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Weather SenseBox: An Arduino Based Approach to
Integrate the Work on Sensor Platforms in High School
Classes
Bachelor's Thesis
Submitted to the
University of Münster
Institute for Geoinformatics
Submitted by: Jan Alexander Wirwahn
Supervisors: Dr. Arne Bröring & Thomas Bartoschek
Münster, October 2012
I
Table of Contents
Nomenclature III
List of Figures V
List of Tables VII
Abstract 1
1. Introduction 1
1.1 Motivation 1
1.2 Structure 2
2. Background 3
2.1 Open-Source Hardware 3
2.2 Climatic Observations 4
2.3 Educational Standards 4
2.4 Citizen Science 6
2.5 Related Work 7
3. Requirement Analysis 7
3.1 School Requirements 7
3.2 Climatic Measurements and Values 8
3.3 Requirements and Categorization 9
4. Realization of the Weather SenseBox for Schools 10
4.1 System Components 10
4.1.1 Arduino 10
4.1.2 Sensors 12
4.1.3 Prototype Architecture 20
4.2 Integration into Classes 23
5. Evaluation 26
5.1 Data Evaluation 26
5.2 Practical Workshop 30
6. Conclusion 34
6.1 Discussion 34
6.2 Outlook 35
References 35
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II
A. Appendix i
A.1. Software i
A.2. Data CD ....................................................................................................... i
Affirmation ii
......................................................................................................
III
Nomenclature
°C Degrees Celsius
AWS Automated Weather Station
CSV Comma Separated Value
DIY Do it Yourself
DWD Deutscher Wetterdienst (German Meteorological Service)
E²PROM Electrically Erasable Programmable Read-Only Memory
GLOBE Global Learning and Observations to Benefit the Environment
GPS Global Positioning System
hPa Hectopascal
I²C Inter-Integrated Circuit
IDE Integrated Development Environment
ifgi Institute for Geoinformatics
ILÖK Institute for Landscape Ecology
IP Internet Protocol
LAN Local Area Network
LED Light-Emitting Diode
m/sec Meter per Second
MC Microcontroller
MHz Megahertz
mm Millimeter
ms Millisecond
OSHW Open-Source Hardware
OSS Open-Source Software
PC Personal Computer
Pa Pascal
RH Relative Humidity
RTC Real Time Clock
IV
SCL Serial Clock
SDA Serial Data
SDSS The Sloan Digital Sky Survey
sec Second
SPI Serial Peripheral Interface
UP Uncompensated Pressure
UT Uncompensated Temperature
V Volts
WMO World Meteorological Organization
V
List of Figures
4.1.1 Figure 1: The Arduino Mega 2560 R3 microcontroller board [26].
4.1.1 Figure 2: The Arduino Ethernet Shield [29].
4.1.2 Figure 3: Transmission start sequence for SHT15 [33].
4.1.2 Figure 4: Measurement sequence of the BMP085 [37].
4.1.2 Figure 5: Bouncing problem at a digital input. MC will read nine state changes
instead of one.
4.1.2 Figure 6: Connection of the rain gauge to the Arduino Mega.
4.1.2 Figure 7: Connection from anemometer to Arduino Mega.
4.1.2 Figure 8: Wiring between wind vane and Arduino Mega
4.1.3 Figure 9: The waterproof box including the core of the station.
4.1.3 Figure 10: Schematic wiring of all components.
4.1.3 Figure 11: Sample from log.csv. Values are: date, time, seconds since start,
temperature (°C), humidity (%), pressure (pa), rain gauge counter,
anemometer counter.
4.1.3 Figure 12: Sample from windlog.csv. Values are: date, time, seconds since start,
wind direction.
5.1 Figure 13: The prototype of the weather station was setup on the ILÖK in around
2,5m height.
5.1 Figure 14: Temperature readings of SHT15 and ILÖK station.
5.1 Figure 15: Humidity measurement of the SHT15 compared to ILÖK station values.
5.1 Figure 16: Pressure readings of the BMP085 and the ILÖK station.
5.1 Figure 17: Nearly no rain fall was measured by the prototype and the ILÖK station.
5.1 Figure 18: Wind speed measurements of the prototype and the ILÖK station.
5.1 Figure 19: Wind Direction measurements of the prototype and the ILÖK station.
5.2 Figure 20: The pupils were introduced to the Arduino Uno microcontroller.
5.2 Figure 21: The Parrot AR.Drone multicopter with the Arduino board, thermometer,
GPS and radio data transmitter.
VI
5.2 Figure 22: In total we had more male than female participants (a). 66% of the pupils
were under the age of 15.
5.2 Figure 23: The mix of tinkering and programming was well chosen for the workshop
(a) and nearly all the pupils found the content very interesting (b).
5.2 Figure 24: All of the pupils would like to have the weather station integrated into class
(a). Also all of them are interested in additional work than just building the
station (b).
5.2 Figure 25: The motivation to work with the Arduino boards after the course was very
high.
