blog :. joão costa

@ Interactive Telecommunications Program

energy final


After a lot of pondering, I chose to work with an extremely low-power circuit instead of using the real time clock module and keeping track of time. In that way, the amount of current needed while the system is in sleep mode is approximately 11mA, which will maintain the battery on for a long time. The peak of current occurs when the motor takes a step (approximately 100mA) and ten seconds after that – keeping the coils energised to make sure the rod doesn’t move after it has taken the steps. Then, it is time to sleep, the Arduino enters its low-power mode and stays like that for 5 hours 27 minutes and 50 seconds, after that it lights up the LED on pin 13 that stays on for 30 seconds, alerting that it’ll move soon, it then blinks three times and the cycle starts again.

The LED procedure is due to the decision of using a ball pen instead of a pencil. The pencil was requiring too much pressure to make a visible line, and the motor couldn’t handle that. Therefore, I need some kind of signal in case the pen needs to be changed, so the LED is a warning sign to hurry up or wait until it has moved.

A counter weight was added to the aluminum rod in order to calibrate the pressure of the system. It acts just like the arm of a turntable, the pressure on the pen varies according to the distance of the weight in the bar.

Code is here.

Circuit IMG_0699


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energy final : progress

The circuit for the final is almost done. It consists mainly of an Arduino Pro Mini 3.3V, the Real Time Clock from Sparkfun and the EasyDriver stepper controller. Connected to the Voltaic V15 battery, the driver can be powered by 5V and still provide the regulated voltage to feed the microcontroller. For the clock I had to use a 560Ω pull-up resistor from the 5V in order to not burn it (I saw some smoke when I had it connected without the resistor). I believe its internal resistance is set for low current sources such as the 5V from Arduino, so when I connected the 5V 1A from the battery it drew almost full current.

The deal now is to choose between having a code that will keep track of the time (in order to know the position of the stepper) or to make a really low-power system and rely on the battery. The first option can sound more appealing because of obvious reasons but, when thought through, it has some complications that might affect the power consumption and will make the code more difficult. If I choose to go down this path I’d have to keep the Arduino awake and writing information to some kind of memory (EEPROM or SD card) at all times. This is because, assuming the circuit could go out of energy at any time, I’d need to keep the memory updated with the most recent information. On the other hand, if I do the other way, I will have the Arduino in deep sleep, without anything going on, for intervals of 2 hours 44 minutes and 15 seconds, then it’d be on for half a second and go back to sleep again. Doing some rough calculations, I estimate that the battery would last approximately 150 hours without any sunlight, that’s almost a week without recharging, which is rather unlikely.

I still have to make some decisions, but that’s where I am right now.

Ps.: meanwhile I built the enclosure for the circuit. It will live on top of the paper.





energy : solar challenge documentation

The solar challenge reached its end. Please refer to this link for a more in depth understanding of the components of the circuit.

The final circuit is drawing 5.94 mA while in sleep mode, using the JeeLib, and when writing to the card it goes up to 22 mA. I ended up using the 6W Voltaic Systems charger kit instead of my 3.7 LiPo battery and charge controller from Adafruit. I realised, after assembling the whole system with the 3.7 V battery, that the real time clock only works with 5V. Ideally, I would be able to get a booster step-up converter that would fit perfectly on my circuit, but time ran short so I went with the 6V battery.

Code is here. (It’s kinda messy, I apologize)

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Screen Shot 2015-04-07 at 2.58.18 PM

energy : final pitch




a drawing machine that takes one year to achieve completion

For the final project I will build a solar powered system that will use the length of a full year to draw a circle. I wanted to work on a project that was disconnected from the grid and could live almost on its own, the sun being its only dependence. A project like this not only practically, but also in the conceptual scope, must occur in a really slow tempo, it asks for an specific time. And that time is the duration the Earth takes to orbit around the Sun, which occurs in the course of one year. I believe this work, above all, is about the poetic of movement – small steps that can barely be noticed – or even that can’t be perceived, unless you give time for it to happen.

