Recently, I am working for the project using Greengrass as a deployment solution.

AWS Greengrass is quite an early development phase, there are lots of cool new features are coming, but not yet available.

Here are some minor tips I found while I am building the service when I face some problems. (I will keep updating time by time my project progressing.) 

A Greengrass group cannot have more than one core.

Currently, you can see the CreateCoreDefinitionVersionRequest is you can see the CreateCoreDefinitionVersionRequest is accepting List<Core> as an input parameter, but this is just for future scalable, it does not support yet. It accepts only a single core now.

Greengrass Deployment Stuck In Progress

I created a group and a core using the console, and deploy something, and faced issues of deployments. Mainly the reasons are: When GG cannot communicate through MQTT, or the core daemon is not running.

So mostly I solved this by checking the core Greengrass config is correctly set (/greengrass/config/config.json), whether EC2 (or pi) network security group inbound rule has MQTT 8883 port open, and checking subscriptions between cloud and lambda, and restart the core daemon, and etc.

While you are building provisioning service using APIs, sometimes you mix-use with the console to delete resources like groups, cores, certificates. Because of that, sometimes there is a zomebie-like group showing in the console, for example,  So I removed core definition using API. After that, I got the same error like "This group is currently deployed so it cannot be deleted."

In this case, you should run "reset deployment" (if it does not work, run it with "force" option.) then you can delete the group. 

Visualization 논문 리뷰 작업 중에 논문을 유형별로 나눌 필요성이 느껴져서 찾다가, 블로그에 정리해 두면 좋을거 같아서 IEEE VIS 2015 학회에 정의된 논문 제출 가이드라인 일부를 그대로 영문 번역하였다. 발번역임. (VAST 2016 에서 약간 수정된 논문 타입을 정의하였기에 추가 번역하였음.)

http://ieeevis.org/year/2015/info/call-participation/paper-submission-guidelines

http://ieeevis.org/year/2016/info/call-participation/vast-paper-types

VAST 2016 Paper Types

VAST에는 TVCG 트랙과 Conference-only 트랙, 두개의 트랙이 있는데, 각 트랙은 서로 다른 레벨의 originality, rigor, 그리고 significance를 가진다.  보통 VAST 논문들은 다른 두 VIS 학회 - InfoVIS, SciVIs - 의 논문들처럼 상세한 접수 가이드라인에 따라 작성, 접수, 리뷰의 과정을 거친다. 그러나, visual analytics의 빠른 과학, 기술, 응용의 발전에 따라, 수시로 VAST 출판물에 대한 이해도를 조정하는 것이 현명하다. 기존 5개 형식의 논문 타입에 대한 논의는 뒤로 하고, 아래에 VAST 2016의 논문 타입에 대해 명시하였다. 

Visual analytics, concepts, theories, algorithms, techniques, designs, systems, empirical studies 와 applications 는 일반적으로 분석, 시각화, 상호작용이 인간과 기계간 조화를 최적화 하도록 통합되는 곳에 컨텍스트를 생성한다. 이 컨텍스트는 VIS의 다른 학회들과 차별된다: 데이터가 spatial 인지 non-spatial인지, 기술들이 human-centric 인지 machine-centric 인지, application domain 이 대부분  any academic discipline, industry, business sector, 혹은 governmental operation 인지. 이러한 맥락에서, 개개의 VAST 논문은 새로운 기여가 존재하는 곳에 강하게 포커스를 맞추거나 다른 측면의 통합을 강조한다.

VAST has two tracks, TVCG and Conference-only tracks, which correspond to different levels of originality, rigor, and significance. In general, VAST papers should be written, submitted and reviewed in the same way as papers at the other two VIS conferences (i.e., InfoVis and SciVis), following the detailed submission guidelines. However, with the rapid development of the science, technology and application of visual analytics, it is sensible to adjust our understanding of VAST publications from time to time. We provide the following clarifications about paper types for VAST 2016, beyond the discussion of the five paper types in the shared guidelines.

In visual analytics, concepts, theories, algorithms, techniques, designs, systems, empirical studies and applications normally create a context where analysis, visualization and interaction are integrated to optimize the combination of human and machine capabilities. It is this context that differentiates VAST from other conferences in VIS, while data involved can be spatial or non-spatial, techniques can be human-centric or machine-centric, and the application domain can be almost any academic discipline, industry, business sector, or governmental operation. Within such a context, an individual VAST paper may give a strong focus on an aspect where novel contributions reside, or place its emphasis on the integration of different aspects.