VII
List of Tables
3.3 Table 1: Overview and prioritization of the requirements.
4.1.2 Table 2: Properties of the humidity sensor of the SHT15.
4.1.2 Table 3: Properties of the temperature sensor of the SHT15.
4.1.2 Table 4: Cable connections between SHT15 Breakout and Arduino Mega.
4.1.2 Table 5: Main properties of the BMP085.
4.1.2 Table 6: Wiring between BMP085 and Arduino Mega.
4.1.2 Table 7: Measurement mode of the BMP085 and resulting effects.
4.1.2 Table 8: Analog voltage output with corresponding directions [40].
4.1.2 Table 9: Pin connections of the RTC and the Arduino Mega.
4.2 Table 10: Material costs of the weather station prototype.
4.3 Table 11: Topics for climatology school lesson in Physics. Modified from [19].
4.3 Table 12: Topics for a Arduino based series of Computer Science lessons.
4.3 Table 13: Climatology teaching series in Geography class.
1
Abstract
Arduino provides an open source hardware prototyping platform, which allows an easy
implementation of sensors and interactive elements. The goal is to make sensor prototyping
available for children at early ages. This thesis provides an Arduino based approach of a
weather station prototype, designed for the integration in school lessons or as project work.
To make this possible, technical requirements according to the prototype and educational
requirements for a successful integration in school lessons, have to be considered in equal
measure.
1. Introduction
This chapter describes the idea and motivation behind the project. In the following sections,
the goals for the thesis are defined as well as its structure is explained.
1.1 Motivation
Children shall be prepared for an independent life in the modern world of today. Already 75%
of the teenagers in Germany posses an own PC and even over 90% a mobile phone [1].
Therefore, it is absolutely necessary to teach them computer science and technology, already
at early ages. It is very important to assure that children not only know how to use computers,
smart phones or other technical products but also understand how such systems work. The
idea is to prepare the children to work on and with modern technologies in the future. This
should be promoted by the schools as early as possible. Therefore, integrating the work on
sensor platforms in school lessons is a chance for schools to deal with the technical
development. Letting children build up a product like a weather station, is giving them a sight
into the workflow of constructing and programming a complex system.
The main goal of this thesis is the deployment and documentation of a weather station
prototype, partly based on the SenseBox that was developed during a study project at the
Institute for Geoinformatics (ifgi) in Muenster [2]. The SenseBox is a small, lightweight and
low cost sensor platform, operating as a web server. It is a solution for a flexible usage of
sensor data, which is typically transformed into observations.
2
One advantage of the SenseBox approach is that the main parts of a data infrastructure, such
as configured servers for data storage and the SenseBox portal for visualization of the boxes,
already exist. With this portal and its connections between different boxes, it is also possible
to compare related datasets. This enables advanced processing, e.g. regional instead of local
climatic models or even bringing up correlations between different sensor platforms in the
portal. Further server-side development is necessary to make all spatial data available via the
internet. The enhancement of databases and data structure will be future work and are not
covered by this thesis.
The SenseBox weather station is developed in collaboration with the GI@School initiative
also located at the ifgi [3]. The thesis will describe the use case for a low level approach of
sensor platforms which could be used by high school teachers. The teachers are intended to
build up the hardware setup and to implement the microcontroller's firmware together with
pupils to improve their technical knowledge. This should be a possibility for pupils to get in
touch with a practical approach on technical work. Further statistical evaluation with resulting
data from a self-constructed weather station should be more motivating for pupils than just
working with abstract data samples. Therefore, a goal is to prepackage a complete DIY-Kit
with hardware, software and a construction manual designed for pupils in high school.
The outcome of the thesis could be used as part of a high school’s subject and has the ability
to be well accepted by pupils. An evaluation of a survey in context of the GI@School
activities is going to proof this.
1.2 Structure
An overview about ideas and goals was already given in Section 1.1. In the following,
Chapter 2 provides background knowledge and discusses topics related to the thesis.
Requirements for the prototype and for schools are explained in Chapter 3. Chapter 4 focuses
on the construction of the prototype with regard to the purposes already mentioned in the
motivation. Moreover, all used sensors are explained in detail as well as the integration into
school class. Chapter 5 describes an evaluation of the prototype, compared to a professional
weather station. Additionally, it shows first experiences in constructing the station together
with pupils from different ages. The final chapter, Chapter 6, includes a discussion about the
whole project and identifies aspects for future work.
3
2. Background
This chapter discusses fundamentals for the development of the prototypical weather station.
It provides general information about climatic measurements and educational standards in
Germany. For further understanding of the topic Citizen Science and related word are also
introduced.
2.1 Open-Source Hardware
Open-Source has become a popular expression, but mostly with regard to software. The
principles and definitions of Open-Source Hardware (OSHW) are closely related to those of
Open-Source Software (OSS) from the Open Source Initiative [4, 5]. Interested people can
study, modify, distribute, make and sell designs based on those of OSHW products [6].
Through open development, people get the possibility to learn and understand how OSHW
works, so that they are able to control and modify their technology. Machines, devices, or
other physical things produced under the OSHW license must comply to the definitions of the
Open Source Hardware Association [4].
