Category: Designing Living Systems


As I mentioned in the previous post, I decided to sprinkle some moistened moss in the tank for a couple reasons. First of all, Aragorn and Arwen were now both in the sand part of the tank, away from the humidity tubes, and we know that moss can retain water and increase humidity levels. Since we had reliable sensor readings for awhile now, I wanted to see if the addition of moss would change the numbers. It also seemed a bit stale in the tank, and I thought moss would brighten up the air quality.

As soon as I put moss in the tank, I felt an immediate rush of cool, fresh air which I inhaled deeply. Aragorn responded almost immediately. You can see his initial response towards the end of the video attached to the previous post, but below is the short video I took with my old little Canon digital photo camera. He was initially shy when I leaned over the tank with the camera but then he overcame his shyness and started moving toward the moss. He even got on top of the moss and then the wood to head towards the moss I put at the top (my little camera can only record a short bit of video, so I wasn’t able to get the wood climb). Given how little movement we’ve witnessed and how shy they’ve generally been, this change in activity and behavior was amazing!

CrabSense: Aragorn loves moss! from Nisma Z on Vimeo.

I later checked the VOC and Carbon numbers and they showed a big drop: 100 to 150! This is proof in the power of moss to increase air quality.

Melissa came in around noon to check on the crabs and tank conditions. The Mac Mini was really hot and when I touched the mouse, the computer crashed, which is unfortunate because we lost all the video recorded overnight (I need to change the code for the Processing sketch so that it auto saves video every hour or so). Apparently Aragorn finally came out of the hut and migrated over to the other side of the tank in the sand area to presumably be near Arwen. We couldn’t find Arwen initially but upon lifting the wood piece, we saw that she was burrowing deep into the sand under it (see video).

CrabSense: Arwen burrowing in the sand from Nisma Z on Vimeo.

Aragorn had positioned himself between the wood and the climbing background. Melissa turned up the humidity to increase the levels, since both crabs were on the low-humidity side of the tank, and misted and covered the lid to keep the humidity in. Around 8p I came in and decided to introduce a bit of moss, which is supposed to retain moisture and increase humidity. Aragorn loved the moss…see the next post about that.

Early in the morning while it was still dark out, Arwen apparently came out of the hut, drank some water, ate part of a pellet, and climbed over the wood and later burrowed in the sand under the wood.  About three hours later, Aragorn came out of the hut, drank some water, possibly ate some of the pellet food, and then went back into the hut. Check out the sped-up video to see the movements caught on camera (yes, I know, we need to set up an infrared camera).

CrabSense: Arwen’s migration to the sand from Nisma Z on Vimeo.

Aragorn came to the doorway of the coconut hut around 1p to say hi to Melissa when she was checking on the crabs – she was delighted by that and sent me a photo :)

The temperature and humidity levels have been good.  I popped in around 10p and misted, turned on the heat lamp, downloaded sound and video files and soaked the towel in water that covers the screen top.

Trying to maintain the minimum acceptable humidity level for the hermit crabs has been almost impossible. We would have to mist the tank every 10 minutes to keep it up, which is obviously not feasible. Yesterday I found this DIY “humidifier” and decided to try it out. I bought an air pump from Petco and a safe water bottle from Kmart.  I set it up and placed the tube inside the tank mid-day.  It definitely did more than just the sponge and water pillows, but still not enough.  There was no visible movement from the crabs on the USB camera.  I looked inside the hut and thankfully the two that were inside there were moving and digging slightly, but the one in the corner wasn’t moving.  I thought it was just resting.  Melissa checked on the crabs in the evening, misted the tank and moved the tube.  She also recoded the VOC and Carbon sensors, added an ozone sensor, and made the whole breadboard more secure. Awesome.

Today I met up with Melissa around noon and we discovered that the one in the corner had died.  We were really bummed out.  Was it because it was too cold, too dry, or just lonely and depressed without a mate?  We know that hermit crabs are social and need to be in groups but perhaps each one also needs to have a buddy or mate?  Looking back at the videos, this crab seemed confused about direction and moved much slower than the other two, so maybe it was sick?  The other two had gone over to it on the first day when it settled in the corner, almost as if to check up on it, but had then gone into the hut and stayed there.  Maybe they knew it was dead and huddled together to stay warm and comfort each other?  Who knows…we’d have to research further and talk to experts.   This death made us determined to fix the humidity and tank conditions and check on them frequently to make sure they’re alive.  I also thought of names finally, inspired by characters from Lord of the Rings.  The one who died is name Boromir, the more adventurous one with the spiral patterned shell is Aragorn, and the one with the light-colored cone shell is Arwen.  I’ll refer to them by name from here on out.