VAST 논문은 일반적으로 6개의 카테고리로 분류된다:

1. 이론과 모델

2. 기술과 알고리즘

3. 디자인 연구

4. 실증 연구 (기존 가이드에서 Evaluation 형태로 분류되는 논문들.)

5. 시스템

6. 응용 (Design Study 에서 별도로 분류된 카테고리.)

Theory and Model

Fundamentals of visual analytics. Conceptual understanding and modelling of visual analytics (e.g., definitions, taxonomies, analytic frameworks, and research methods, etc.). Philosophical and sociological discourses of visual analytics (e.g., human vs machine, ethics, data security, uncertainty, biases, and privacy, etc.). Perception and cognition in visual analytics.

Mathematical abstraction and modelling of visual analytics processes. Concepts and models that govern quality metrics and benchmarks for evaluating visual analytics processes and systems.

Examples:

Megan Monroe, et al. "Temporal event sequence simplification." VAST 2013 Honorable Mention.

Technique and Algorithm

Visualization techniques in visual analytics processes. Close integration of technical components of visual analytics (e.g., statistical analysis, human-defined and machine-learned algorithms, knowledge representations, visualization/interaction techniques and methodologies, etc.) for supporting visual data mining.

Visual analytics for supporting the advancement of non-visual technical components of visual analytics (e.g., visual analytics for supporting model development, simulation, learning, monitoring, and optimization).

Integrated data acquisition, management, retrieval, processing and transformation in visual analytics (e.g., multi-sources; multi-resolution; data provenance; uncertainty; real world measures; textual, audio, visual and other media; factual, statistical, semantic, synthesized, and hypothesized data; etc.). 

VA techniques for spatial and non-spatial data, temporal data, streaming data, quantitative and qualitative data, text and document data, and so on. Techniques for production, presentation, and dissemination of VA results.

Examples:

Thomas Muhlbacher and Harald Piringer. “A Partition-based framework for building and validating regression models.” VAST 2013 Best Paper.

Stef van den Elzen et al. “Reducing snapshots to points: a visual analytics approach to dynamic network exploration.” VAST 2015 Best Paper.

Empirical Study

Understanding human-centric components in visual analytics processes (e.g., perception, cognition, interaction, communication, collaboration, etc.).

Understanding human capabilities and limitations in data intelligence (e.g., exploration, navigation, sensemaking, context awareness, knowledge discovery, learning, argumentation, causality reasoning, accountability, biases, etc.).

Understanding visual signatures in data intelligence (e.g., patterns of clusters, patterns of anomalies, etc.).

Understanding the potential merits and demerits of technologies in visual analytics (e.g., display technologies, interactive technologies, automated analytics, crowdsourcing analytics, and so on).

Human-centric comparative studies on aspects of visual analytics (e.g., visual representations, interaction techniques, active learning, visual analytics literacy, requirements analysis, etc.).

Evaluation methodologies for visual analytics techniques and systems in real world environments.

Different quantitative and qualitative (including ethnographic) forms of empirical studies (e.g., lab-based studies, field studies, crowdsourcing, group discussions, surveys, interviews, user experience observation, shadowing, case studies and casebook construction, etc.)

Transformation of scenarios and data captured in studies to benchmark problems and data-driven metrics.

Examples:

Narges Mahyar and Melanie Tory. "Supporting communication and coordination in collaborative sensemaking." VAST 2014 Best Paper. 

Hua Guo et al. "A case study using visualization interaction logs and insight metrics to understand how analysts arrive at insights." VAST 2015 Honorable Mention.

Design Study

Designing disseminative visual analytics (e.g., storytelling, illustration and animation, public engagement, etc.)

Designing observational visual analytics (e.g., multivariate data, streaming data, multimedia data, geospatial data, spatio-temporal, etc.)

Designing analytical visual analytics (e.g., clustering, anomaly detection, association and network analysis, correlation, causality, uncertainty, etc.)

Designing model-developmental visual analytics (e.g., exploring parameter space, and model space, supporting dimensionality reduction and machine learning, model-developmental life cycle, etc.)

Design methodologies for real world visual analytics systems and users.

Examples:

Jian Zhao et al. "#FluxFlow: Visual analysis of anomalous information spreading on social media." VAST 2014 Honorable Mention.

System

Methodologies for engineering real world visual analytics systems.

System platforms (from wearable devices to desktops to large infrastructures, and from architectures and software libraries (toolkits), to stand alone systems and apps, to online services and open source repositories).

Comparative studies on real world visual analytics systems.

Development tools for the software lifecycle of visual analytics systems, including requirements analysis, system specification, system design, system implementation, system testing, user evaluation, and system maintenance).