Arduino Platform
Arduino is a prototyping platform containing a microcontroller board (MC) as core element, a
programming language and an integrated development environment (IDE) [7]. OSHW MCs
from Arduino are based on ATmega8, ATmega168 and latest boards on ATmega2560. They
can be used to develop interactive prototypes, which are using input from sensors to control
output devices connected to the same board. The capabilities of the MCs allow several
methods for in- and outputs of signals.
The simplified IDE with a wire-based programming language also allows beginners to realize
complex projects in short time. Documentation of the IDE and the language reference can be
found on the Arduino homepage [8]. All code samples are released into the public domain.
Additionally, the language can be extended with C++ libraries to enable more functionality.
All official software tools from Arduino are published under the OSS license and are
platform-independent.
The well documented Arduino hard- and software makes it even possible to rebuild MCs by
oneself [9]. However, pre-assembled Arduino boards are relatively inexpensive compared to
other commercial MC platforms available on the market.
4
2.2 Climatic Observations
The World Meteorological Organization (WMO) developed several standards for climatic
observations [10]. The most important aspects are selection of sites, installation and
calibration of the station and data interpretation [11]. They are meant as basis for an
international exchange of climatic data and weather observations. National weather services
like the DWD in Germany have to build up their weather stations according to those
guidelines to keep their data (inter-)national comparable. However, the WMO standards are
more guidelines than rules because some environments make it impossible to stick to them
[12]. Especially for surface observations in urban areas, standards cannot completely be met
because climatic variables are varying over very short distances in populated areas [13]. The
purpose of an observation has to be considered when finding appropriate solutions for
measuring climatic values in a city [10].
Automated Weather Stations
Automated weather stations (AWSs) are meteorological stations, which perform climatic
observations and data transmission automatically [14]. Main advantages compared to human
weather observations are, that measurements, read out by a central data-acquisition unit, are
more reliable and can be performed much more frequently. Sensors of an AWS are operated
by a microprocessor. It allows exact sampling of sensor data and processing for averaging or
filtering of the samples (according to the WMO standards in [11]). The result will be a series
of observations which are representative over a limited area.
2.3 Educational Standards
In 1997 the Conference of the Ministers of Education and Cultural Affairs in Germany
(Kultusministerkonferenz) decided to establish educational standards in which competences
that pupils have to achieve until a certain grade for the different school subjects are specified
[15]. Hereafter, an overview of the areas of competences included in the educational standards
for intermediate school certificate is given for the subjects Geography, Computer Science and
Physics.
Geography
There are six areas of competence for Geography that need to be acquired by pupils with
intermediate school certificate [16]:
5
Knowledge specific to the subject
Spatial orientation
Gathering information/methods
Communication
Evaluation
Action
Particularly, the project of this thesis aims at the areas of specific knowledge and gathering
information. Working with the weather station will help pupils to understand the weather as a
continuous process in the atmosphere. Building up the weather station will deepen their
knowledge about gathering climatic values. Naming physical variables as factors in the
system of a weather cycle is only one example for that. Field observations can then be used to
process information in order to answer geo-scientific questions about climate processes [16].
Computer Science
Educational standards for Computer Science are divided into content- and process-
competences like the following [17]:
Content Process
Information and data
Algorithms
Languages and automats
Computer systems
Informatics, people and society
Modeling and implementing
Establish and evaluate
Structuring and networking
Communicate and cooperate
Representing and interpreting
The work with the Arduino platform allows enhancement of abilities on both categories.
Obviously, algorithms for processing observations, derived from sensor samples, are
containing the work with different data types and operators. This as well as methods of
hardware communication, which are part of the project, will also exercise the content
competences. Moreover, pupils have to collaborate to construct and program the station.
Furthermore, evaluating and analyzing the station's data is suitable to exercise process
competences.
Physics
Four areas of competences are defined as required basic knowledge for Physics in
intermediate school [18]:
Knowledge specific to the subject
Gathering information/ methods
Communication
6
Evaluation
The fundamentals of meteorology and physic of the atmosphere should be discussed in
Physics school lessons. As this is not part of the original lesson plans, it can be done as
alternative to thermodynamics. It helps to see and understand natural phenomena according to
the first area of competence. A concept for integrating meteorology in Physics class can be
found in [19]. It includes temperature analysis, dynamics in air pressure, types of humidity
and reactions in the atmosphere.
2.4 Citizen Science
Volunteers are part of Citizen Science if they collect or process data under a scientific issue
[20]. As different participants have different knowledge about this issue or methods, they will
not have the same engagement in the project they are taking part in. Thereby, the degree of
participation has different levels [21].
The Weather SenseBox project enables pupils to build up their own sensor platform. With
their station, they can contribute their measurements to a scientific database. Citizen Science
projects can be the platforms for involving the pupils into science.
The following two examples show how science can be driven forward through open voluntary
assistance.
Galaxy Zoo
One example for a Citizen Science initiative is the Galaxy Zoo project which started in 2007
[22]. The Sloan Digital Sky Survey (SDSS) searched for a way to analyze high resolution sky
images taken at Apache Point Observatory in New Mexico during their large scale
astronomical observations [23]. Interested volunteers were called to classify galaxies on sky
images from the SDSS. The idea behind it is that the appearance or rotation direction of a
galaxy can tell a lot about its structure.
