11 Apr

Rain Barrel to Inbox: I’m Full

The next generation of scientists and engineers at Philadelphia’s Penn Alexander School are developing the next generation of rain barrels. The rain barrel, of course, is a staple of the Philadelphia Water Department’s Rain Check program, aimed at enabling residents to manage stormwater and prevent pollution from entering our rivers and streams.

PAS Tesla Robotics, a group of middle-school students who convened last year to compete in the FIRST Lego League competition, decided to take on an issue that affects the approximately 3,500 Philadelphians who own rain barrels: How do you ensure that residents empty their rain barrels before a storm? And how can we know that the barrels are effectively capturing water? The students invented Tessa, a smart, sensor-enabled rain barrel that can send a text or email to let people know when the rain barrel is full. In order to accomplish this high-tech feat, the group researched sensor technology and microcontrollers, learned to code in C++, and set up a cloud data service to send rain barrel notifications straight to a cell phone.

This week, PAS Tesla Robotics demonstrated Tessa to PWD, the Pennsylvania Horticultural Society, Drexel University and engineering firm AECOM; they expertly explained Philadelphia’s combined sewer overflow problem and the need for effective rain barrel management. The students are honing their presentation for the FIRST world championship in Detroit later this month. (Did we mention the team already won local and state competitions?) The live demo included a successful email notification from the test barrel when the barrel sensed it was full. And, of course, the team has already identified several improvements to the device, such as a more accurate sensor and incorporation of weather forecast data—stay tuned. Best of luck to Tessa and PAS Tesla Robotics in Detroit!

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!

Photo credit: Matthew Fritch

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.

16 Apr

Student Design Competition


Last week, judges met at the Fairmount Water Works to view the submissions for the greenSTEM Challenge, a student design competition to create artistic, original housings for the sensors set to be installed at three Philadelphia schools later this month. Competition was fierce—the student team at Greenfield who submitted the zombie head design deserves an honorable mention—but we selected three winning designs: a sword in the stone (Greenfield), a spider (Nebinger), and a futuristic light-up dome (Cook-Wissahickon). The winners are below; the next step is to gather the students for a day of building.

Greenfield Elementary: Zoe, Alexei, Jordan


Written Description:

Over the device we will put a block of foam that hardens for more durability. We will make a sword handle out of water bottles filled with paper and pipes. We will spray orange, brown, and silver paint on the pipes. We will also spray paint the foam silver. The end result will be an homage to the classic story of King Arthur. The wires will come out of the foam. The device will be obscured in a nice cover that complements the color of its surroundings and the storytelling we grew up with. The foam will be covered in dirt and rocks to blend in with the ground.

Nebinger Elementary: Amir


Written Description:

My project is a tarantula. I will have the device inside a Pelican 1010 casing with straws. I will put the wires inside the straws and have the other end connected to the head of the tarantula. I made it easy for you to figure it out in these pictures.

NEBINGER_design2 NEBINGER_design3

Cook-Wissahickon Elementary: Jonathan, Jhalil, Sean


Written Description:

We will have a plastic dome around the data-sending unit with LED lights inside the top of the dome. We will use battery packs to power the LED lights [to indicate] when it needs to be watered. We will use a circuit board to turn on the LED lights because it will be hooked up to the sensors.

Congratulations to the students! And thank you to the judges: Beth Miller (Community Design Collaborative), Alex Gilliam (Public Workshop), Lisa Wool (Partnership for the Delaware Estuary) Ellen Freedman Schultz (Fairmount Water Works), and Tiffany Ledesma-Groll and Jay Cruz (Philadelphia Water Department).

19 Mar

Root Kit Construction


With the installation of sensors at four Philadelphia schools about a month away, it was time to build some additional Root Kits. Version 1.0 is housed in a Pelican 1010, a $10 waterproof case normally used for stashing your cell phone during whitewater rafting trips or something. We used a half-inch drill bit to drill out the three holes for the soil moisture sensor cables, and the cables are secured to the case with PG7 cable glands (about $3 for a pack of 10) that you can tighten by hand.

A few words about drilling: This was a two-person job; one person steadying the left side of the case and the other drilling, slowly and with constant pressure, the three holes. At first, we experimented with drilling pilot holes with smaller bits and moving up to the half-inch bit, but by the end we just did the job with the half-inch bit from start to finish. (We haven’t yet cracked the plastic on the Pelican cases, but have definitely destroyed a variety of less-sturdy plastic components while drilling.) It was difficult to align the holes and make it look pretty. The drill bit walks. This is not of great concern, however, since these cases will eventually be covered by students’ creative and artistic designs.

Speaking of which, students at Greenfield, Nebinger, and Cook-Wissahickon elementary schools are currently designing Root Kit housings for the design competition. The deadline for submissions is April 4, and more info and downloadable packets and drawing templates are here.

