AbstractAmbient temperature and humidity areimportant factors that affect the efficiency and effectiveness of daily lifeactivities. This study was conducted to examine the behaviours, productivity andcomfort of the students in our experimental group at the specified temperatureintervals.A microcontroller-based embedded system wasused for this purpose and this system is designed to monitor the temperatureand humidity values of the environment.
The special Arduino microcontroller weuse is enriched with sensors such as DHT11 and ESP8266, and has been turnedinto a suitable working mechanism for our goal.After the technical installation andsoftware operations have been completed and the device has become operational,the determined area and the experiment group have been tested and the resultshave been recorded.ÖzetOrtam s?cakl??? ve nemi, günlük ya?amaktivitelerinin verimlili?ini ve etkinli?ini etkileyen önemli faktörlerdir.
Buçal??ma deney grubumuzda belirtilen s?cakl?k aral?klar?nda ö?rencilerindavran??lar?n?, verimliliklerini ve konforlar?n? incelemek amac?yla yürütüldü.Bu amaçla bir mikro denetleyici tabanl?gömülü sistem kullan?ld? ve bu sistem ortam?n s?cakl?k ve nem de?erleriniizlemek için tasarland?. Kulland???m?z özel Arduino mikroi?lemcisi, DHT11 veESP8266 gibi sensörlerle zenginle?tirildi ve hedefimiz için uygun bir çal??mamekanizmas?na dönü?türüldü.Teknik kurulum ve yaz?l?m i?lemleritamamland?ktan ve cihaz devreye girdikten sonra belirlenen alan ve deneygrubunda gerekli testler yap?lm?? ve sonuçlar kaydedildi.AcknowledgementsFirst and foremost, we have to thank ourproject supervisor, Mr.
Gökhan Kirkil. Without his assistance and dedicatedinvolvement in every step throughout the project, this paper would have neverbeen accomplished. Also, special thanks to Mr. Orçun Kepez for his help andmany precious ideas about our discussion. We feel very lucky to had theopportunity to work with him. We also take this chance to express gratitude toall of the Kadir Has University Engineering and Natural Science Faculty membersfor their help and support in all four years.
2) BasicConcepts First of all, we want to mention some basicconcepts. Heat is a form of energy measurable in terms of temperature bythermometers. In a natural environment, human body can experience extreme heatswhich is in a range of arctic cold to tropical heat.
And the temperature of theenvironment influences the body temperature.Indoor temperature is one of thefundamental characteristics of the indoor environment. It can be controlledwith the building and its HVAC system. HVAC is the system of heating,ventilating and air conditioning.
According to researchers, the best indoortemperature for daily living is 293 K, 20 ° C or 68 ° F. We call it the bestcondition because the indoor temperature affects several human responses suchas thermal comfort, perceived air quality and performance at work. In thisstudy, we focused on the effects of temperature on performance at our school. Latest researches shows that extreme indoorenvironmental conditions can affect health and productivity in a negative way.So engineers are interested in improving indoor environments and their effectsto increase efficiency. We collect the existing information and tried to getnew test information on how temperature affects productivity and efficiency.Because when we know more about these effects, they could be included intocost-benefit calculations for the building design and operation.
2.1 Previous Studies Temperature’s effect on productivity is animportant topic for researchers. There are lots of example studies about it. Inthis paper, we will talk about G, NECA and T’s original researchdata about temperature and productivity relationship.
‘Grimm and Wagner (1974) and The NationalElectrical Contractors Association (NECA 1969, NECA 2004) conducted experiments to measureproductivity under different weather conditions. Thomas and Yiakoumis (1987)developed a regression model using temperature and humidity to predict PR.'(Ibbs & Sun Analysis of the MCAA Factor Model for Measuring Loss ofProductivity.) *The Productivity Ratio (PR) represents theratio of actual productivity divided by “optimal” productivity.2.2 Embedded system In this thesis, our microcontroller-basedembedded system is designed to monitor the temperature and humidity values ofthe environment.
In addition to monitoring temperature and humidity, we cancontrol the heat index too. Heat index is a combination of air temperature andrelative humidity. It also called ‘humiture’. 2.2.1 Heath Index Heat index is what the temperature feelslike to the human body when relative humidity is combined with the airtemperature.
This has important considerations for the human body’s comfort. Here is the equation of heath index when trepresenting the current air temperature and r representing the currentrelative humidity 2.2.2 Microcontroller Unit (MCU) We designed the system using Arduino Nanomicrocontroller. A Microcontroller (MCU) is basically a simple computer. Thedifference desktops and microcontrollers is that a desktop can run any numberof programs and has software support for different hardware components.
Microcontrollers generally only run one program. In general, this program isspecifically written to control known hardware components. Arduino webserver monitoring system wasprogrammed using the C programming language. The sensor data is read andprocessed by Arduino and it is displayed to the user through the Gobetwinointerface.
3) SystemDesign Parts******We create the embedded system in two parts. System design was the theoretical part.This part describes, explaining the use of the Arduino microcontroller and howit is utilized in the embedded systems in practical part. We create the designand architecture model in this phase. Practical part describes the temperatureand humidity monitoring system. This part of the project is divided into twoparts: Hardware and Software. Practical part includes the wiring diagram andthe source code and it was the phase we did implementation and testing.