Globe Project
The Global Learning and Observations to Benefit the Environment (GLOBE) started in 1995
as a worldwide science and education program for primary and secondary schools [24].
Strengthen ecological awareness and science-oriented education are the main goals of
7
GLOBE. Today it is a network of students, teachers and scientists with contributions from
over 24.000 schools from over 100 countries.
2.5 Related Work
Projects like the LEGO Mindstorms show that there is space for integrating ambitious ideas
into school lessons, which are explaining modern technologies like robotics or, in our case,
the work on a sensor platform.
LEGO Mindstorms Education
The LEGO Mindstorms Education is a commercial program to bring robotics to upper-
primary school classes [25]. Already children in the age of eight years and above can build
robots and use the LEGO software to program instructions for a robot. Some of the robots
provide data logging functions gathering and analyzing data.
3. Requirement Analysis
The Weather SenseBox itself is meant to be a technical project work for pupils at intermediate
grade in high schools. The requirements are split into two categories: technical and
educational. The technical category includes functional requirements the prototype has to
accomplish and the educational category contains requirements for enabling a successful
integration into school class.
3.1 Technical Requirements
Obviously, the main task of the weather station is to measure climatic variables. In doing so,
averaged values have to be stored on the device. These values are used to provide
observations of the current state of the weather. Sampling procedure and logging functions
have to be coordinated by the MC and have to be as accurate as possible. Understanding about
the sensors is crucial to achieve representative observations.
Requirement 1: Representative observation have to be stated by the station.
The prototypical Weather SenseBox is the basis for future projects. It should not be a single,
but a long term project which can be extended in future. Because of that, it should be
8
adaptable to further sensor setups (e.g. for air quality measurement) so that an investment in
the new system is more profitable for the schools.
Requirement 2: Reserve resources for further sensor upgrades.
Receiving observations from the sensor readings in highest precision is not an aim of the
Weather SenseBox. Nevertheless, it is important to measure accurate enough to display the
current weather. Therefore, the hardware setup and the implemented software has to be tested
and evaluated to ensure correctness of the displayed observations.
Requirement 3: Sensor calibration and hardware setup has to be tested and evaluated.
3.2 Educational Requirements for Integration into Schools
The station will be placed at a selected location on the school campus. As already mentioned
in Section 2.2, the environment has influence on the representativeness of the measurements
as well as sensor calibration and sampling methods. Therefore, it is necessary to work out
detailed instructions for a correct exposure of the station and to follow the guidelines from
WMO [11] in terms of data gathering. This could also be done by pupils in school class.
Requirement 4: Finding an appropriate location for the station must be included in the
concept.
Some knowledge in the principles of electrical engineering and object orientated
programming is required to understand the functionality of the station. This means that pupils
have to learn about Arduino MCs and their programming. The modules of the station have to
be introduced and tested in class by the pupils before constructing the station. Therefore, a
detailed documentation of the station should be provided with the station.
Requirement 5: Detailed documentation of the weather station and its single
components have to be worked out to allow an easy access into the
work with Arduino MCs.
Teachers cannot implement the weather station into their classes if it cannot be adopted to the
educational standards. In consequence, this thesis must not just focus on the development of a
prototype. An approach for a structured work with the topics coming up with the station in the
school subjects, which have been mentioned in Section 2.3, have to be pointed out during the
different steps of development.
Requirement 6: The work on and with the weather station must follow the educational
standards.
9
An important point for the schools will be the financial feasibility of such a project. For a
successful integration of the Weather SenseBox, it has to be affordable for the schools. This
means that choosing equipment for the station has to be considered carefully. An appropriate
balance has to be found between functionality and affordability.
Requirement 7: The project has to be as low-cost as possible.
Besides the technical evaluation, the work with the prototype should be tried out together with
pupils as well. This has to be done directly with the pupils at school or in a school lesson-like
environment. During these lessons, the station has to be constructed and put in practice by the
pupils themselves.
Requirement 8: Evaluate the work with the weather station directly together with
pupils from different ages.
3.3 Overview
An overview of all requirements is given in Table 1. The most important thing on the
technical side is that the station delivers reliable measurements, which means the sensors have
to be calibrated and tested properly. On the educational side, the low-cost ability is crucial for
schools. Moreover, it is the good documentation to facilitate a start with the weather station
construction kit.
Nr. Category Description
1 Tech. Representative Observations
2 Tech. Upgradeable
3 Tech. Sensor calibration/evaluation
4 Edu. Location finding
5 Edu. Low Cost
6 Edu. Documentation of all Parts of the Station
7 Edu. Educational Standards
8 Edu. Pupil Evaluation
Table 1: Overview of technical and educational requirements.
10
4. Realization of the Weather SenseBox for Schools
In this chapter, the features and the functionality of the prototype are explained in detail. In
order to set up the weather station, several tasks had to be handled. The first task was to select
the different components like MC and sensors for the prototype. In the second step, the
sensors had to be integrated in a circuit together with the microcontroller. The final step was
to create a concept to integrate the weather station into school class. Chapter 4 is divided
according to these steps.