What differentiates a circle made in five minutes, from a circle made in a year? We have been fascinated by the increase of speed technology allow us to obtain, but this time I want to explore precision in a long period of time, and this will have to be made in an accurately way. It is amazing how a ‘slow project’ has a lot of issues attached to it, whereas if this was a fast-paced work it would’ve been much more easier in a lot of ways. I believe dynamics here are quite intriguing – how the energy source that moves the mechanism is kind of accompanying the work, they’re both resonating and it one is almost an extension to the other.

materials »

+ stepper motor 400 steps / rev - $16.95

+ sparkfun easy driver - $14.95

+ arduino pro mini 3.3v – $9.95

+ real time clock – $14.95

+ 6 watt solar charger kit – FREE (thanks Voltaic Systems!)

+ 8b pencil – $1.50

+ metal rod – ?

+ paper – ?

≅ $80.00

solar challenge : progress

The goal of this solar challenge is to keep it simple and stick to the requirements. In my opinion this is a great way to learn various tools that will be extremely useful in the future. The idea is to log small variations of the Earth’s movement and its atmosphere – I don’t even know if this is possible but, considering the size of the data logger and the amount of energy spent to keep this system up using solar power make, I have to say it won’t do any harm having it sit outside for a couple o months, a year maybe, gathering some data of the environment.

To do this challenge I chose to work with two sensors: the UV sensor and the 10-DOF board both from Adafruit. The latter is a combination of four sensors: an accelerometer, a magnet, a gyroscope and a barometric pressure sensor. This will give me plenty of data to work with in the future. To keep track of time (real, global time) I am using a real time clock from Sparkfun, that will allow me to print a date and time tag along with the values logged, and even if the system goes down for a while, this clock has a battery that lasts for 20 years, so, until that time, I’m safe. Lastly, I chose to use a micro SD card break out board (also from Adafruit) as the memory where the data is logged. The main reason I chose this rather than an EEPROM is because it is much more practical to stick the card into a computer than reading from a memory chip, plus, I have 16gb of space.

Right now, I have all sensors, clock and SD card working together, along with the Arduino sketch. Until next week, I shall focus on the solar bit of the challenge: assembling the circuit for the PV – charger – battery. I still need to clean up the code, but it is definitely working as it should.

The circuit – without the SD card board – was drawing 0.03A. I still have to measure how much current the SD will draw, but I expect everything to work well with the 3.7V 1.5A battery I have. And I still need to explore the JeeLab library!

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Bk VIII:183-235 Daedalus and Icarus

Meanwhile Daedalus, hating Crete, and his long exile, and filled with a desire to stand on his native soil, was imprisoned by the waves. ‘He may thwart our escape by land or sea’ he said ‘but the sky is surely open to us: we will go that way:Minos rules everything but he does not rule the heavens’. So saying he applied his thought to new invention and altered the natural order of things. He laid down lines of feathers, beginning with the smallest, following the shorter with longer ones, so that you might think they had grown like that, on a slant. In that way, long ago, the rustic pan-pipes were graduated, with lengthening reeds. Then he fastened them together with thread at the middle, and bees’-wax at the base, and, when he had arranged them, he flexed each one into a gentle curve, so that they imitated real bird’s wings. His son, Icarus, stood next to him, and, not realising that he was handling things that would endanger him, caught laughingly at the down that blew in the passing breeze, and softened the yellow bees’-wax with his thumb, and, in his play, hindered his father’s marvellous work.

When he had put the last touches to what he had begun, the artificer balanced his own body between the two wings and hovered in the moving air. He instructed the boy as well, saying ‘Let me warn you, Icarus, to take the middle way, in case the moisture weighs down your wings, if you fly too low, or if you go too high, the sun scorches them. Travel between the extremes. And I order you not to aim towards Bootes, the Herdsman, or Helice, the Great Bear, or towards the drawn sword of Orion: take the course I show you!’ At the same time as he laid down the rules of flight, he fitted the newly created wings on the boy’s shoulders. While he worked and issued his warnings the ageing man’s cheeks were wet with tears: the father’s hands trembled.

