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!

Random Musings: Finding Meaning in Science

So, based on my few years of experience into adulthood, it seems like (almost) everyone is frustrated and tired and just wants to be a kid again. Me too! Although most of the time I still feel like I'm five years old.

The mystery and wonder of childhood is a relief to the supposed emptiness and meaninglessness of our actions as adults. We silence the mystery and wonder as we get older. We silence it so that we can work at a job we hate, talk about subjects and gossip we do not truly care about, and remain stagnant in our self-growth in order to cope with this fast-paced, emotionless, technological world we have created for ourselves; this world that is so unfulfilling to almost everyone, this world that turns you into a silent worker and a unsatiable consumer instead of a living, breathing, thinking, exploring being

Life itself is incredible. It enables endless questions! We are made out of the same matter as every visible object, yet we are able to experience and explore ourselves and the world around us. In our own galaxy, there are 9  8 planets that are not even remotely close to sustaining life long enough to get to sentient beings. We are searching the stars for the slightest hint of life in this vast universe. Life, as we typically define it, is rare and precious and amazing and literally unbelievable. It took billions of years just to get to the point where elements could bond to other elements, forming larger, more complex structures.

To me, that is meaning, that is wonder, that is mystery. Everything that we experience is the universe knowing and experiencing itself. We are the universe, the universe is us. Or as Carl Sagan once said, "We are a way for the universe to know itself."

Random Musings: Observer Effect

One of my favorite subjects is the observer effect: when making a measurement on a system, the act of measurement alters the state of the system.

I first learned about the observer effect through the lens of quantum mechanics, where the concepts are mind boggling and the math is a bitch. More specifically, quantum superposition: an electron exists in every possible state until a measurement is made on that electron, causing its wavefunction to collapse into a single state (e.g. measuring the location or spin of an electron in orbit around the nucleus of an atom)

The observer effect is demonstrated by a relatively simple experiment: double-slit interference, or Young's Experiment (..sort of)[1].

A home-made double-slit interference experiment is possible, although it may take some patience. The basic procedure:

• Cut two parallel slits in a piece of cardboard (preferably black), separated by a millimeter or so (doesn't have to be exact). 
• Place the cardboard in front of a screen and shine a high intensity beam (e.g. laser pointer) onto the cardboard (may have to adjust the distance from the slits to the screen).  
• The resulting pattern on the screen is a series of alternating light and dark spots, like this photo from an MIT Physics Technical Services Group experiment:

Or just watch the experiment to see how it is done w/ fancy lab equipment.

And if you really like math, check this out! 

Double-slit interference is due to both the particle- and wave-like properties of light. When light waves pass through a small slit, they diffract, or bend. The direction of the light waves changes as depicted in the photo below.

The bent light wave emerging from each interfere with each other. When the light waves are in series (e.g. a wave crest hits another wave crest), they add together to produce a bright spot, known as constructive interference. When the two light waves are out of phase (e.g. a wave crest hits a wave trough), they cancel each other out and produce a dark spot, known as destructive interference.

Light waves, and all electromagnetic waves, are carried by photons (massless elementary particles). Photons transport the energy of the laser beam to the cardboard, through the slits and to the screen where they generate the interference pattern. The higher intensity (aka brightness) of a light beam, the more photons are being emitted.

Ok, so back to the Observer Effect!
Take a double-slit interference experiment and put in light detectors spanning each slit. Since photons are particles, the detector records when each quanta of light passes through the two slits. This data allows us to calculate how many photons pass through each slit. Logically, we expect that approximately 50% of the photons pass through one slit, while the other 50% pass through the other slit. Seems reasonable.

Well, it doesn't happen. The interference pattern disappears. When there are detectors recording the path of the photons, all of the photons pass through a single slit. Remove the detectors, and the interference pattern reappears.

Note that the observer doesn't necessarily have to be a "conscious being"; a computerized detector works just as well as our eyeballs and subsequent electrochemical reactions. What is so insane to me is that somehow the photons are aware of the detector. My best understanding is that the measurement device, or the "observer," forces the photon to choose a slit to go through, rather than passing through both slits at the same time (literally being in two places at the same time, aka quantum superposition).

The more I learn about the how the universe works, the more I am seriously blown away.

Is this an Intro?

“You never change things by fighting the existing reality. To change something, build a new model that makes the existing model obsolete.” Buckminster Fuller

Ok.. so why this?
Here's what I'm gonna do w/ this virtual space, in a list format, because lists are easy:

• Organize, outline, and track projects I am working on (too many projects! not enough documentation.);
• Document ideas to see which ones I like and want to continue working on;
• Store and share awesome and inspiring creations & ideas by other people (e-mail and facebook are just not working);
• Have a "paper" trail of my progress to feel accomplished by small steps.. and as motivation.

I'm running out of post-its, so here we go.