4.1 Hardware Components
The microcontroller controls the sensor's data sampling and storage. Sampling rates of
temperature and pressure sensors are depending on their time constant and resolution of the
measurement. In the following, functionality and properties of the MC and each of the sensors
are explained in detail.
4.1.1 Arduino
The Arduino components can be seen as the core of the station as they provide main
functionality from sensor communication up to data logging. The Arduino Mega and the
Arduino Ethernet Shield are introduced in this section.
Arduino Mega 2560 R3
Figure 1 shows the Arduino Mega, which is the microcontroller board of the weather station.
Sensors can be attached to a digital input / output pin or to an analog input pin.
Figure 1: The Arduino Mega 2560 R3 microcontroller board [26].
11
Main advantage compared to other Arduino boards is the 16MHz operating frequency and a
flash memory of 256 Kbytes of the ATmega2560 MC chip [26]. This solves the memory
problem that appeared when using the Arduino Uno board at the beginning of the project.
If not connected to USB, the board needs an input voltage between 7 and 12V. This can either
be done with an AC-to-DC adapter connected to the power jack or with batteries connected to
Vin and GND pins on the board. The 5V and 3.3V pins are regulated voltage outputs for
power supply of external devices like sensors.
In total, there are 54 digital pins on the Arduino Mega. They can be used as input or output
and are operating at 5V. To read out the input of a sensor at a digital pin, the function
pinMode(pin, INPUT) has to be called. After that, its state can be checked by calling
digitalRead(pin). It returns either HIGH or LOW.
Some of the digital pins have special functions as indicated by their labels printed on the
board. For the weather station communication, pins 20 and 21 are used as two of the sensors
require a serial two-wire interface (also referred inter-integrated circuit or I²C) for
communication. Data line (SDA) and clock line (SCL) have to be connected to the
corresponding connection of the sensor.
It is possible to connect more than one device to the I²C bus as each device has its own
address. To enable read() and write() functions for sensor communication the Wire
library of Arduino has to be used [27].
Pins 50 to 53 are used for the serial peripheral interface (SPI). Most of Arduino compatible
shields are using SPI communication and the SPI library [28]. For using functionalities of a
certain shield, additional libraries have to be used.
Moreover, one of the 16 analog inputs is used. The function analogRead(pin) reads out the
incoming voltage and returns a value in 10 bit resolution.
Arduino Ethernet Shield
The Ethernet Shield from Arduino combines a W5100 ethernet controller with a micro SD
card logger [29]. It is especially made for Arduino boards and connected over the SPI port.
No further circuit is needed to connect the boards as it has to be mounted just on top of the
Arduino Mega. A top view of the shield is shown in Figure 2.
12
Figure 2: The Arduino Ethernet Shield [29].
It has to be considered that pins 50, 51 and 52 on the Arduino Mega cannot be used as digital
in- or output any more when using the Ethernet Shield as they are being used by the SPI bus.
Pins 4 and 10, which are used for the W5100 and for the SD card cannot be used as well. All
other pins on the shield can be connected in the same way as mentioned in the description of
the Arduino Mega.
At the current state of the project, the Ethernet Shield is mainly used for data logging. Even
though the latest observation is accessible over LAN (IP address is 192.168.0.80) it is not yet
completely integrated into the web.
During the testing, it turned out that there is a problem with using the W5100 and the SD card
at the same time. This problem is caused because both components are sharing the same SPI
bus [29]. However, it is planned to establish an external server for data storage. The Arduino
will be configured to act as a http client and the SD card capabilities are then deactivated.
This should fix the communication problem.
To integrate functionalities of the Ethernet Shield into the whole system, Ethernet [30] and
SD [31] libraries are used.
4.1.2 Sensors
Characteristics and functionality of each sensor used by the prototype are explained below.
Moreover, connection and communication examples are given in this section.
Relative Humidity and Air Temperature
13
The SHT15 from Sensirion includes a capacitive humidity and a band-gap temperature sensor.
Electric thermometers have to be protected from radiation and need to be shielded [11]. Both
sensors are individually calibrated accurately by the manufacturer and provide digital output
[32].
The SHT15 was chosen because of its high resolution, accuracy and its long term stability.
Tables 2 and 3 give an overview of the main sensor characteristics taken from the datasheet
[33].
Parameter Condition Min. Typ. Max. Unit
Resolution typical 0.4 0.05 0.05 %RH
Accuracy typical
±2.0
%RH
Response Time (63%)
8
sec
Operation Range
0
100 %RH Table 2: Properties of the humidity sensor of the SHT15.
Parameter Condition Min. Typ. Max. Unit
Resolution typical 0.04 0.01 0.01 °C
Accuracy typical
±0.3
°C
Response Time (63%) 5
30 sec
Operation Range typical -40
123.8 °C Table 3: Properties of the temperature sensor of the SHT15.