Addressing challenges in real world visual analytics systems (e.g., provenance management, scalability, uncertainty, open testbeds, etc.).

Automation, customization, and personalization, and interoperability.

Best practices (e.g., interoperability, workflow design, cost-benefit analysis, standardization, etc.)

Examples:

Tanja Blascheck et al. "VA2: A visual analytics approach for evaluating visual analytics applications." VAST 2015 Honorable Mention.

Application

Delivering visual analytics solutions to applications in academic disciplines (e.g., physical sciences, biological and medical sciences, engineering sciences, social sciences, arts and humanities, and sports sciences).

Delivering visual analytics solutions to applications in industries and governance.

Delivering visual analytics solutions to applications in public services and entertainment (e.g., resilience, healthcare, transport, sports, tourism, broadcasting, and social media).

Examples:

Conglei Shi, et al. "LoyalTracker: Visualizing loyalty dynamics in search engines." VAST 2014 Honorable Mention.

VIS 2015 Paper Types

VIS 논문의 유형은 대게 5개 카테고리로 나누어진다: technique, system, design study, evaluation, or model. 이 카테고리들에 대해 아래에 간단히 설명하였다. 논문 유형은 논문 제출 과정 중에 정해지긴 하지만, 한개 이상의 카테고리를 가질 수 있다. "Process and Pitfalls in Writing Information Visualization Research Papers" by Tamara Munzner 를 참고하여 어떻게 VIS 논문을 잘 쓸 수 있는지 참고하라. 

A VIS paper typically falls into one of five categories: technique, system, design study, evaluation, or model. We briefly discuss these categories below. Although your main paper type has to be specified during the paper submission process, papers can include elements of more than one of these categories. Please see "Process and Pitfalls in Writing Information Visualization Research Papers" by Tamara Munzner for more detailed discussion on how to write a successful VIS paper.

Technique 눈문

이 유형의 논문은 해당 학계에서 이전에 본적 없던 새로운 기술(techniques)이나 알고리즘을 소개하거나, 기존 기술과 알고리즘을 현저하게 발전시킨 경우로, 예를 들어 이전보다 훨씬 큰 데이타셋으로 확장하거나 더 많은 방면으로 사용하게 되는 기술로 일반화 하는 경우이다. 기술이나 알고리즘의 상세 설명이 완전히 제공되어서 실력을 갖춘 대학원생이 이를 구현할 수 있어야 하고, 저작자는 프로토 타입 구현물을 만들어야 한다. 관련 이전 논문 참조가 반드시 있어야 하고, 이전 방법을 뛰어넘는 새로운 방법의 장점이 명백하게 기술되어야 한다. 이 새 방법이 적절한지, 제한이 있는지에 대해 작업과 데이타셋의 논의가 필요한다.  비공식 또는 공식적인 user studies 나 다른 방법을 통한 평가(Evaluation)는 논문을 더 탄탄하게 만들어 주지만,  필수사항은 아니다.

Technique papers introduce novel techniques or algorithms that have not previously appeared in the literature, or that significantly extend known techniques or algorithms, for example by scaling to datasets of much larger size than before or by generalizing a technique to a larger class of uses. The technique or algorithm description provided in the paper should be complete enough that a competent graduate student in visualization could implement the work, and the authors should create a prototype implementation of the methods. Relevant previous work must be referenced, and the advantage of the new methods over it should be clearly demonstrated. There should be a discussion of the tasks and datasets for which this new method is appropriate, and its limitations. Evaluation through informal or formal user studies, or other methods, will often serve to strengthen the paper, but are not mandatory.

System 논문

이 유형의 논문은 알고리즘, 기술적 요구사항, 사용자 요구사항, 설계 등을 융합하여 주요 문제를 풀어낸다. 제시된 System 은 새롭고 중요한 것으로서, 구현 된 것으로 여겨진다. 중요한 설계 결정을 위한 이론이 뒷받침 되고, 문서화 되어 이미 사용중인 동종 최고의 시스템과  비교되어진다. 이 비교에는 몇 가지 중요한 측면에서 이 시스템이 다른 시스템들과 어떻게 다른지, 그리고 무엇이 우수한지에 대한 구체적인 논의가 포함된다.  예를 들어, 기술된 시스템은 시각화(visualization) 시스템의 성능이나 사용성에서 상당한 우수성이나 새로운 가능성을 제공할 수도 있다. 외부적인 요소들은 (프로세서 성능, 메모리 크기, 혹은 OS의 기능면에서의 향상 등) 이러한 비교에 영향을 미치므로 가능한 모두 제거해야 한다.  추가 제안으로는, "How (and How Not) to Write a Good Systems Paper" by Roy Levin and David Redell 과  "Empirical Methods in CS and AI" by Toby Walsh 를 훑어볼 것을 권장한다. 

