Author: Kris Chen

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Recitation 2 – Kris Chen

In this recitation we made some simple circuits using Arduino Kit.

Fading Light

Tone Melody

Speed Game


Circuit graph for the speed game

The core technology of first circuit is a analog signal output, which can fade the light. Using analog signal to control lights is widely seen in our life, such as the lights on police car and ambulance. There are more advanced application of it. For example, TV signals, in the past are also transmitted using analog signals. The Second circuit is mainly using digital output to control speaker to make certain tones. This technology is also widely used in midi formatted media files. However in another reading in last week we read about musical instruments based on circuits, yet they uses analog input and output. I think only using digital output is not enough for expressing the subtle emotions in the music. The third circuits uses many technologies and ideas from the physical computing reading, such as the idea of interaction, serial input and output. I think there is also parallel computing in this circuit, as the chip will function when two people press the buttons simultaneously.
The reason for using 4k resistor is that: if no resistor in that loop the current will be too high and might destroy the Arduino, burn the wires etc. A 4k resistor with 5V power means I = U /R = 1.25 * 10^-3 A current, which is definitely safe.
If I have 100000 LEDs, I would make a 3D screen, like :

This is a low resolution one. 100000 LED would achieve better solution. With this 3D display device, we can also deploy sensors and AI software to make interaction function between users and the device, for example, one can use their hands to manipulate the 3D image in the devices when they touch the LEDs.

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Week 2: Physical Computing’s Greatest Hits (and misses) & Physical Computing – Introduction, O’Sullivan and Igoe —– Kris

The guideline of physical computer proposed in the book Physical Computing by O’Sullivan and Igoe offers a basic idea of what function and compartments a physical computing device should have.Besides the detailed implementation of physical computing, such as the introduction of using circuit, microcontroller and chips, the core idea of it is still the same as the last reading about interactivity, that is, a device can receive an action, analyze is and give a reaction. Physical computing is much similar to a interactive device. Yet for physical computing, the action it receives and the reaction is gives might be best in reality. I mean not as data flows shown on screen, but real behaviors, like turn off the lights when heard a voice command of a human (a practical one) or play some music notes or draw a stroke on a wall (a more artistic one). In the other reading we can see lots of devices that are based on this idea, while using different hardware. Some of them are already widely applied designs that we might not think them as physical computing of interactive device, such as multitouch interface. Now even a mobile phone’s screen can accepts 10 fingers’ touch simultaneously. Other designs are also interesting, but are far away from us. The music devices are cool but not many people uses them, because their sounds are nevertheless less audible then real musical instruments, as they, after all, uses chip-generated notes. So an improvement of them might be combine the design with real musical instruments. Some of them are more artistic and beautiful such as the field of grass, therefore is a successful physical computing device as well. In general, physical computing can create unique art that cannot be imagined by the past people, different from drawings and music. On the other hand, physical computing can be practically used in daily life and have more down-to-the-earth usage. Both of them are good guidelines for designing our physical computing device.

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Week1: Recitation & Reading

The first Interlab recitation is really exciting. We learned soldering and manipulating electric units.

1. Soldering

Although I’ve soldered before for my robots, there are always something new to learn for me. Before I just tried solder without any professionality. This time I learned the precise step of soldering. During the soldering, I also found some tricks: for example, if I failed to solder two parts directly, I can just use the solder on the iron and plaster them onto the connecting points.


The Button I soldered

1. Making circuits

We made 3 circuits: A speaker; an LED; and a dimmed LED. Unlike many who had trouble with the circuit graph, the most difficult part for me is to use breadboard properly. Even if I learned at class how the wires are connected under the board, I made mistakes during use. For many time I plug in the units horizontally on the board.


The speaker I made



The LED I made

After the recitation I asked my professor Rudi the function of the capacitor, as I didn’t understand why we use it there. Then I learned it is to filter out other voltage to make the power a stable voltage and it must be used to together with the voltage regulator. But I still don’t know how the voltage regulator works and I would like to learn more about it in thte future.

Connection to the reading:

The article offers a model for Interactivity: two actors, each can send, process, and receive information and the operate the process with each other.
For the circuits: we press the button and send the information, the circuits receives it, “process it” and turn on the light/make sounds, then we receive those signals. It ends there. We don’t need to process the information and react. Also, as the author gives an example of that tree branch, It made me wonder the lifeless and unsmart circuit might not be a strong actor itself. So I designed the following model to make the circuit interactive:

We are on a ship, on some ocean and we don’t have phones due to some reason (whether it’s sun storm or we are in 18th century). We found there is a ship not far away on our side and we need to communicate with it (for making sure it’s not enemy or asking for help whatever). We take out our circuits and send out Morse code either by flashing the LED on voice the speaker (well, that should have more power of course). People on the other side received the information, take out their circuits and send the response. Then we talk.
well, that’s interactivity.

