22 Mar

Root Kit 2016


As seen on Twitter: Philadelphia Mayor Jim Kenney speaking before an image of our very own Root Kit. Mayor Kenney was on hand to kick off last weekend’s Democracy Hackathon, and greenSTEM is very proud to have worked with civic hackers at Code for Philly to develop the hardware and software that went behind the Root Kit, a web-connected soil moisture sensor for rain gardens and other green infrastructure. If you’re looking to get involved with technology projects that benefit your neighbors and the city, stop by one of Code for Philly’s weekly meetups—no coding experience required.

But the point of this post is not merely to tout our product placement. A next generation of the Root Kit is coming. It’s even more advanced than the Soil Cell. It’s more powerful, less expensive, and open source all the way. As always, we’ll document how to build one of your own once we figure out all the problems with it have some nice photos.

07 May

SLA Beeber Wins Drinking Water Award

Photo Courtesy: Virginia Vassalotti
Photo Courtesy: Melissa Bittner

On Monday, the Schuylkill Action Network gave SLA Beeber students the 2015 Scholastic Drinking Water Award. The 9th and 10th graders have worked with the Philadelphia Water Department’s greenSTEM project  in weekly courses. SLA Beeber was one of three award winning schools across the Schuylkill River Valley. Schools that have won the award in the past have demonstrated exemplary stormwater management practices, or conducted class projects or educational programs pertaining to clean water. SLA Beeber won this year’s award for participating in our Root Kit project,  where they programmed Arduinos and sensors to monitor and record soil moisture data.

The high school hosted an assembly to honor these students for their hard work, which was attended by representatives from the Schuylkill Action Network, the Environmental Protection Agency, and the Partnership for the Delaware Estuary. Several of the students spoke about their work with the Root Kits and explained what they had learned about the importance of protecting drinking water through green stormwater infrastructure and visits to the Fairmount Water Works during their mini-courses with PWD.

Photo Courtesy: Virginia Vassalotti
Photo Courtesy: Melissa Bittner

The students also demonstrated how their project worked to monitor soil moisture and keep plants healthy. The photo above shows one student showing off a Root Kit they kept at the school, which not only takes soil moisture readings but displays  whether the soil is in a wet or dry state through an Arduino-powered LED matrix the students programmed themselves. The student explained that when the plant needs water, the screen will flash ‘DRY’ and when the soil is adequately moist the screen will read ‘WET.’

Jon Capacasa, director of the the  Environmental Protection Agency’s Water Protection Division, spoke about the importance of collaboration with students and educational facilities to help protect drinking water and presented the group with a plaque commemorating their achievement.

12 Jun

Fourth Installation: SLA Beeber


Students at Science Leadership Academy’s Beeber campus installed Root Kit #4 yesterday, capping off an 8-week minicourse of designing and building the sensor housing, soldering the kit’s circuit board, testing radio signal strength, and troubleshooting along the way. Remember the waterlogged sensors from a few posts ago? We did an immersion test and found out water was leaking into the Pelican case at the base of the cable glands:


We used a combination of Rust-oleum Leak Seal spray (not that effective, smells toxic) and silicone caulk (it works, but it’s messy-looking) to waterproof the case. After connecting to the school’s network and testing signal strength from the flowerbed to the 3rd floor office, students buried the soil sensors:


The students went with the eyeball housing for their site, and designated the rocketship design for a future installation at the Franklin Institute this summer (details to come). We poked a pinhole into the eye’s center to allow the antenna to peek out:


Thank you to all the SLA students, Mr. Sokoloff, Darya Drahun and Sandy Sorlien—mission accomplished!

05 Jun

Third Installation: Greenfield Elementary


The sword in the stone now sits among other stones at Greenfield Elementary School. This stone, however, hides a Root Kit, sending soil moisture data to our growing tree. A slight modification was made to the stone when we drilled a pinhole in the top for the Root Kit’s antenna to poke out. Increasingly, we’re finding out that a line of sight between the two antennas is an important factor in keeping the radio signal alive. (For a refresher on how this set-up works, go here.)

Thanks to Mr. Bentz and his 8th grade class, who buried the sensors; and to Drexel co-op Darya Drahun for technical assistance. We noticed during our visit that Greenfield is installing a green roof directly below the science classroom; this would be a fascinating new home for the sensors next year.