System papers present a blend of algorithms, technical requirements, user requirements, and design that solves a major problem. The system that is described is both novel and important, and has been implemented. The rationale for significant design decisions is provided, and the system is compared to documented, best-of-breed systems already in use. The comparison includes specific discussion of how the described system differs from and is, in some significant respects, superior to those systems. For example, the described system may offer substantial advancements in the performance or usability of visualization systems, or novel capabilities. Every effort should be made to eliminate external factors (such as advances in processor performance, memory sizes or operating system features) that would affect this comparison. For further suggestions, please review "How (and How Not) to Write a Good Systems Paper" by Roy Levin and David Redell, and "Empirical Methods in CS and AI" by Toby Walsh.

Application / Design Study 논문

이 유형의 논문은 한 응용분야에서 시각화나 시각 분석 기술을 적용할 때 발생되는 선택 사항들을 탐구한다. 예로, 대상 업무의 요구사항에 대한 상호작용 기술들과 시각적 인코딩 등을 들 수 있다. 유사하게, Application 논문은 공학 과학 문제들에 대한 통찰들을 모으기 위해 사용되는 시각화 기술들을 설명할 때, 표준으로 사용되어져 왔다. 그럼에도 불구하고 상당한 양의 도메인 배경 지식 application이 목적 업무의 상세사항을 논하는 콘텍스트의 프레이밍을 제공함에도 불구하고, case study의 주요 초점은 시각화 내용이어야만 한다. 응용 도메인에서 생성된 통찰들을 포함한 Application/Design Study 논문의 결과물들은 분명하게 전달되어야 한다. 당면한 문제를 풀기위한 새로운 기술과 알고리즘을 기술하는 것은 design study 논문을 강화하지만, Technique 논문만큼 참신함이 크게 요구되어지진 않는다. 필요할 시, 기본적인 파라메트릭 스페이스와 그것의 효과적인 검색에 대해 적절한 설명으로 밝혀야 한다. 

Application / Design Study papers explore the choices made when applying visualization and visual analytics techniques in an application area, for example relating the visual encodings and interaction techniques to the requirements of the target task. Similarly, Application papers have been the norm when researchers describe the use of visualization techniques to glean insights from problems in engineering and science. Although a significant amount of application domain background information can be useful to provide a framing context in which to discuss the specifics of the target task, the primary focus of the case study must be the visualization content. The results of the Application / Design Study, including insights generated in the application domain, should be clearly conveyed. Describing new techniques and algorithms developed to solve the target problem will strengthen a design study paper, but the requirements for novelty are less stringent than in a Technique paper. Where necessary, the identification of the underlying parametric space and its efficient search must be aptly described. The work will be judged by the design lessons learned or insights gleaned, on which future contributors can build. We invite submissions on any application area.

Evaluation 논문

이 유형의 논문은 사람에 의한 시각화와 시각적 분석의 사용을 탐구하고, 일반적으로 시각화 기술이나 시스템의 경험기반 연구가 제공된다. 저작자는 이러한 스터디가 자체적으로 사용되어지는 시스템을 구현할 필요는 없다; 연구의 기여도는 연구중인 시스템 또는 기술의 참신함과는 반대로 유효성과 경험적으로 얻은 결과의 중요성에 의해 평가된다. 학회의 커미티는 엄격한 실험을 설계하고 수행하는 중요성과 어려움을 높이 평가한며, 적절한 가설(hypotheses), 업무, 데이타셋, 대상의 선택, 측정, 유효성과 결론 등에 대한 것들이 포함된다. 이러한 노력은 실험에 대한 단순 기술보다는 예측과 설명을 목표로 한다. 인간을 대상으로 하는 실험의 설계에 익숙하지 않은 저작자는, 엄격한 경험적 프로토콜의 설계와 결과자료의 통계적 분석에 경험이 있는 심리학이나 human-computer 상호작용 영역의 동료를 원할 수 있다. 다른 새로운 형태의 evaluation 또한 권장된다.