We’re in the process of assembling a complete set of instructions for assembling the Root Kit and plan to work with students at Science Leadership Academy’s Beeber campus this spring to be the first large-scale manufacturers of these sensor kits.

19 Jun

Snakes on a Playground

Snake_Sensor_partsThis summer, the playground at Nebinger Elementary School in Bella Vista will lose some impermeable asphalt and gain a rain garden and some porous play surface. It’s all part of a plan to capture stormwater and protect our rivers and streams. But after construction is finished and the vegetation is planted, students may not even realize the function of the system in place.

Thanks to an engaged principal, faculty and educators from the Fairmount Water Works Interpretive Center, however, students are already learning about water-related issues and getting ready for a greener play area (the school already has a very productive vegetable garden in raised planter beds). When teacher Rachel Odoroff was looking for a year-end project for her 7th and 8th grade science classes, we saw an opportunity to introduce some of our work with sensors into the classroom.

The challenge: In two days, work with the students to design and install some sensors to monitor the vegetable garden.

The plan: Well, it’s a bit too ambitious to try to access the school’s WiFi network and get the Solar Sunflower server to display the data, so we decided to make a datalogger to record soil moisture and temperature in the garden. We gave the students a short introduction to the electronics, and they got started with designing the housing. The result? A snake made out of a tupperware container for the head, and pieces of flexible plastic plumbing connectors (the kind you might use to connect pipes under your sink).

Below is the “head” of the snake: an Arduino, an SD card shield (data is written to an SD card, like the memory card in your phone or camera), a battery pack with 4 AAs, and red LED “eyes” that light up when the soil is too dry. The temperature sensor is a black wire that protrudes from the front of the head, like a tongue.


Here is the head of the snake in the garden, placed among some tomato plants:


The tail of the snake—the soil moisture sensor‘s wire threads through the tubing and the sensor is buried about four inches in the ground:


Unfortunately the end of school means the students won’t have an opportunity to examine much of the data, but we’ll be back during the summer to check on the snake every once in a while. We hope to build on this project next year—add wireless communication, upload data to the web in real time, add a light display—and extend it to monitor the rain garden. Thanks to Ms. Odoroff, her students, Drexel co-op Tommy Thompson, and Fairmount Water Works education and outreach coordinator Ellen Schultz for making this project happen. Thanks to PWD engineer Stephen White for coming up with the phrase “snakes on a playground.”

24 May

Greenfield Site Visit


As detailed in a previous post, Greenfield Elementary School in Center City Philadelphia is one of the Water Department’s “green schools.” (It’s an environmentally conscious school in its own right, regardless of PWD’s designation, but the green stormwater infrastructure at the schoolyard is what connects the Solar Sunflower project to it.) Earlier this week, we paid a visit to the school during an in-service day (a day without students, when teachers receive some training) to present the project to the faculty and scope out possible spots for installation.


There’s good news and bad news about Greenfield, at least for the moment: On the challenging side, the main schoolyard and rain gardens are pretty much open to the public—the space is not gated or closed at night, so that leaves the Sunflower or any type of sensor setup vulnerable to vandalism. It isn’t a dealbreaker; we just need to invest much more time into securing sensors and electronics inside heavy-duty housing bolted into concrete or enclosed in a junction box.

Then we were taken around the side of the school and saw … the secret garden. It doesn’t contain green stormwater infrastructure, but it’s secured behind a padlocked gate and serves as an outdoor classroom for the kindergarten classes. Additionally, the library window overlooks the secret garden:


This makes it possible to do something visual with the sensors in the garden—maybe an LED display lights up when the soil is dry, and students looking out the window can get the bat signal to go out and do some watering.

15 Feb

Green Schools: Greenfield and Nebinger Elementary


Now that we have the idea of a solar-powered, sensor-equipped sunflower that allows students to monitor plants in a rain garden, it’s time to think about where that sunflower will take root. Greenfield Elementary School in Center City has been a model of a “green school”: In 2009, the Philadelphia Water Department worked with the school’s parent group, the Philadelphia School District, the Community Design Collaborative and the EPA to transform an asphalt schoolyard/parking lot into an attractive, green playground (pictured above) that manages stormwater using rain gardens and porous play surfaces. Watch the video below for more detail:

A similar transformation is about to take place at Nebinger Elementary School in South Philadelphia (actually, Bella Vista—you can start a small war in Philly if you’re not careful about getting the neighborhood correct). This summer, construction begins at Nebinger to create a rain garden and porous play surface where asphalt used to be. The rendering below shows what the greened schoolyard might look like. The rendering below also shows what it might look like if a child with one foot were running—you see that guy in the background?


Schools are great locations for green infrastructure. Blacktop schoolyards tend to be large impervious spaces that normally contribute a large volume of stormwater to the sewer system. Schoolyard makeovers can revitalize play areas and introduce nature to the urban landscape. Having the students use technology to monitor their vegetation adds another layer of connectivity and offers even more opportunity for STEM education.