Raspberry Pi Powered Soil Moisture Sensor Irrigation Control System

Life is more interesting when you get to choose your own projects! My first independent, large-scale project is a soil moisture sensor irrigation control system.

Conceived, designed and built during my time @ UCLA for an urban farm in Inglewood, CA. Here's a quick video showing my first prototype:

This system (+testing, analyzing, fixing, writing a massive paper, and presenting) allowed me to get an MS from UCLA's MAE department! Woo! So it worked, but wasn't ideal. Slowly but surely, I am still working on it. It's getting there! Currently all aspects of the system are solar powered (via rechargeable batteries) and wireless. Much more work to be done, but it's getting to a workable version.

The first viable prototype will be installed at a school garden in Inglewood, CA. It will automate the irrigation system for the garden, reducing overall water usage, improving crop yields, and exposing students and community members to engineering, programming and problem solving as it pertains to their own lives.

More Maker Corp Shenanigans!

Presented with a challenge of designing something using "alternative e-textiles",  I immediately wanted to make a flower crown. Why? Because who doesn't love flower crowns?! Plus, a friend made me one around Easter time and I more than loved it. Adding lights/electricity to my own creation just sounded too awesome to pass up.

My first flower crown was made using materials from the recycle bin at The Exploratory: silver auto lining (or something like that), fake flowers/leaves, and old wire for wrapping. Once the crown was made, I added two LEDs in the front and a series of four in the back.

This first crown was cute and will never wilt, but I just HAD to make one with real flowers! So, I wandered around my neighborhood and picked some bugambilia (had to look up how to spell that one..). These are super beautiful vine bushes that grow everywhere in LA; the only catch is that you have to be very careful when picking/working w/ them b/c the spines will definitely draw blood. It is highly recommended to locate & snip off these thorns prior to any work w/ the bugambilia.

 Flowers in hand, I followed the vague directions my friend rattled off to me when she presented me w/ the fabulous, living flower crown:
1. Wrap the flower stem/vine w/ wire to make it flexible.
2. Bend stem to desired shape.
3. Wrap second flower stem/vine w/ wire and attach to first.  Bend to desired shape & repeat.
4. Have patience and be willing to work on this for at least an hour. You will probably get frustrated, but keep going!


Now for the e-textiles part of the living flower crown!
A ribbon seemed like an easy and aesthetically pleasing way to add multiple LEDs connected in series to one another. I also wanted a way to turn the LEDs on/off when the crown wasn't being worn, as well as a way to reuse the LED ribbon strip w/ a new crown (since real flowers do wilt..).


The series of photos below shows the design and construction process of the LED ribbon and battery case. The coin cell battery holder acts as a way to replace batteries and to provide the conductive pads for both sides of the battery (just like a traditional battery case!).

It was somewhat successful, but I ran into an interesting, unanticipated problem: out of five LEDs (one white, two blue, one yellow and one orange), only the yellow and orange LEDs on the ends would light up! The blue and white LEDs weren't even flickering.

Eventually I realized why this was happening, but I will leave it up to the reader to figure it out on your own ;) (it's a super cool physics problem).

And now for something completely different: ArtBots!

 

My first artbot came to life this week! Well, maybe not 100% fully as-anticipated alive, but sort-of Frankenstein-esque alive. 

 

 

I started with the intention of building an artbot able to handle different materials, be it pencils, markers or paint. My first reaction to this provocation was to build quick and simple arms w/ hands using alligator clips hot glued to wooden BBQ skewers.

Next was the body; choosing a cylindrical body of lightweight plastic (recycled takeaway container) allows for freedom in movement and reduces the amount of power needed to drive the artbot (b/c of less weight). The first idea to pop into my head after selecting the body was to use a motor to spin the artbot in circles. So, I set about making four wheel + axle combinations with plastic wheels, BBQ skewers and lots and lots of hot glue.

Once the four wheels + axles dried, I eagerly glued the first two wheels onto the artbot on opposite ends of the body. A small voice in the back of my head wondered how wheels with only one axis of rotation could spin an artbot in circles... but the first two wheels dried, and awesome, it moves! But also falls over, so onto stability!

A quick design process ensued to determine the best method of attaching the remaining two wheels that allows for a range of motion (preferably circular) while providing stability. My conclusion was to cut a hole in the body on both sides, push a small skewer through, and glue the wheel axles onto that skewer.

Tons of dried hot glue later I realized this may have not been the best method with only four wheels; the bot couldn't move without falling over. A quick solution to salvage my work was to glue the top skewers to the body. This eliminated the potential for circular motion, but allowed the artbot to stand and move forward or be steered in different directions.

I had conquered the artbot! Except, I forgot to incorporate the motor + transmission into the design. Whoops. At this point, the wheels consumed a good deal of time and were decisively hot glued onto the axles; aka no easy way to attach a motor and gear system with available materials (mostly rubber bands) without creating new wheel/axle combos and re-gluing to a new body. The next best possible solution (aka quickest and easiest) was to use a propeller. Attaching the motor + propeller and a 12 V battery to the top of the body eventually did the trick! A simple switch built out of a paperclip allows the user to turn the artbot on and off (although the other motor/battery terminal connection is less than perfect, so an alligator clip is also used to create a better connection and act as a switch).

I'm pretty sure this artbot should come with a warning b/c of the furious propeller.. but the process was an ideal lesson in how the first design/concept rarely makes it to the final stage. In the end, it was awesome to see how it turned out, + many ideas for creating a better one next time!