I came back in the evening and saw that the humidity levels were still not quite suitable.  I decided that the DIY humidifier wasn’t good enough, so I did some Googling and found a teardrop-shaped humidifier made by Crane that was referenced in a Vivarium Forum post related to hermit crabs.  So I ran over to Kmart to get this.  Melissa had brought more tubes, so I gaffer-taped four tubes going from the top of the humidifier cone into the tank with outputs at four different parts of the tank.  I immediately saw water mists coming out of the tube ends and watched the humidity levels rise.  Finally!

Just to rant for a second, I’m really quite annoyed that Petco doesn’t sell a humidifier like this for hermit crabs and other creatures that require high humidity, given how essential it is for their well-being.  It is simply irresponsible!  I can’t even believe that local plant stores didn’t carry automatic misters or humidifiers for their tropical plants.  It seems that these stores care only about profits and not about the well being of the living creatures and plants they sell.  Grrr.

Here’s the video that shows some extremely sped-up motion of Aragorn moving around inside the hut:

CrabSense: Aragorn and Arwen inside the hut from Nisma Z on Vimeo.

I spent quite a bit of time today checking on the hermit crabs. Last night the temperature in Manhattan dipped down below 40 degrees, so the tank was quite cold and dry when I came in. I misted quite a bit, which caused the humidity level to rise to 70, which is still a bit too low. I had left the heating lamp on all night but the temperature was also around 70 and should have been higher. I realized I needed to do more to increase both the temperature and humidity, so I went to the pet store to look for some kind of humidifier or automatic mister. I had asked about this initially and was told such an item wasn’t needed if I misted the tank once a day. On today’s trip, I was told that the automatic mister/fogger that they used to sell did not work properly, so the salesperson did not recommend this. He suggested instead that I get a natural sponge, which would provide another way of getting them drinking water while also raising the humidity level. I decided I also wanted to get the water pillows, which would also increase humidity. I was still concerned about the heat, so I decided to get a small heating pad to attach to the side of the tank.

When I got back to the floor, I introduced these items into the environment, all the while capturing double-speed video via the USB camera that I set up previously. It definitely made an impact because two of the three crabs at least responded and seemed to be gathering more moisture from the sponge and moistened dirt. The other crab was alive, just not moving much.

I misted throughout the day and checked all the sensors and audio-visual data, and sent files to Melissa for data visualization. Below is a video featuring the visible movements of the crabs from today.

CrabSense: Nov 1 highlights from Nisma Z on Vimeo.

Today marked the exciting transition between the preparation phase and the hermit crab data gathering phase of our CrabSense project.

When I got to our station on the floor, I checked the sensors that Melissa set up and attached them to the inside of the tank on the upper left side.  I checked the SD card in the DataLogger of the Arduino, and confirmed that we were getting CSV files containing reliable data from the sensors, along with date and time information.
CrabSense sensor and tank set-up
A big part of our data gathering is video and audio, which we decided not to do through the Arduino.  I checked out an AXIS 207W network camera and configured it to send me an email with an MPEG-4 video file whenever the camera detects any motion.  The sensitivity is set pretty high, to hopefully detect subtle movements.  The camera doesn’t really have a wide angle so it doesn’t capture as much of the tank as I’d hoped.  I attached it to a mic stand and set it up on the left edge of the tank, so that the Arduino could also rest on it.

Melissa wired up two small condenser microphones and attached them to quarter-inch plugs.  We checked out the Zoom audio recorder and after inserting a 16GB SD card, I configured it to record MP3 files at a variable bit rate (VBR) so that it doesn’t eat up space.  I  positioned the two mics on either side of the tank and connected them to the recorder on inputs 1 and 2.  I tested the recording and it is indeed producing a good sound file.  We’ll be importing it into a program like Audacity to look for peaks and changes in relation to time.