Evaluation papers explore the usage of visualization and visual analytics by human users, and typically present an empirical study of visualization techniques or systems. Authors are not necessarily expected to implement the systems used in these studies themselves; the research contribution will be judged on the validity and importance of the experimental results as opposed to the novelty of the systems or techniques under study. The conference committee appreciates the difficulty and importance of designing and performing rigorous experiments, including the definition of appropriate hypotheses, tasks, data sets, selection of subjects, measurement, validation and conclusions. The goal of such efforts should be to move from mere description of experiments, toward prediction and explanation. We do suggest that potential authors who have not had formal training in the design of experiments involving human subjects may wish to partner with a colleague from an area such as psychology or human-computer interaction who has experience with designing rigorous experimental protocols and statistical analysis of the resulting data. Other novel forms of evaluation are also encouraged.

Theory/Model 논문

이 유형의 논문은 시각화와 시각적 분석에 대한 기초적 이론의 새로운 해석을 제시한다. 구현은 보통 이러한 논문과는 연관이 없다. 논문은 어떻게 시각화 기술이 보완되고 인간의 시각과 인지의 요소들을 활용하는지에 대한 우리의 이해 속에서 기본적인 발전성에 초점을 맞춰야 한다. 

Theory/Model papers present new interpretations of the foundational theory of visualization and visual analytics. Implementations are usually not relevant for papers in this category. Papers should focus on basic advancement in our understanding of how visualization techniques complement and exploit properties of human vision and cognition.

LEGO Wall-E Motorized using Arduino

controlling by iPhone

기말고사 기간에 레고 월E 출시 발견. 이어서, 마인드스톰 추가 구성해서 움직이게 한거 보고 넋이 나감. 

그래서 겨울 방학때 아래의 미션하에 프로젝트를 진행하였다:

1. 레고 월E 굴러가게 하기.

2. 무조건 내 핸드폰 앱으로 컨트롤 가능해야 함. 적외선 컨트롤러 이딴거 난 안쓴다.

3. 블루투스 구성 위한 마인드스톰 오지게 비쌈. 아두이노 사용해서 경비절감.

그리하여 아래와 같이 완성!

* 외국 친구들한테도 페북 공유하려다보니 못난 영작이 함께 들어갑니다. 리딩 흐름에 방해가 되더라도 양해 부탁드립니다.

During the last final's week, I found the LEGO's brand-new Wall E model. And soon after that, I found another Youtube video Wall-E motorized with LEGO mind storm. It was totally mind blowing work!! So, of course, I've done this project during my winter break. My missions were:

1. LEGO Wall-E Motorized

2. It has to be controlled by my iPhone. I don't wanna talk about the stupid infrared controller at all. :P

3. But, mind storm for bluetooth is freakin' expensive. Use Arduino.

At the end, voila.

* 기타 제작 과정에서 도움 받은 참고 자료 및 사이트 Additional useful references. 

LEGO Wall-E 21303 Motorized with Power Functions https://youtu.be/3_9q6RjB5nM

Controlling LEGO DC motor with an Arduino https://youtu.be/PtinpaVpHeo

IPhone to Arduino using Bluetooth 4.0 http://www.instructables.com/id/IPhone-to-Arduino-using-Bluetooth-40-/

Core Bluetooth Programming Guide https://developer.apple.com/library/...

Bluetooth 4.0 datasheet http://www.pridopia.co.uk/pi-doc/BT4.0-HM-10-Serial_Port_BLE_Module_Master_Slave.pdf

* 아두이노 모터 제어 코드 Arduino motor control code.

Note 1:  모든 DC 모터는 조금씩 베이스 속도가 다르다. 이를 동일하게 맞추려면 휴리스틱한 방법으로, 두 모터의 속도 스케일 차이를 파악한 후 속도를 조정해야 한다. 뭔 말이냐면, 1번과 2번 모터를 모두 속도 10으로 맞추었는데, 육안으로 봤을때 2번 모터가 1번보다 3배 빠르게 돌아가고 있다면, 구동전에 1번 모터 속도를 30으로 2번 모터 속도를 10으로 맞추고 구동을 한다는 말이다. 

Note 2: 레고 모터는 AFMotor 라이브러리를 이용한 속도 세팅 시, 90 이하의 속도 세팅에서는 아예 구동하지 않는다.

#include <SoftwareSerial.h>

#include <AFMotor.h>

#define SPD1  100                    // Motor1 base speed.

#define SPD2  165                    // Motor2 base speed.

AF_DCMotor motor1(1);            // Motor1 is connected to slot 1.

AF_DCMotor motor2(4);          // Moter2 is connected to slot 4. 

