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27 Apr

Thinking Outside of the (Cardboard) Box

Ninth grade students at Science Leadership Academy’s Beeber campus began the challenge this week of creating their own solar-powered, video-capturing, soil-moisture monitoring bird houses—and maybe even a few bat boxes. Each unit will be equipped with its own Arduino/Raspberry Pi device that will harness the solar power and use WiFi to transmit soil-moisture data and a live “peep show” (get it, because they’re birds?) courtesy of the infrared camera, allowing students to observe the birds inside. As if all of the technical aspects weren’t enough to consider, the students also have to be aware of what kind of birds they’re building for, and choose their houses’ specifications accordingly.

So this week, in becoming aware of their tenants, the students crafted cardboard to scale models of their birds of choice with the help of Alex Gilliam, director of the organization Public Workshop (which collaborates with youths and their communities to help them shape the design of their cities through workshops and leadership programs). And check out the results!

Here we have a few American Robins, a few House Sparrows, and one American Chickadee. Some students also scaled cardboard models of starlings, bluebirds, and bats.

Gilliam encouraged the students to account for both the size of their birds with their wings at their sides and fully spread. They’re each taped to a cardboard sheet inscribed with pertinent information—things like diet, preferred habitat, and how they prefer to nest.

Next week the students will start modeling cardboard prototypes of their birdhouses/bat boxes for their cardboard creatures in order to get the designs perfect for the final products.

16 Apr

Welcome to the Matrix

In our last post, we detailed how soil moisture sensors and datalogging are not exactly the cure for dead plants (or neglectful students). The next step at SLA Beeber was to give students blindingly bright visual cues as to when their plants required watering. Along with taking soil moisture readings and determining a wet or dry state, students programmed their own designs onto an Arduino-powered LED matrix. Remember Lite-Brite? It’s kind of like that, except it’s coded in Arduino using an x-y coordinate system, geometric shape commands and color codes. Students began by sketching their designs onto a 16×32 grid, then breaking the grid into rectangles, lines, and pixels as lines of code:

Adafruit has an excellent tutorial on how to wire this to the Arduino and program it. We put the display inside a Pelican case to keep it dry and set it up in the school’s hallway, where one can only hope the plants’ occasional pleas for water will catch someone’s eye.

17 Mar

Green Sensor Design (and Terrible Gardening) at SLA Beeber

At Science Leadership Academy’s Beeber campus in Overbrook, 9th grade students are learning to program Arduinos to collect soil moisture and sunlight data. The course began with a trip to the Fairmount Water Works to get some background on Philadelphia’s water history, its present challenges due to stormwater and combined sewer overflows, and the plan for an environmentally sustainable future. On the tech side, we’ve covered Arduino basics, Ohm’s Law, simple circuit design (in the photos above, Fritzing came in handy to help students visualize circuits), and the principles behind soil moisture sensors and photocells.

Each student used a datalogger shield to monitor a plant. Alas, monitoring does not equal maintenance. There’s only one bit of green in this otherwise barren dirt farm:

In the coming weeks, we’ll figure out more attention-grabbing ways to make sure students are looking after the plants. (And perhaps a solution to that mess of wires.) Thanks to Drexel University’s ExCITe Center, whose Seed Project funding brought all the electronics and sensors into the classroom.

23 Feb

We Got This, Elon

In an episode of The Simpsons last month, inventor/entrepreneur Elon Musk lands his rocket in Springfield and builds Lisa a futuristic, solar-powered birdhouse. (Some other things happen in between those two plot points, but we’re summarizing.) Not bad, Mr. Musk. Here’s our version:

Many more details to come as we design, prototype, and test solar-powered birdhouses equipped with environmental sensors and infrared video cameras live-streaming to the web. Another version of the birdhouse above is already in the works. Alas, none of our birdhouses have satellite TV or a swimming pool. We just don’t see where there’s market demand for that.

29 Jan

Concluding the Thrilling Saga: The Talking Plant

As the third and final part of our interactive plant display at the Fairmount Water Works, our last plant is now able to talk. That is, it can express its need for water through audio. This setup uses an Arduino ($25), a Wave Shield ($22), and a Vegetronix VH400 soil moisture sensor ($37). Our two 10th grade Science Leadership Academy students had a lot of fun soldering and building the shield. To our delight (and surprise), it actually worked the first time we tried it.

The audio shield will only play .wav files. There are databases with huge amounts of them out there on the Internet. We faced some issues with our .wav files and their compatibility with the device, but after some practice, we began to get the hang of it.

Currently, in an attempt to annoy the Water Works employees (just kidding), each hour the plant takes a moisture reading. If the moisture level is satisfactory, it plays a clip of the song “Everything Is Awesome” from The Lego Movie, to go with the hardware’s awesome Lego case built by the SLA students:

If the moisture level is not satisfactory, it will play water droplet sounds, indicating it needs to be watered. There’s a lot of room for creativity here, because iTunes and Audacity can convert .mp3 to .wav files. What’s stopping Matt from recording himself, converting it, and uploading it to the Arduino? Nothing—he’s probably already started working on it.

View the code after the jump.

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16 Jan

Even Plants are Tweeting Nowadays

As part of our display at the Fairmount Water Works, one our plants will now be tweeting when it needs to be watered. (First the teenagers, now the plants?)

This setup uses an Arduino Uno ($25), a WiFi shield ($80), and a Vegetronix VH400 soil moisture sensor ($37). This WiFi shield has an integrated antenna, which allows us to connect to the wifi at the Water Works and send tweets over its network.