After getting the tech part out of the way, I then prepared the dirt substrate by soaking one of the dirt “bricks” that we got from PetCo in water, according to the instructions.  I went to PetCo and bought the remaining supplies, including sand substrate, and 3 hermit crabs with changes of shells (I chose crabs with natural shells, versus the painted shells — painted shells aren’t good for them because the paint can crack off and be ingested).  I felt and heard them moving around in their little box as I walked as quickly and steadily as I could back to ITP.  I kept telling them to “hang in there” — silly, I know, but I felt bad for them knowing it must have been so jarring to be exposed to so much movement and noise.

Once back at the station, I poured the bag of sand substrate into the left half of the tank and the moist dirt into the right side of the tank.  I took them out of the box — they were each hiding in their shells — and put them on the sand side, thinking they would like that better.  But within a few seconds of feeling the sand, they decided to move to the dirt side.  I captured their migration in a couple photos and video clips (see embedded video below).

CrabSense Project: hermit crab setup from Nisma Z on Vimeo.

After they huddled, they split up.  The one with the smooth round shell went to the right, front corner of the tank and stayed there.  The one with the cone shell positioned itself by the edge of the coconut house and the tank.  The adventurer with the spiral patterned shell wanted to be on top of the coconut house.  It peered behind the coconut fiber climbing wall and I was worried that it might go behind it, but it didn’t.  It tried to climb up the side of the tank but realized it couldn’t do that.  It eventually climbed down and onto the cone shell crab, who didn’t seem to mind.  Right before I left, I peered back in and didn’t see the adventurer – it must have burrowed into the dirt.

I was surprised that they seemed to prefer the edge by the window, which is colder.  I thought they would prefer heat and sand but apparently it’s the opposite.  I was worried about the heat though. When I was at PetCo, I purchased a 75 Watt bulb for nighttime viewing that also generates some heat and I set that up on top of the mic/tripod stand, so they should be okay for tonight.

I should have taken a photo of the whole tank set up with everything…I was in a rush to catch my train home…I’ll plan to take a photo first thing in the morning.  Aside from the sensors, two mics, and humidity and temperature monitors, the tank is now set up with the sand and dirt, a backdrop for climbing, a large natural climbing structure, a coconut house, four medium growth shells, one clam shell with eight pellets of food, one clam shell with regular water, and one bathing rock with salt water.  We intended to add plants, but we’ll either have to get a bigger tank or swap out the climbing structure with a smaller one to make room.

My project partner, Melissa Clarke, and I are planning to create a vivarium (an enclosed or semi-enclosed container for plants and animals) as well as a sensor kit for monitoring changes in an interior environment before, during and after the vivarium is introduced into the space.  The sensors will also be used to monitor the biosphere of the vivarium.  We want to use sensors that monitor air quality, dust, temperature, and humidity. Check out Melissa’s blog for details on sensors and design drawings.

I was inspired to switch from a terrarium to a vivarium after observing leaf-cutting ants on display at the New York Hall of Science.  I was out there recently for the Maker Faire event and this display caught my attention because I observed adults who were totally entranced by the little ants carrying leaf bits that were at least four-times their size.  Watching the little creatures working so hard yet seemingly nonchalantly was fascinating.  I know, I’m anthropomorphizing the ants, I can’t help it.  I know others will do that as well, so introducing little creatures into a terrarium should dramatically increase complexity and interest and encourage other people to create their own vivariums.

I’m in the process of researching what creatures we should work with.  Crickets are an obvious choice, which reminds me of fellow ITP student Jill Haefele’s Living Headphones project.  I’m more intrigued though by hermit crabs and stick insects, both of which moult.

Hermit crabs are ironically social, so we’ll have to get a bunch.  They’ll also require water bowls and a temperature and humidity-controlled environment.  They love to climb, which makes me want to design little jungle gyms or other such structures to see if they’ll play with them.  Stick insects are among the best camouflaged of all creatures, so spotting them can be challenging but delightfully surprising.  They are mainly nocturnal, so we’d like to add a camera sensor to take snapshots at regular intervals when we’re not around.

The design idea that came into my head when I switched my thinking to a vivarium was a clear double-cylinder (like a large donut), with the inner diameter large enough for a person to insert their head and rotate 360 degrees at their leisure, to observe the creatures and plants in an immersive fashion.  The outer diameter of the cylinder would perhaps be 6 inches bigger, to form an enclosed environment, although the top of it could be a mesh to allow for air circulation.  I like Melissa’s organically-shaped interpretation, although for that creation we’d need a custom glass blower to make it for us.  My cylinder idea isn’t very practical either, so I’m sure we’ll modify our design.

