Day 66: Relay Board Hookups

Monday, 30 November 2015


Above is the DC Relay Board from Vegetronix. Four freshmen with little to no electronics experience figured out how to wire it up to a 9 volt battery, a Vegetronix soil moisture probe, and a sprinkler valve. They tested it with a jar of soil as shown below.

Day 65: Soil Moisture Lab

Friday, 20 November 2015



Today, a one-sentence lab: How does the moisture sensor indicate soil moisture to us?

This lab went so well! Kids learned how to hook up the sensors to multimeters following the Vegetronix Techno-Gardner video (scroll a bit), how to add water in a measured fashion, and how to account for our soil samples absorbing water kinda slowly.

More on this lab on my full-length blog.

Day 63: Automated Irrigation

Wednesday, 18 November 2015


Toured the greenhouse today. Above is one of the raised beds my classes will be building an automated irrigation system in. There are three main parts to this project: 1) students building and understanding the system that controls a sprinkler valve, 2) the documentation of the system we build, and 3) the interactions with our client (Garden Managers Emily and Joey).

Our system is based around the Vegetronix Soil Moisture Sensor and relay boards.

More detail on this project is coming to my regular blog soon!wpid-wp-1447964039238.jpg

Above, James is showing the kids our 500-ish gallon cistern inside the greenhouse. That’s the water we have to work with over the winter for three raised beds plus the seedlings in smaller containers.


Above, Joey is showing students how he determines how much water’s left in the cistern using a bamboo stick with depth marks on it.

Day 58: Smashing Pumpkins


Out at Discovery* today, we smashed pumpkins to add to our composting area. The kids also added soil to our greenhouse raised beds in anticipation of our irrigation project.

It’s cool how my worlds collided this month — leading a session of Discovery put me in the garden where we’ll be doing a physics project the next few weeks.

*Discovery is the outdoor ed and leadership program all our freshmen take part in. It’s a two week on-campus class that meets a few hours every day after school plus an expedition on the last weekend.

Day 57: Robotic Sprinklers!

Monday, 9 November 2015

Emily came into classes today to introduce them to a new project: an automated irrigation system for our greenhouse. We’ve set the project up where the class is a company and Emily, in her role as helping run the school gardens, is the client. Here, she’s asking the kids where the school garden and greenhouse are.


Above is one of the garden beds that we’ll be setting up with irrigation automation. We’ll be sensing soil moisture and turning on a soaker hose when it’s too dry. I’m thinking we’ll have a system kinda like this.

Day 55: Enthusiastic Learners

Thursday, 5 November 2015

What do you do when a class is so enthusiastic that it’s deafening? Here’s 5th period and I can barely think over their noise. As I move around the room, I hear physics talk — as they work out their lens’s focal length plus setting up five applications of lenses (movie projector, camera, magnifying glass, photocopier, and lighthouse).

By the end of class, though, they were only about 5 minutes behind the studious and quieter 4th period kids.