For a connection to the MC, the DATA pin needs to be pulled up with a resistor to the power
supply pin of the MC. Additionally, VDD and GND must be decoupled with a capacitor [33].
The SHT15 Breakout from SparkFun [34] has implemented these requirements and is used
here to reduce the complexity of the circuit.
SHT15 Breakout Arduino Mega Pin
VDD 3,3V
Data 5
SCK 6
GND GND Table 4: Cable connections between SHT15 Breakout and Arduino Mega.
The SHT15 requires recommended source voltage of 3.3V. For communication between the
MC and the sensors, a two-wire serial interface is used whereas the serial clock input (SCK)
synchronizes traffic of the bidirectional serial data line (SDA or DATA). Connection to the
Arduino Mega is done as shown in Table 4.
As an example for sending measurement commands to the SHT15, a transmission start
sequence (see Figure 3) has to be issued by the MC. The digital pin 5 (connected to DATA)
14
must be set low while SCK is high, followed by a low pulse on SCK. When pin 5 is set high
again after SCK is set high again as well, the sequence is complete.
Figure 3: Transmission start sequence for SHT15 [33].
Three address bits (always '000') and additional five command bits ('00011' for temperature,
'00101' for pressure) have to be send after that to start a measurement.
For communication, the SHT1x library is used [35] so that it is not necessary to implement
these sequences step by step.
Air Pressure
For air pressure readings, the digital pressure sensor BMP085 from Bosch Sensortec is used
[36]. It is based on the piezo-resistive technology and can be integrated into the system over
the I²C interface [37].
The digital pressure sensor has an additional temperature sensor integrated. The internal
temperature measurement is used to correct the sensor reading as it changes with temperature.
The BMP085 was chosen for the prototype because of its good accuracy through individual
precise calibration and its long term stability feature. The main characteristics are summarized
in Table 5.
Parameter Condition Min. Typ. Max. Unit
Resolution typical 0.04 0.01 0.01 hPa
Accuracy typical
±1.0
hPa
Response Time Mode
4.5
25.5 ms
Operation Range
700
1100 hPa Table 5: Main properties of the BMP085.
The I²C interface and a read-only-memory register (E²PROM) are part of the control unit of
the BMP085. In the E²PROM eleven 16bit calibration coefficients are stored and used to
compensate offset of temperature and pressure readings. As temperature is a factor for air
pressure calculation, it has to be known to calculate the true pressure. Reading of the
temperature can be done with the piezo-resistive sensor as well.
15
A measurement sequence with the
complete algorithm is shown in
Figure 4. It has to be implemented to
the MC according to this order.
After the MC has sent a start
sequence, the calibration data is
requested from the E²PROM registers.
The 16 constants need to be read out
only once and are stored on the MC.
Then the MC has to wait for
uncompensated temperature (UT) and
pressure (UP) readings from the
sensors. The stored calibration data is
now used to calculate temperature in
°C and pressure in Pa. After applying
the algorithms, the sensor waits for
the next measurement command.
As additional factor for true pressure
calculation, an oversampling mode
can be chosen to set the internal
sampling of the sensor for one
measurement. Changing the mode to a
higher resolution will increase the
accuracy of a measurement but also
has an impact on energy consumption,
reaction time and the long term
stability [37].
Table 7 gives an overview about the
four oversampling setting modes. As
the weather station is designed for
long and continuous measurements,
standard mode will be sufficient. Figure 4: Measurement sequence of the BMP085 [37].
16
As mentioned before, the BMP085 pressure sensor is using the I²C protocol to communicate
with the microcontroller and has to be connected to SDA and SCL pins on the Arduino Mega
as shown in Table 6.
BMP085 Breakout Arduino Mega Pin
SDA 20
SCL 21
XCLR Not Connected
EOC Not Connected
GND GND
VCC 3,3V Table 6: Wiring between BMP085 and Arduino Mega.
The altitude of the instrument has to be taken into account as well, because air pressure
decreases with increasing height. For getting comparable values it has to be calculated to sea
level pressure [11].
For implementation of the algorithm shown in Figure 4, the bmp085 library is used [38].
Mode
Oversampling
Setting
Internal
Samples
Conversion
Time [ms]
Noise
[hPa]
Ultra Low Power 0 1 4.5 0.06
Standard 1 2 7.5 0.05
High Resolution 2
4 13.5 0.04
Ultra High Resolution 3 8 25.5 0.03 Table 7: Measurement mode of the BMP085 and resulting effects.
Working with the BMP085 should be done carefully, because it could be damaged by shocks
or when getting in contact with water. Therefore, it should be installed in a dry environment
with constant temperature. E.g. the waterproof case which is slightly heated by the
microcontroller itself is a good choice.
Precipitation
Rainfall is measured by a gauge included in the Weather Sensor Assembly available from
SparkFun Electronics [39]. Each time the bucket is emptied, a reed switch closes once. This
corresponds to 0.28mm of rain fall [40]. For each state change of the switch a digital counter
is increased by one.