He gave a never to be repeated kiss to his son, and lifting upwards on his wings, flew ahead, anxious for his companion, like a bird, leading her fledglings out of a nest above, into the empty air. He urged the boy to follow, and showed him the dangerous art of flying, moving his own wings, and then looking back at his son. Some angler catching fish with a quivering rod, or a shepherd leaning on his crook, or a ploughman resting on the handles of his plough, saw them, perhaps, and stood there amazed, believing them to be gods able to travel the sky.

And now Samos, sacred to Juno, lay ahead to the left (Delos and Paros were behind them), Lebinthos, and Calymne, rich in honey, to the right, when the boy began to delight in his daring flight, and abandoning his guide, drawn by desire for the heavens, soared higher. His nearness to the devouring sun softened the fragrant wax that held the wings: and the wax melted: he flailed with bare arms, but losing his oar-like wings, could not ride the air. Even as his mouth was crying his father’s name, it vanished into the dark blue sea, the Icarian Sea, called after him. The unhappy father, now no longer a father, shouted ‘Icarus, Icarus where are you? Which way should I be looking, to see you?’ ‘Icarus’ he called again. Then he caught sight of the feathers on the waves, and cursed his inventions. He laid the body to rest, in a tomb, and the island was named Icaria after his buried child.

Hearing The Grass Grow

by João Costa and Jordan Backhus

Out of human sight, there exists an immeasurable, age-old community of intelligent life that helps support and replenish human existence and Earth’s natural resources. Mycelium, the vegetative part of fungus and the fruit of which are mushrooms, form fungal networks that can cover as much as thousands of acres, making particular varieties some of the largest and oldest in the world. In his book “Mycelium Running,” Paul Stamets argues that these microscopic cells may, in part, be responsible for the future of ecological sustainability, variability, and, more importantly, survival. Through mycoremediation, we can capitalize on mycelium’s adaptive digestive capabilities to decompose pollutants and toxic waste; through micro-filtration, we can break down silt from waterbeds and disease-producing agents from agricultural watersheds; through mycopesticides, we can control the populations of insects; and through mycroforestry, we can strengthen the conditions of our gardens and forests. In an attempt to give a “voice” to this overlooked (and underrated) kingdom, we will record, amplify, and showcase the realtime growth of these microorganisms in our own ecological environment. The acoustics will corroborate the presence of this inconspicuous domain, which is otherwise left unheard by human ears. Through a plexiglass wall, the user can watch the mycelium grow over time, forming rich soil by breaking down plant debris and other organic matter; through a speaker, the user can hear the growth of our organisms on the microscopic level.

Though we’ve both experimented with acoustics in our various fields of study, we were entirely new to the art of acoustic ecology. In order to record sound of the atomic sort, one must have both the proper equipment and breadth of scientific information. In our first attempt, we contacted David Dunn from The Acoustic Ecology Institute, whose mission is to increase personal and social awareness of our sound environment. In his soundscape composition “The Sound of Light in Trees: The Acoustic Ecology of Pinyon Pines,” Dunn created a composite aural portrait of the acoustic world inside a pinyon pine. In addition, Dunn was one of the innovators of low-cost microphones for microscopic use (for instance, microphones to record infrasonic sounds in the villages of prairie dogs and omni-directional ultrasonic microphones to record the communications between bats). Unfortunately, our efforts to facilitate a conversation with Mr. Dunn were fruitless. As a result, we continued our research, shifting our inquiries to broader territories, specifically that of nanotechnology. After a few days, we discovered Igor Sokolov, the former Director of Nanoengineering and Biotechnology at Clarkson University and current Professor of Mechanical Engineering at Tufts University. He responded immediately to our first email and kindly (and poetically) reminded us that the idea of “hearing” the grass grow “originated in folk fairy tales.” We knew the fit was right.