SoftwareSerial BTSerial(3, 2);  // Pin3 is for TX, and Pin 2 is for RX.

int cmd1 = RELEASE;

int cmd2 = RELEASE;

int unavailableCount = 0;

String cmds = "";

void setup()

{

  Serial.begin(9600);

  BTSerial.begin(9600);

  Serial.println("Jisun's Wall-E world!!");

  motor1.setSpeed(SPD1);

  motor2.setSpeed(SPD2);

}

void loop()

{

  if(BTSerial.available())

  {

    char cmd = BTSerial.read();

    cmds = cmds + cmd;

    unavailableCount = 0;

  }

  else

  {

    unavailableCount = unavailableCount + 1;

  }

  if ( unavailableCount > 10 && cmds.length() > 0 )

  {

    int spd1 = SPD1;

    int spd2 = SPD2;

    String dbgstr = "";

    if ( cmds.indexOf("speed") >=0 )

    {

      int spdlv = 1;

      if ( cmds == "speed1") spdlv = 1;

      else if ( cmds == "speed2") spdlv = 2;

      else if ( cmds == "speed3") spdlv = 3;

      spd1 = spd1 + spdlv * 25;

      spd2 = spd2 + spdlv * 20;

      dbgstr = "Set speed level: " + String(spdlv);

      motor1.setSpeed(spd1);

      motor2.setSpeed(spd2);

    }

    else if ( cmds == "forward" )

    {

      dbgstr = "Move forward";

      cmd1 = FORWARD; cmd2 = FORWARD;

    }

    else if ( cmds == "backward" )

    {

      dbgstr = "Move backward";

      cmd1 = BACKWARD; cmd2 = BACKWARD;

    }

    else if ( cmds == "left")

    {

      dbgstr = "Turn left";

      cmd1 = RELEASE; cmd2 = FORWARD;

    }

    else if ( cmds == "right")

    {

      dbgstr = "Turn right";

      cmd1 = FORWARD; cmd2 = RELEASE;

    }

    else if ( cmds == "leftback")

    {

      dbgstr = "Turn left backward";

      cmd1 = RELEASE; cmd2 = BACKWARD;

    }

    else if ( cmds == "rightback")

    {

      dbgstr = "Turn right backward";

      cmd1 = BACKWARD; cmd2 = RELEASE;

    }

    else if ( cmds == "release" )

    {

      dbgstr = "Release";

      cmd1 = RELEASE; cmd2 = RELEASE;

    }

    if ( dbgstr.length() > 0 )

    {

      dbgstr += "(" + String(spd1) + "/" + String(spd2) + ")";

      Serial.println(dbgstr);

      motor1.run(cmd1);

      motor2.run(cmd2);

    }

    else

    {

      Serial.println(cmds);

    }

    cmds = "";

    unavailableCount = 0;

  }

  if(Serial.available())

  {

    char cmd = Serial.read();

    BTSerial.write(cmd);

  }

}

* 아이폰 블루투스 컨트롤러 코드 iPhone bluetooth controller code

ViewController.h

//

//  ViewController.h

//  WallEController

//

//  Created by Jisun Kang on 1/10/16.

//  Copyright © 2016 ___JSK___. All rights reserved.

//

#import <UIKit/UIKit.h>

#import <CoreBluetooth/CoreBluetooth.h>

@interface ViewController : UIViewController <CBCentralManagerDelegate>

@property (nonatomic, strong) CBCentralManager *centralManager;

@property (nonatomic, strong) CBPeripheral *peripheral;

@property (nonatomic, strong) CBCharacteristic *currentcharacteristic;

-(IBAction) goToSecondView:(id)sender;

-(IBAction) cancelConnection:(id)sender;

@end

@interface SecondViewController : UIViewController

@property (nonatomic, strong) CBCentralManager *centralManager;

@property (nonatomic, strong) CBPeripheral *peripheral;

@property (nonatomic, strong) CBCharacteristic *currentcharacteristic;

-(IBAction) pressButtons:(UIButton *)sender;

@end

ViewController.m

//

//  ViewController.m

//  WallEController

//

//  Created by Jisun Kang on 1/10/16.

//  Copyright © 2016 ___JSK___. All rights reserved.

//

#import "ViewController.h"

// this is for various device screen size.