A problem that frequently appears at trying to capture the state change of a switch is called
bouncing problem. State change means that the input at a digital pin on the Arduino changes
from high to low (equals from 5V to 0V) or vice versa. The problem is that each switching
17
contains interferences in the signal before it reaches the level of 5V or 0V. This can lead to
multiple counts from only one state switch. A visualization of the problem is shown in Figure
5.
Figure 5: Bouncing problem at a digital input. MC will read nine state changes instead of one.
One solution is either to integrate a capacitor to the circuit or to define a software method with
a debounce interval of some milliseconds, which is called every time a state change is
recognized.
The two wires coming from the rain gauge have to be connected to the Arduino Mega as
shown in Figure 6.
Figure 6: Connection of the rain gauge to the Arduino Mega.
The red line must be connected to GND while the green line is pulled-up with a 10kΩ resistor
to 5V. The output of the sensor has to be connected to digital pin 19 on the Arduino Mega.
18
A disadvantage of this method is that only rain fall can be measured. To include snow fall in
the precipitation measurement a self heated device would be needed. Temperatures below 0°
Celsius could also lock up the anemometer. This should be taken into account when analyzing
the data of the rain gauge.
Wind Speed
The wind speed is measured with a cup-type anemometer included in the Weather Sensor
Assembly [39]. In principle, it works exactly like the rain gauge. At every turn, a magnet
passes a switch, which is connected to a digital counter. 0.67 meter per second of wind speed
causes the switch to close once per second [40]. Software debouncing is performed as
described above.
The anemometer is connected with a two wired cable to the wind vane. The two center wires
(yellow and red) of the cable coming from the wind vane are used by the anemometer. Again,
the red cable needs a pull-up resistor before connecting it to 5V. The yellow cable is
connected to GND.
Figure 7: Connection from anemometer to Arduino Mega.
Wind Direction
The wind vane of the Weather Sensor Assembly [39] contains eight switches, each of them
connected to a resistor with different resistance values. A magnet switch can close two
switches at once which allows to indicate 16 different positions. The voltage of the output
cable can be measured at an analog input on the Arduino Mega. Directions for corresponding
voltage output can be found in table 8.
19
Direction
(Compass)
Direction
(Degrees)
Voltage
Output
N 0 / 360 3.84
N-NE 22.5 1.98
NE 45 2.25
E-NE 67.5 0.41
E 90 0.45
E-SE 112.5 0.32
SE 135 0.90
S-SE 157.5 0.62
S 180 1.40
S-SW 202.5 1.19
SW 225 3.08
W-SW 247.5 2.93
W 270 4.62
W-NW 292.5 4.04
NE 315 4.78
N-NW 337.5 3.43 Table 8: Analog voltage output with corresponding directions [40].
The green and black outer wires of the cable from the wind vane have to be connected to the
Arduino Mega as shown in Figure 8.
Figure 8: Wiring between wind vane and Arduino Mega.
As mentioned before, the incoming voltage can be measured with an analog pin on the
Arduino Mega. The values, which are read out at the analog input, have to be converted from
10 bit (0-1023) to a scale between 0 and 5V (0 to 5000). The resulting voltage can then be
used to grab a corresponding value from a list according to Table 8.
20
Testing of the wind vane showed that voltage values slightly differ from the values given in
the table. This could lead to misinterpretation of the signal.
Real Time Clock
The real time clock module (RTC) SEN12671P from Seeed Studio [41] is based on the
DS1307 clock chip and used for returning exact real time. The time has to be set only once on
the device. After that, the RTC provides seconds, minutes, hours, day, month and year
information [42].
The equipped battery and the automatic power fail detect feature make the RTC much more
reliable as the provided method on the Arduino Mega because it is not affected by loss of
energy.
For reading out time information from the RTC's registers, the I²C protocol is used. Like with
the BMP085, the SDA and SCL connections of the RTC have to be connected to pin 20 and
21 on the Arduino Mega. Furthermore, it needs 5V power supply. A summary of correct
wiring is given in Table 9.
Grove - RTC Arduino Mega Pin
SCL 21
SDA 20
VCC 5V
GND GND Table 9: Pin connections of the RTC and the Arduino Mega.
The library RTClib for RTC modules with DS1307 chips from Adafruit [43] is used for the
communication between sensor and MC. The library contains easy methods for setting the
time on the RTC and for reading out calendar and clock information.
The manufacturer stated that one battery can be used for several years. But to avoid loss of
information, it is recommended to check voltage not less than twice a year [43].
4.1.3 Prototype Architecture
The weather station consists of two parts: a waterproof case for the electronics and a small
pole for attaching external sensors. Anemometer and wind vane are mounted on top of it. In
order not to affect wind measurements, rain gauge and shielding for the SHT15 sensor are
installed at the lower end. The core of the station is placed in the waterproof case. It contains
the MC with the Ethernet Shield, the BMP085 and the RTC.
21
Figure 9: The waterproof box including the core of the station.
Cables from the exterior sensors as well as connections for power supply and LAN are
connected to the core in a waterproof case, which is shown in Figure 9.
The self made bread boards are designed to make assembling and upgrading more easy. No
further soldering is needed to setup the station. A schematic overview of the wiring is shown
in Figure 10.