We didn’t want our plant to be someone who only talks to you when they need something, so we have a series of different tweets:

“Water me please!” when the moisture value falls below 250.
“URGENT! Water me!” when the moisture value falls below 150.
“Thank you for watering me!” when there is a change in moisture level of at least 100 and the new moisture value is above 250.
“You didn’t water me enough!” when there is a change in moisture level of at least 100 and the new moisture value is below 250.
“You overwatered me!” when the moisture level climbs to above 400.

One problem we ran into was that Twitter doesn’t allow repeated tweets, as a way to block spam. Because of this, we had to add more content to our tweets. In addition to the text, each tweet displays the moisture level and the tweet number (we added a tweet counter in our code).

You can see our plant’s tweets here.

View the code after the jump.

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05 Jan

Bigger, Better and Brighter LED Display

Our previous post detailed the simple soil moisture sensor with an LCD display that has been keeping track of our plant’s watering needs at the Fairmount Water Works. We decided the project could use a little more flair—plus, our original LCD display got a little wet. Luckily, our new 16×32 LED Matrix has its own waterproof case. The setup uses an Arduino Uno ($25), a Grove base shield ($10), a Vegetronix VH400 soil moisture sensor ($37), and a 16×32 RBG LED matrix panel ($25). All of the electronics are safely tucked into a waterproof Pelican case.

We decided to display more information with our LED matrix. Now, it will display the words “Water me!” when the soil moisture level falls below a voltage of 1.2, or “Don’t Water” when the moisture level is greater than 1.2 V. It then displays the voltage, followed by “Water Works,” and repeats.

We found that with RGB (red-blue-green) matrices like this one, certain colors require more power. When using solely the power coming through the computer to the Arduino to power the matrix, we were limited to basic red, blue, and green colors. Any other colors would be displayed as one of the tree.

We decided this was a little too boring, and experimented with supplying power from the wall directly to the matrix, in addition to the power coming from the wall to Arduino. This got us very bright, vibrant colors. However, the LEDs were glitchy and flashing. We think the matrix was getting just a little too much power, and it was distracting. In the end, we stuck with the additional wall power, but used lower power colors. This gave us the brightness we wanted, without all the flashing.

View the code after the jump.

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08 Dec

Fairmount Water Works Sensor

Now on display at the Fairmount Water Works—a simple soil moisture sensor with an LCD display to keep track of a plant’s watering needs. This is just a first step in developing some really interesting ways to monitor plants and get feedback on plant health. Working with two 10th grade students at Science Leadership Academy, we’ll be investigating how to use visuals, audio, and Twitter to communicate environmental data. (We’ll also be investigating why we didn’t put the electronics in a waterproof case, because what’s more awesome than an unprotected circuit board next to a plant that’s being watered?)

This setup uses an Arduino Uno ($25), a Grove base shield ($10), a Grove LCD display ($14) and a Vegetronix VH400 soil moisture sensor ($37, though you can find soil moisture sensors for under $10; we like the performance of the VH400). The Grove shield stacks on top of the Arduino and lets you use snap-in wires to connect sensors and displays. The Arduino code is after the jump; it’s basically modified code from the Grove website.

We did a rudimentary calibration of the soil moisture sensor and got readings for the sensor in air, in dry soil, in wet soil, and immersed in water. From those measurements, we estimated readings below 200 would probably indicate the plant needs watering. It’s not an exact science, but we’ll learn more about what the sensor output means as we go along.

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24 Nov

Thank You, Philly

As Thanksgiving approaches, we wanted to make sure we recognized how much greenSTEM has benefited from Philadelphia’s collaborative spirit. Last week, MilkCrate‘s Morgan Berman gave a very nice shout-out to greenSTEM in her blog post about how the city’s tech and hacker scene has supported her sustainability app. Berman is absolutely correct about the explosion of multi-disciplinary collaboration in Philly and the positive results.

Berman also mentions Hive76’s Brendan Schrader, who passed away in August. Hive76 is a makerspace I visited one snowy night in 2013 when were just starting to solder circuit boards for our sensor kits. Brendan was kind enough to set me up with some soldering equipment and give me some tips.

Most weeks, greenSTEM is represented at weekly Code for Philly meetups, and we’re thankful for all the people who organize and attend the event and the input and advice we’ve received. Thanks to Chris Nies, Kevin Clough, Lloyd Emelle, and everyone at Jarvus.

Thanks to all the schools, students and teachers we worked with this spring. Special thanks to SLA Beeber’s Dave Sokoloff, who left for Connecticut this year but connected us to a great school that we continue to work with. And none of this real-time sensor stuff would be possible without George Li from the School District of Philadelphia connecting us to the web.

We’re thrilled to have received seed funding from Drexel’s ExCITe Center. Updates on that collaboration will be coming soon.

PWD and the Fairmount Water Works have supported this project from the beginning, and we’re excited to move it forward in the spring and expand the number of schools and students involved.

I hope this didn’t sound like an acceptance speech, because we’ve got so much more to do. If you didn’t already solve the riddle of the previous post, solar-powered, web-connected, sensor-enabled birdhouses are in the works. We’ll be documenting their development on this blog, just as we did with the Root Kit. Spoiler alert: I am a terrible carpenter.

13 Nov

The Shape of Things to Come

Is that a birdhouse? Yes. Yes, it is.