4) Components o ArduinoNanoo DHT11Temperature and Humidity Sensoro Breadboardo Powersupplyo Connectingwires We get the measurements of the class viaArduino Nano heat and humidity calculation device which we build and encode. Weuse Arduino Nano, DHT11 humidity and temperature sensor to build a smallcircuit for measurements and ESP8266 Wi-Fi module and Gobetwino for getting thedata and save them in a txt format. Some details about the components which weuse; 4.1) ARDUINO Technically, Arduino is a programmablelogic controller. Officially, it’s an open-source electronics prototypingplatform. Basically, Arduino boards are able to read inputs (ex. message, heath or light) and turn it into anoutput (ex. turning on led, activating a motor, display it in the screen).
Youcan tell your board what to do by sending a set of instructions to themicrocontroller on the board. For example, you can obtain some test resultsusing customized Arduino components for humidity and temperature measurements,as we did in this experiment In this study we use Arduino Nano which isa common type of Arduino to use. The major difference between the standardArduino Uno and Arduino Nano is the number of Analog Pins and the USB Port Wewill discuss these components later in detail.Advantages of Arduino Inexpensive – Arduino boards are relatively inexpensive compared toother microcontroller platforms. Cross-platform – The Arduino Software runs on many operating systems.
Itis not limited to Windows. Simple, clear programming environment – The Arduino has an easy-to-usesoftware and it is flexible to develop. Open source and extensible software – The Arduino software is an opensource tool so programmers can add extensions. Open source and extensible hardware – Circuit designers can extend andimprove it to make their own version of the module. 4.1.
2) Arduino IDE The Arduino Software is a user friendlyprogramming environment: It allows the programmer to create different programsand load them to Arduino microcontroller. The software also called Arduino IDE(Integrated Development Environment). 4.2) DHT11 InDHTXX series there are two types of humidity sensors, DHT11 and DHT22.
Boththese sensors are Relative Humidity (RH) Sensor. According to the Australian Bureau ofMeteorology; Relative humidity (RH)The ratio of the actual amount of watervapour in the air to the amount it could hold.Absolute humidity (AH)The mass of water vapour in a unit volumeof air. As aresult, we can measure both the humidity and temperature. In our project, we used DHT11 is a Humidityand Temperature Sensor, which generates calibrated digital output. It can beinterface with Arduino and it can get instantaneous results. DHT11 provideshigh reliability and long term stability.The DHT11 Humidity and Temperature Sensorconsists of 3 main components.
A resistive type humidity sensor, an NTC(negative temperature coefficient) thermistor (to measure the temperature) andan 8-bit microcontroller. This microcontroller gets analog signals from thesensors and converts them to a single digital signal to send out. You can see the main specifications anddifferences between these two sensors in table 111. The more expensive option,DHT22 has some better specifications.
DHT22 has a wider temperature range. WhenDHT11 can measure the temperature in 0 to 50 degrees, DHT22 can measure it in-40 to 125 degrees. Also with +- 0.5 degree accuracy, DHT22 has more reliableresults than DHT11.
About humidity, DHT22 has better humidity measuring range,from 0 to 100% with 2-5% accuracy, while the DHT11 humidity range is from 20 to80% with 5% accuracy. There are some specifications which DHT11 isbetter than DHT22. They are sampling rate and body size. Sampling rate forDHT11 is 1Hz or one reading every second, while the DHT22 sampling rate is0,5Hz or one reading every two seconds and also the DHT11 has smaller bodysize. These two sensors has the same operatingvoltages (from 3 to 5 volts) and same max currents (2.5mA) used when measuring. 4.3) GOBETWINO Gobetwino is kind of a “generic proxy” forArduino.
It’s a program which is running on your computer and act on behalf of Arduinoand do some of the things that Arduino can’t do on its own.We use Gobetwino program for display thedata we get from the humidity and temperature measurements with Arduino. And wesave them as a text file on Gobetwino. 5) ExperimentalStudies Before beginning to monitoring the class,certain requirements were set. The system is needed to be easy to use and theuser could remotely monitor environmental changes inside the class. Sensor datarequired to be collected and stored for showing changes in the environmentvariables. We had a fixed temperature to get reliable results.
The measurements accomplished by the datacommunications between Arduino, DHT11 Sensor Module, ESP8266 WIFI module andGobetwino. Arduino’s Celsius scale thermometer and percentage scale humiditymeter displays the ambient temperature and humidity through Gobetwino displayand also record it as a text file. We take the measurements on 30.
11.2017 and07.12.2017, 2 weeks consecutively, in smart class of Kadir Has University. Wetake two measurement tests by Arduino each day.
One is before the class whenthe lecture didn’t start and one is after the lecture, while the students writetheir reflection papers about the lecture and filling our survey questions. We try to figure out their comfort level inthe temperature we fixed by HVAC system and their motivation in thisenvironment. First week we fixed the classroom temperature at 20.00 C ° and thesecond week we fixed it at 27.00 C °. There were 26 people in the test groupand we neglected the genders and clothes while we commentate the results. For this experiment, we divided the classinto eleven regions.
We gave a number to each region and recorded the resultsof each region separately. We ensured students sit in the same places in thetwo days of experiment. At the end of the class we asked the students to writea reflection paper about the lecture and to answer the survey questions whichwe gave them before the class. We asked them for mark where they sit in classon the graph we gave them and mark the spot they want to sit if it is possible. A systematic approach has been followed inmeasurement with the microcontroller based system. The results obtained from the measurementhave shown that the system performance is reliable and accurate. This projecthas been completed successfully.
We get our data with Arduino and transmit themwirelessly to a processing sketch, where they are visualized for simpleanalysis. So our goal of integrating all of the underlying technologies hasbeen met.