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Final Project: Artifical Muscle Based on Electroactive Polymers

Introduction

Our idea come from two perspectives:

1. After the locomotion lab, we realized that although we tried to make robotic arms and legs, we cannot avoid the use of motors, servos and other metallic compartments. Although they seem to function well, they are different from real animal movements. In real world, no animal have this type of rotating body part. Thus, they have certain limitations and drawbacks. As the real animals’ locomotion is driven by muscles, we want to develop real artificial muscles for new foundation of robotic locomotion.

2. We at first want to make a jellyfish floating in the air. Then after research we discovered jellyfish move by propulsion using the muscle in its body.

The muscle expand to create a negative pressure to inhale water, then contract to propel them out. So we shift our focus on developing an artificial muscle.

After research, we focused on a new material: Ionic Polymer-Metal Composites (IPMCs), which is a subset of Electroactive Polymers (EAPs). This kind of material can conduct movements such as shrink and stretch under a low voltage. It can function as artificial muscles for a new foundation of robotics design. Then we researched its property and mechanism, and designed experiment to manufacture it.

EAPs and IPMCs

We researched on the development and mechanism of IPMCs and EAPs:
EAPs is firstly invented by Wilhelm Rontgen. Then in the 1960s, a major breakthrough of EAPs took place, and the first electrically conducting polymers were discovered by Hideki Shirakawa. In the early 1990s, IPMCs were developed and appears to be much more effective compared to EAPs. It needs only 1 or 2 volts to motivate, and this became a significant discovery for the bio-inspired robotics’ development.

We discovered that EAP materials have two categories, Dielectric Electroactive Polymers (DEAP), whose squeezing and stretching behavior is caused by electrostatic forces on the surfaces. The force stretches and squeezes the insulated polymers in the middle. This type of material is resilient and relatively easy to manufacture. However, it requires thousands of volts to function. The other type is Ionic Electroactive Polymers (IEAP), which is represented by IPMCs. The material is made up of an cation or anion exchange polymer with its two sides plated by metals. When being added voltages, the surfaces creates an electric field in the polymer, moving the corresponding ion to one side. However, the detailed theory behind its behavior is not fully understood.

However, the artificial muscle made of IPMCs is still hard to be manufactured, and the quality of the material is still beyond control. Thus, base on previous research done by other scientists, we want to find a simple procedure for common students to produce their own artificial muscle from EAPs, and find ways to apply this new kind of artificial muscle to the bio-inspired robotics.

Manufacturing Procedure

we studied various materials including PDMS, Nafion, Platinum, Carbon. After thourough research, we discovered Nafion 117 and Platinum is a great material combination for making IPMCs.

The structure of Nafion 117

We decided to use NaBH4 to reduce Pt ion to nanometer scale Pt metal particles after we let Pt ion sink into the polymer, based on the formula:

NaBH4 + 4Pt2+ +8OH− ⇒ 4Pt + 16NH3 + NaBO2 + 6H2O.

Below are the manufacturing guide proposed by us based on research and experiment:

Material Preparation
Equipment: Beaker, Glass Rod, Dropper, Test Tube, Forceps, Water Bath, pH test paper.
Reagents: 10cm x 10 cm Nafion-117 Polymer, Platinum standard solution, diluted hydrochloric acid, 1% ammonium hydroxide solution, 10% NaBH4

Manufacturing
1. Cut Nafion-117 into 2 x 1cm x 5cm, 2 x 2cm x 5cm, 2x 1cm x 10cm, 1 x 2cm x 10cm.
2. Roughen the surface of Nafion-117 polymer by sandpapering.
3. Mix Pt solution with ammonium hydroxide until pH is 3.
4. Place the one cut of the polymer in the stirring Pt solution at 80◦C for 5 minutes.
5. Move the polymer to NaBH4 solution at 50◦C, observed bubbles emerge on the polymer. Wait for the reaction to be over.
6. Repeat process 4-5
7. When dense grey metallic layers form on the membrane surface, finish the experiment.


Our lab

Lab Record

First Experiment:

To test what is the best pH for Pt solution, we first made the pH = 6, yet a unexpected reaction happened and precipitate most Pt ion.

high pH caused Pt ion, chlorine ion and ammnonium ion to form ammonium chloroplatinate

Then we followed the instruction of a paper to mix Pt solution with NaBH4, which cause more trouble, as the Pt ion in the solution react directly with NaBH4.


The result of mixing Pt solution with NaBH4 together.

First Experiment Result: Failed
Reasons’ Analytic Report:
The previous stirring time is not enough for Pt ions to attach on the surface of the polymer.
The NaBH4 solution was mixed with the Pt solution, which caused waste of the Pt icons in solution.
The concentration of the ammonium hydroxide solution is too high and caused the high pH level of the solution. Finally, it results in the precipitation of Pt.

From it we designed new procedure proposed in the beginning.