#define SCREEN_WIDTH [[UIScreen mainScreen] bounds].size.width

#define SCREEN_HEIGHT [[UIScreen mainScreen] bounds].size.height

@interface ViewController () <UITableViewDataSource, UITableViewDelegate>

{

    NSMutableArray* cbArray;

}

@property (strong, nonatomic) IBOutlet UITableView *mainTableView;

@property (strong, nonatomic) IBOutlet UILabel *mainLabel;

@end

@implementation ViewController

- (void)viewDidLoad {

    [super viewDidLoad];

    // initializing UITableView

    cbArray = [NSMutableArray array];

    _mainTableView.delegate = self;

    _mainTableView.dataSource = self;

    _mainTableView.backgroundColor = [UIColor colorWithRed:236.0/255.0 green:236/255.0 blue:236.0/255.0 alpha:0.7];

    _mainTableView.backgroundView = nil;

    _mainTableView.allowsMultipleSelectionDuringEditing = NO;

    _mainTableView.separatorStyle = UITableViewCellSeparatorStyleSingleLineEtched;

    _mainTableView.autoresizingMask = UIViewAutoresizingNone;

    self.centralManager = [[CBCentralManager alloc] initWithDelegate:self queue:nil];

    self.peripheral.delegate = self;

}

- (void)viewDidAppear:(BOOL)animated {

    [super viewDidAppear: true];

    _mainLabel.text = @"";

}

- (void)didReceiveMemoryWarning {

    [super didReceiveMemoryWarning];

}

- (void)dealloc

{

    [self.centralManager stopScan];

}

- (IBAction)goToSecondView:(id)sender {

    UIStoryboard *mainStoryboard = [UIStoryboard storyboardWithName: @"Main" bundle:nil];

    SecondViewController* secVC = [mainStoryboard instantiateViewControllerWithIdentifier:@"SecondView"];

    secVC.centralManager = self.centralManager;

    secVC.peripheral = self.peripheral;

    secVC.currentcharacteristic = self.currentcharacteristic;

    [self presentViewController:secVC animated:YES completion:nil];

}

- (IBAction)cancelConnection:(id)sender {

    if ( self.peripheral == nil )

        return;

    _mainLabel.text = @"Cancel connection.";

    [self.centralManager cancelPeripheralConnection:self.peripheral];

    self.peripheral = nil;

    [self.centralManager scanForPeripheralsWithServices:nil options:nil];

}

// =========================================

// CB Central Manager

// =========================================

// Invoked when the central manager’s state is updated.

- (void)centralManagerDidUpdateState:(CBCentralManager *)central

{

    switch (central.state) {

        case CBCentralManagerStatePoweredOn:

            NSLog(@"CoreBluetooth BLE hardware is powered on and ready");

            _mainLabel.text = @"Scanning...";

            [self.centralManager scanForPeripheralsWithServices:nil options:nil]; //@{CBCentralManagerScanOptionAllowDuplicatesKey:@YES}];

            break;

        case CBCentralManagerStatePoweredOff:

        case CBCentralManagerStateResetting:

        case CBCentralManagerStateUnauthorized:

        case CBCentralManagerStateUnknown:

        case CBCentralManagerStateUnsupported:

        default:

            NSLog(@"CoreBluetooth BLE hardware is powered off or not initialized.");

            break;

    }

}

// add the device to our array and reload the table view.

- (void)centralManager:(CBCentralManager *)central didDiscoverPeripheral:(CBPeripheral *)peripheral advertisementData:(NSDictionary *)advertisementData RSSI:(NSNumber *)RSSI

{

    CBPeripheral* currentPer = peripheral;

    if(![cbArray containsObject:currentPer])

    {

        [cbArray addObject:currentPer];

    }

    [_mainTableView reloadData];

}

- (void)centralManager:(CBCentralManager *)central didConnectPeripheral:(CBPeripheral *)peripheral

{

    NSLog(@"Success to connect.: %@",peripheral);

    _mainLabel.text = @"Success to connect.";

    peripheral.delegate = self;

    if (peripheral.services) {

        [self peripheral:peripheral didDiscoverServices:nil];

    } else {

        [peripheral discoverServices:nil];

    }

    self.peripheral = peripheral;

}

- (void)centralManager:(CBCentralManager *)central didDisconnectPeripheral:(CBPeripheral *)peripheral error:(NSError *)error {

    NSLog(@"Disconnected with peripheral: %@",peripheral);

    _mainLabel.text = @"Disconnected and scanning...";

    self.peripheral = nil;

    [self.centralManager scanForPeripheralsWithServices:nil options:nil];

    NSLog(@"The error is: %@", error.localizedDescription);

}

- (void)centralManager:(CBCentralManager *)central didFailToConnectPeripheral:(CBPeripheral *)peripheral error:(NSError *)error

{

    NSLog(@"Connection failed to peripheral: %@",peripheral);

    _mainLabel.text = @"Fail to connect.";

}

- (void)peripheral:(CBPeripheral *)peripheral didDiscoverServices:(NSError *)error

{

    for (CBService *service in peripheral.services)

    {

        NSLog(@"Discovered service %@", service);

        _mainLabel.text = @"Discovered service.";

