem

We're spoiled with dark, rich, fully savoyed spinaches and spicy, nutty, deeply lobbed arugulas from our organic, biodynamic Aspen Moon farm-share, except in winter!

The smooth, mild spinach and lettuces we're able to get get at the grocery left me wondering if I could grow better in my closet?!

The Plants 

I decided to start seeds in 9 cubes and would select the best 4 at the end of germination.

• Bloomdale (Spinacia oleracea)
•  Heirloom from 1826! High in vitamins A and C, and iron!
  
• Rocky (Diplotaxis tenuifolia)
•  Fast growing, wild-type heirloom. Complex and nutty flavor.
  
• Astro (Eruca vesicaria)
  
•  Peppery. High-yield! 
  

While I'm at, I'm going to start some microgreens in coconut coir!

(Will add germinated photo!)

The Aeroponic Setup

For simplicity and (hopefully) fast, high yield I opted to create a small low pressure aeroponic (LPA) bucket. These are often used for cloning but it works equally well from seed.

5 gallon bucket; 2" holes, baskets, collars, and rockwool cubes

Submersible pump; 1/2" vinyl tubing/tee + 180 degree sprayers; airstone/pump

The Aeroponic Test!

Before adding plants I ran the system for several days to verify setup and tune schedule.

Cheap Cycle Timer to manage continuous spray schedule

There are lots of opinions on the optimal schedule for your LPA but the main issue I was worried about was water temp! The submersible pump generates a lot of heat while pumping and bucket and carpet I intend to run on offer plenty of insulation...

I setup a simple sensor to allow monitoring the temp. This will be useful now and when the system is in use. Details can be found on GitHub here: Ardruino Uno WiFi Rev2 Cayenne Water Sensor

Continuously running pump for three hours, and cool down

A bit of testing revealed 3min on and 13min off could be run continuously without heating the water and nutrients.

Up Next: The Grow!