Second Experiment:
We follow our procedure clearly and successfully plated Platinum on the polymer. However, we didn’t repeat 4,5 process enough and the nanometer scale Pt scatter loosely on the polymer, which are quickly oxidized after we took it out.


Polymer in Reaction: The bubbles are ammonium.


Polymer plated with nanoscale Pt

Second Experiment Result: Half Success
Reasons’ Analytic Report:
The Pt that was successfully attached to the polymer was oxidized by the oxygen in the open air.
The Pt on the polymer is still not enough after a single round of the experiment. The above procedures need to be repeated 3-5 times to ensure the efficiency of the polymer.

We knew we need to repeat procedure 4 and 5 until a dense layer is formed on the whole surface of Nafion.

Third Experiment

In the last repetition of step 5, we tried reduction agent with higher concentration to accelerate. However the reaction is too violent that the bubbles flushed all Pt particles down to the bottom of the test tube.


Too violent reaction

Third Experiment Result: Half Success
Reasons’ Analytic Report:
Try to use a higher concentration of NaBH4 solution, however it turned out to be too much and the Pt that had already attached on the surface in previous steps, drop down.
The time is so limited that the reaction is not fully completed.

Fourth Experiment: Succeed!

We used hydrazine sulfate as reduction agent this time and we applied it in a very diluted solution with a very long reaction time (almost 12 hours).

The contraction is very slight because it is a air test. The material performs better in solution base. Yet it is easier to take photos and observe it in air.

…

This material can act as a new foundation for robot locomotion system design. We have studied several feasible applications:

1 Heart, Lung, and Jellyfish:
Heart, lung and the propulsion locomotion of jellyfish are similar: the muscle expands, creating a negative pressure to draw in blood, air or water, then the muscle contracts to push them out. They can be implemented by our material.
Using the IPMCs based artificial muscle as the jellyfish’s muscle underwater. The Microbit and related editor like mu-editor can be used to do the physical computing part and provide periodical voltage. The basic movement like moving forward and blood cycle can be achieved by applying different intensity of electric field.

2 Arms, Legs, and Bio-Inspired Seahorse Robotic:
The Seahorse Robotic might be the best robotic to fully utilize the feature of IPMCs based artificial muscle. By using the IPMCs with less Pt density to build the top half part of the seahorse robotic and use the more Pt density one to build the bottom half. The IPMCs’ feature of having different shrinking and stretching level under different Pt density and electric field intensity. It is similar with robotic arms and legs, where the IPMCs connects with to bones, which are assembled by a joint. (From our paper)

Paper link:

https://docs.google.com/document/d/14qt9JRaHoY7bswd0Ce1aVMzVlq7tvD74nGl1PTJUozk/edit?usp=sharing

NYU account login need to open the link and track our progress.

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Lab Report: Swarm Behavior

Plan

Project Description

After discussion, we decided to implement a intelligent clustering behavior among robots. The swarm will calculate the shortest distance among the distances between each two robots. Then the two which the shortest distance will gather together first and become a group to act as a single robot. This process will repeat until all the robots are clustered.

Equipment and sources

Hardware:

Microbit x 5
Robotbit set x 4 (optional)
HD 920c Logitech camera
Aruco markers

Software:

Aruco marker detection software
Serial communication module between laptop and microbit
Microbit wireless communication module
Locomotion module

Modelling

We decided to use a camera on the celling. It will take dynamically measuring the special identification cards stuck on each robot’s back, which, after computation, can show the robots’ coordinates as well as the angle their heads point.[1]

Then the instruction is send to one of the robot in the two [2]. It will first turn until the head faces the other robot; then it will move forward until it is in a certain range with the other one [3]. The two then form a group to repeat the process.

1. The codes and hardware for image recognition part is already provided. The Aruco marker is a asymmetric square picture made up of small black and white squares. Each Aruco marker is unique. The camera set a 0 coordinate and use pattern match AI to get the location of each marker. The asymmetry enables the algorithm to analyze the angle.

2. We programmed a microbit and connect it to a laptop. It will receive the serial message send from laptop command line and repost it via wireless UDP communication to the target microbit.

3. After receiving instructions, the robot will act as coded. at the same time, the camera keeps observing and updating the information. So the robot will change its behavior when necessary.

Code

Published on GitHub:
https://github.com/krawc/arUco
https://github.com/todocono/arUco
https://github.com/todocono/birs2019s

Reflection

The swarm behavior is more difficult then it seems to be. And we learned a lot. As the robot cannot really self organize and handle different exceptions as real humans do. We have to consider and program every detailed case. For example, the first time when two robot gather, they faces different directions, so they cannot move together to find the third robot. It reminds me of the swarm intelligence paper read in class. In the paper, the math formulas didn’t directly describe motions and behaviors; but they set a structure of goals, errors, states, changes etc. which is more fundamental then behavior. I think it is where our improvement and research should focus on if we want to further implement swarm behavior.