        [peripheral discoverCharacteristics:nil forService:service];

    }

}

- (void)peripheral:(CBPeripheral *)peripheral didDiscoverCharacteristicsForService:(CBService *)service error:(NSError *)error

{

    NSLog(@"Looking for Characteristic...");

    for (CBCharacteristic *characteristic in service.characteristics)

    {

        if ( characteristic.properties & CBCharacteristicPropertyWriteWithoutResponse )

        {

            NSLog(@"Find Characteristic!!");

            self.currentcharacteristic = characteristic;

            [peripheral setNotifyValue:YES forCharacteristic:characteristic];

            [self goToSecondView:nil];

        }

    }

}

- (void)peripheral:(CBPeripheral *)peripheral didWriteValueForCharacteristic:(CBCharacteristic *)characteristic error:(NSError *)error

{

    if (error) {

        NSLog(@"Error writing characteristic value: %@",

              [error localizedDescription]);

    }

}

// =========================================

// TableView delegates

// =========================================

#pragma mark UITableView Delegate

// reload the table view when a new peripheral device is found and write their name list.

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath

{

    static NSString *cellIdentifier = @"Cell";

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier];

    if (cell == nil) {

        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:cellIdentifier];

    }

    cell.backgroundColor = [UIColor clearColor];

    cell.selectionStyle = UITableViewCellSelectionStyleDefault;

    CBPeripheral* currentPer = [cbArray objectAtIndex:indexPath.row];

    cell.textLabel.text = (currentPer.name ? currentPer.name : @"Not available");

    return cell;

}

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath

{

    [tableView deselectRowAtIndexPath:indexPath animated:YES];

    _mainLabel.text = @"Trying to connect...";

    CBPeripheral* currentPer = [cbArray objectAtIndex:indexPath.row];

    if ( self.peripheral != nil )

    {

        [self.centralManager cancelPeripheralConnection:self.peripheral];

    }

    currentPer.delegate = self;

    self.peripheral = currentPer;

    [self.centralManager connectPeripheral:currentPer options:nil];

    [self.centralManager stopScan];

}

- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section {

    return [NSString stringWithFormat:@"Total count %lu",(unsigned long)cbArray.count];

}

- (CGFloat)tableView:(UITableView *)tableView heightForHeaderInSection:(NSInteger)section

{

    return 40;

}

#pragma mark UITableView Datasource

- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath

{

    return 50;

}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)sectionIndex

{

    return cbArray.count;

}

@end

// =========================================

// SecondViewController

// =========================================

@interface SecondViewController ()

{

}

@property (strong, nonatomic) IBOutlet UILabel *secondLabel;

@end

@implementation SecondViewController

- (void)viewDidLoad {

    [super viewDidLoad];

}

- (void)viewDidAppear:(BOOL)animated {

    [super viewDidAppear: true];

    _secondLabel.text = @"";

}

- (void)didReceiveMemoryWarning {

    [super didReceiveMemoryWarning];

}

- (IBAction)pressButtons:(UIButton *)sender {

    _secondLabel.text = @"";

    NSString *buttonTag = [NSString stringWithFormat:@"%d", (int)sender.tag];

    NSString *data = @"";

    switch (sender.tag) {

        case 1:

            _secondLabel.text = @"Turn left";

            data = @"left";

            break;

        case 2:

            _secondLabel.text = @"Go forward";

            data = @"forward";

            break;

        case 3:

            _secondLabel.text = @"Turn right";

            data = @"right";

            break;

        case 4:

            _secondLabel.text = @"Turn left backword";

            data = @"leftback";

            break;

        case 5:

            _secondLabel.text = @"Move backward";

            data = @"backward";

            break;

        case 6:

            _secondLabel.text = @"Turn right backword";

            data = @"rightback";

            break;

        case 0:

            _secondLabel.text = @"Stop";

            data = @"release";

            break;

        case 11:

            _secondLabel.text = @"Slow speed";

            data = @"speed1";

            break;

        case 12:

            _secondLabel.text = @"Normal speed";

            data = @"speed2";

            break;

        case 13:

            _secondLabel.text = @"fast speed";

            data = @"speed3";

            break;

        default:

            break;

    }

    NSLog(_secondLabel.text);

    if ( self.currentcharacteristic != nil )

    {

        NSLog(@"Write value to peripheral");

        NSData *encodingdata = [data dataUsingEncoding:NSUTF8StringEncoding];

        [self.peripheral writeValue:encodingdata forCharacteristic:self.currentcharacteristic type:CBCharacteristicWriteWithoutResponse];

    }

}

@end