In our Skype conversation with Mr. Sokolov, he assured us that listening to mycelium growth was, in fact, entirely possible. In his studies of the atomic particles within insect bodies (specifically mosquitos), Mr. Sokolov found that scanning probe microscopy (SPM) was the most successful. In doing so, he could accurately obtain the frequencies and amplitudes of the vibrations of particles within his specimens. He could then use this information to hand-build a microphone capable of recording and amplifying his findings. “The motion and behavior of a single particle yields information different and complementary to that obtained from an ensemble average of many particles,” Mr. Sokolov explained. By recording the movement and acoustics of insect bodies on the atomic level, the observer can see firsthand how particles (including non-specific neurons) interact and react under certain conditions and external stimuli (including, but not limited to, color, light, and sound). Professor Sokolov asserts that this research gives insight into the innate behaviors of insects, including reflexes, orientation behaviors, kinesis (change in the speed of movement), and taxis (movement towards or away from positive or negative stimuli). As we had hoped, Sokolov encouraged our ambitions: out of human perception, there exists an incredibly enlightening and wonderfully poetic environment of both movement and sound.

Unfortunately, obtaining the proper equipment for scanning probe microscopy (and, furthermore, atomic force acoustic microscopy) is not easy, nor is it cheap. The instruments used for this technique are married to specific university guidelines and are inaccessible for external artistic experimentations, such as ours. Professor Sokolov uses the Laboratory for Nanoenigneering and Biotechnology at Tufts University, as well as university funds for his studies; though he was able to obtain a lot of his recording equipment (for the making of atomic microscopes) on eBay, we recognize that these materials are not easily obtained in perfect working condition after various inquires to eBay sellers. Given the brevity of this class’ semester, we can only expect to create a prototype, in the vision of our original idea, in the hopes that we will be able to continue our research outside of the bounds of the classroom for further interpretation and experimentation. It will take time, money, and various levels of written approval to access the unique apparatuses to measure the frequency and vibrations of mushroom growth; with two week’s time, we have yet to find this atypical information from external studies online or in print. Our prototype will be the framework for our future artistic endeavors.

We too often forget the profundity of simplicity; in the activity of our everyday lives, we are swept in the current, in the ebb and flow, of our complexities and that of those around us. Under the surface, out of human sight, there exists an intelligent, sentient community of organisms with complex communications. Fungus are simple-celled eukaryote organisms with a single nucleus; yet, they remain aware; they react to change; they devise diverse chemical responses to the challenges around them. They are, in fact, our infinitesimal protectors and, out of human sight, they consistently, silently heal the injuries we inflict to our planet. Through our studies of mycology and our discussion of its possibilities, we hope to interest our audiences in educating themselves in the power of fungi in our ecological systems and to remind them that in great simplicity, we find extraordinary complexity, and beauty therein.

Sketches and Prototype:

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Et ignotas animum dimittit in artes « And he turned his mind to unknown arts »

50ft of self expression : tests

This work consists of a receipt thermal printer constantly printing the waveform of the sound it is producing captured by a microphone that, in the final version, will be inside the printer. For test purposes I kept the microphone out of it. In the beginning I was having some trouble adjusting the space between lines, until I started messing around with the library provided by adafruit. It seems pretty satisfying now, and it is quite responsive! I will soon right some paragraphs about this work, but for now, some photos:

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energy final : tests

I started putting together some components to see how the circuit for the final may look like. To begin, I connected the stepper motor to the EasyDriver and Arduino. At first I thought the easy driver wouldn’t be enough to run my motor (400 steps/rev 3V 1.7A) because it can only output 750mA, but surprisingly it worked. Apparently, when using these PWM drivers they’ll take care of the voltage and current, even if it’s a higher voltage, by PWMing the coils. Anyway, below are some pictures of the first test – using a 12V 2A power supply connected to the Vin of the Arduino – and the second test – using the bench power supply I was able to run the whole setup from 5V ~130mA, and still get 3.3V to power the Arduino Mini.