03 Jun



Mysteriously, the sensors at Nebinger and Cook-Wissahickon elementary schools stopped transmitting data late last week. A trip out to each school’s garden quickly revealed the problem: waterlogged Root Kits, with circuit boards and battery cases floating in water. Weren’t these things supposed to be waterproofed? Not against last week’s heavy rain, apparently. We have a hunch as to where the water is getting in; students at SLA Beeber will conduct an immersion test (i.e., put the case in a bucket of water) to see where the water is leaking in and recommend fixes. But for now, the Root Kits are sidelined and drying out, and we’ll test the circuit boards to see if they still work. Check out the futility of the dessicant pack in the photo below:waterlogged_RootKit2

02 May

Eyeballs and Circuits


Week 2 at Science Leadership Academy’s Beeber campus saw the students begin constructing two aspects of the Root Kit: the circuit board (a JeeNode, which is a low-cost, low-power microcontroller with a radio transceiver) that controls the sensors, and the artistic housing that will cover the Root Kit outside in the garden. One group of students soldered while the other group painted.


We followed JeeLabs’ excellent step-by-step instructions to solder the microcontroller boards. The students are charged with creating their own do-it-yourself manual for creating Root Kits, and their main tips for soldering were 1) Keep track of how long the solder wire is—too long and you don’t have much control, too short and you increase the risk of burning yourself; and 2) Soldering gets easier as you go along. Definitely good advice.


The students also got to work on their two housing designs: an eyeball (above), and a crashed rocketship. The eyeball came together quickly: acrylic paint, some glitter glue, and a plastic bowl. It looks excellent—I hadn’t considered how these designs need to be bold and simple; they should be apparent amid garden vegetation from a third-floor classroom window 100 feet away. The eyeball achieves that. More on the rocketship design next week, as we didn’t have quite the right cutting tools for the plastic fins. Student tip for working with recycled 2-liter soda bottles: Use a base coat of white paint first, then put a color coat (in our case, silver) over top of it. The first coat doesn’t adhere well to the bottle’s plastic.

A word of advice for procuring housing materials: Dollar stores are your friend when you can’t find recycled plastics that fit your design needs. Ideally, we’d use recycled materials 100% of the time, but sometimes exceptions are made. Just make those exceptions as cheaply as possible.

24 Apr

Design Day at SLA


Yeah, that does say “duck butt” on the whiteboard. It’s a long story. At Science Leadership Academy’s Beeber campus, a 9th grade class is becoming a company. Its product is the Root Kit, and over the next 8 weeks the students will be responsible for building the kits, soldering the circuit boards, designing the housing, building the housing, installing the sensors, troubleshooting the kit, and creating a do-it-yourself construction manual for other schools. Is that too much to ask?

Yesterday, the SLA Beeber students did some rapid idea generation (I can’t stand the word “brainstorming”) to come up with concepts for the Root Kit housing. Factors to consider: This will be out in a garden, so it has to stand up to the elements; it doesn’t have to be waterproof, but it can’t be made of cardboard and paper, either. Using recycled materials whenever possible is good. And it can’t be made of metal—the radio signal from the Root Kit doesn’t carry well when the antenna is enclosed in metal.


Look back at the top picture and you can see that, based on the distribution of Post-It notes on the whiteboard (a Post-It indicates a student liked an idea), there was little consensus. None at all, in fact. Not even a hint of it. At the end of the day, we narrowed it down to two designs (an eye and a crashed rocketship) based on … I’m not sure, exactly. Buildability was one factor; the garden gnome was a great idea, for example, but we lack the sculpting skills to make it happen at the moment. Also, SLA Beeber’s mascot is a rocket, so that design seemed apt. It’s buildable, too, perhaps using two recycled 2-liter soda bottles.

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.

15 Nov

Re-branding: “Root Kit?! Not on my network, pal!”

root kit complete

This is our physical product. We are calling it a Root Kit. The Root Kit is a do-it-yourself environmental sensor kit for schools to be able to wirelessly monitor rain gardens and other vegetation in real time on the web. On the left is the data receiving unit; it sits inside the school and receives sensor data from the object on the right, the sending unit. It is contained in waterproof case and is equipped with a temperature sensor and three soil moisture sensors. The soil sensors get buried in the ground and almost act as roots. This is the Root Kit.

Now, tech-savvy people will howl at the name, because a “rootkit” is a dirty word among IT and network security professionals. You see, a rootkit is techspeak for malicious software that invades and attacks servers and computers. Tell a school district IT person that you’d like to install a Root Kit at the local elementary school, and you’d better be prepared to run.

We still like the name. Much like the term “hacker,” we want to turn the meaning of “rootkit” on its head and have a little fun with the terminology. So who wants a Root Kit?