We are planning next to visit some terrarium/vivarium shops around the city to get ideas for shapes, materials and plants.

Today’s class was a field trip to the Phyto Universe spa in midtown Manhattan, where we met with living wall designers Marie Christine Steffanetti and Laurent Corradi.  (Check out my Flickr photos.) Marie worked at the spa for around twenty years and when she became inspired to create a living wall (also termed a vertical garden) within the space, she teamed up with Laurent to form a company and create the first one ever, which was completed in 2005.  It’s wondrous at 13 feet high, containing 9000 tropical plants including types of plants found near waterfalls.  There are plants on both sides of the metallic structure, rooted in pockets created in a special kind of recycled felt from China.  The plants are watered via a pipe running horizontally along the top of the structure with evenly-spaced holes.  Gravity and pipes bring the water down behind the felt and it collects at the bottom and cycles back to the irrigation room. Twice a day, the wall is drip-irrigated in this fashion by zones (there are 14 zones) for 3 minutes each, which uses 30 gallons of water.  There are two kinds of special lights, 150 watts and 100 watts, that face the wall at an angle and need to be on for at least 12 hours per day.  The wall needs weekly or bi-weekly maintenance but they said it’s not a big deal.  It’s a big deal to create a wall like this – the process takes around 2 years – but the benefits are well worth it.

As soon as I entered the space, I noticed the difference in air quality, and when I was within 3 feet of the wall, the freshness and purity of the air was amazing.  I utilized my yoga breathing and just inhaled deeply while they showcased various plants and other details.  I didn’t want to leave.  I hope someday to have a vertical garden within my own living space and work environment.  In the meantime, I’m inspired to work with my class on figuring out how to collect and visualize data on the benefits of these kinds of walls.

Last week’s assignment was to photograph “living systems”, and today we looked through the photos that everyone took.  I snapped a sample of images that represented different systems that I encounter in my daily life – bees, butterflies, spiders and other insects interacting with flowers and plants along the path I take to Brookdale Park in Montclair; the relationship of moss and trees; the self-organizing group of dogs and their owners in the ecosystem of dog parks; the self-organizing group of frisbee players in a park (Washington Square Park, near ITP); and the transfer of energy, matter and humans within a train system.  I uploaded my photos to Flickr.

Some of the photos I liked from others included native plants at the High Line Park; ivy on buildings and mold on sidewalks as examples of nature reclaiming the built environment; a ladybug condo experiment (fun idea although it sadly didn’t work); mechanical systems like air and water filters to contrast with how nature handles these tasks; and artistic interventions like moss graffiti.

Dickson Despommier spoke to us about the concept of vertical farming and presented an excellent PowerPoint presentation, full of innovative conceptual designs along with depressing statistics on climate change, deforestation rate, population growth (by 2050 we may reach 10 billion people), harmful agricultural runoff, and lack of available farmland.  He stressed to us that repairing the environment should be the number one focus.  Given that around 80% of humans will live in cities or suburbs within the next 20 years, it makes sense to focus on solutions like hydroponics and vertical farms for making food production viable and efficient in an urban environment.

New York City apparently discards around 1 billion gallons of water per day.  Vertical farming remediates gray water, whereas traditional agriculture uses 70% of available fresh water.   He explained that in a hydroponic system, “ultra pure reagents” are inserted into the system to provide plants with the elements they need to filter carbon.  He doesn’t see a problem with purchasing these chemicals from companies like Monsanto, but I disagree with this – the nutrients needed by the plants should be generated organically.  Aquaponic systems can provide a self-sustainable, self-feeding system, although I understand they are complicated to get right.

Some of the designs for vertical farms and gardens that he highlighted were Andrew Kranis’ spiral design, the Pyramid Farm in Dubai by the Grimshaw firm, the Pla(n)tform from Israel, Oliver Foster’s “VF – Type O” from Australia, and bringing it back home, Jung Min Nam’s Urban Epicenter for NYC.

One of the cities interested in actually proceeding with the first vertical farm is in New Jersey…I hope the project gets green-lit soon!