Figure 10: Schematic wiring of all components.
22
12.10.2012,8:0,63600,7.80,66.45,101645,0,1626
12.10.2012,8:10,64200,7.84,65.26,101643,0,1534
12.10.2012,8:20,64800,7.93,63.86,101614,0,1290
12.10.2012,8:30,65400,8.04,62.78,101551,0,1084
12.10.2012,8:40,66000,8.04,61.09,101516,0,1174
12.10.2012,8:50,66600,7.99,57.83,101550,0,1745
12.10.2012,9:0,67200,7.93,49.77,101627,0,1692
12.10.2012,8:0,63600,SO-S
12.10.2012,8:1,63660,SO
12.10.2012,8:2,63720,SO
12.10.2012,8:3,63780,SO
12.10.2012,8:4,63840,SO
12.10.2012,8:5,63900,SO
At the current state of development, the prototype can read temperature, humidity, pressure,
wind speed and direction and rainfall. Samples from the BMP085 (air pressure) and the
SHT15 (air temperature and relative humidity) are stored every 10 seconds.
After 60 readings ( ≙ 10 minutes) the values are summed up and their average is calculated.
After that, a time stamp from the RTC, the averaged results and the values of the rain gauge
and wind speed counters are stored on the SD card of the Ethernet Shield in a comma
separated value file (csv). A sample from the logging file can be found in Figure 11.
Figure 11: Sample from log.csv. Values are: date, time, seconds since start, temperature (°C), humidity
(% RH), pressure (Pa), rain gauge counter, anemometer counter.
Averaged wind direction is stored in a separate csv file. Samples are taken every ten seconds
for only one minute before values are converted (see Section 4.1.1), summed up, averaged
and stored to SD.
The shorter logging period is resulting from the noise in readings from the wind vane. As
mentioned above, the voltage output from the sensor may slightly change for one direction in
about some thousandths. By taking the average from 60 readings, noise is summing up as well
and could lead to misinterpretation. An example for that is shown in Figure 12.
Figure 12: Sample from windlog.csv. Values are: date, time, seconds since start, wind direction.
A summary of the costs for MC and all the devices is given in Table 10. The most expensive
part of the prototype is the Weather Sensor Assembly, however, it contains three sensors for
the station and a mast for installation. The total price of around 240€ makes the weather
station affordable for schools.
23
Item Price (€)
Arduino Mega 47
Ethernet Shield + 2GB micro SD card 45
Weather Sensor Assembly 60
SHT15 Breakout 35
BMP085 Breakout 17
Real Time Clock Module + Battery 10
Power Supply Unit 8
Waterproof case 12
Electrical accessories 10
Sum 244
Table 10: Material costs of the weather station prototype.
4.2 Integration into School Lessons
The project is aimed at high schools pupils of 15 years and older. It is possible to build up the
station from scratch with the construction manual during a project week. Basic knowledge
about technical engineering and programming are of advantage but not required.
A better way to integrate the weather station is to create a series of lessons in different school
subjects. An approach for a series of six school lesson in Physics, Computer Science and
Geography class, aligned with the educational standards, is given in this section.
Physics Lessons
Fundamentals of climatology can be explained in physics class. A concept for that is
described in [19] where teaching of thermodynamics is replaced by teaching in climatology.
Measurement methods are introduced according to the topic of each lesson. Topics for six
lessons can be found in Table 11.
Topic Content Activities
Introduction Climatic variables
Comparison of the
weather situation to
weather forecast,
recording of weather
observations
Temperature measurements
Measurement methods,
thermometer,
origins of differences in
temperature
Measurement of
temperature in the
environment (air
temperature, surface
temperature)
24
Air pressure, formation of
differences in pressure and
winds
Air density, measurement
methods, height dependency of
air pressure
Determination of density
/ pressure, experimental
measurements
Relationship between pressure
and temperature
Pressure and energy, calculation
of temperature gradients,
adiabatic changes in temperature
Experiments for (de-)
compression of gases
Clouds, steam and relative
humidity.
Temperature dependency of steam
pressure of water, absolute and
relative humidity, dew point
Experiment to
evaporation process,
steam pressure curve,
humidity measurements
Types of precipitation
Conditions of drop and crystal
formation, sink rate of
precipitation elements
Experiments for
crystallizations and sink
rates
Table 11: Topics for climatology school lesson in Physics. Modified from [19].
Computer Science Lessons
It makes sense for the schools to purchase Arduino starter kits besides the weather station
construction kit. With an Arduino starter kit, most of the functions that are needed to
understand how the station works can be learned in only one or two days. Some physical
fundamentals about electricity and the control of input and output are the most important
aspects at the beginning of the work with Arduino boards. It can be very useful to discuss the
functions of the Arduino controller and the single components before constructing the station.
Simple electric circuits should be realized to get in touch with the programming of the board.
A possible design for six school lessons is explained in Table 12.
Topic Content Activities
Introduction Arduino prototyping platform
Building and programming
simple circuits with an Arduino
MC
Communication methods Digital I/O, analog input
Experiments with different
communication methods, find
out about restrictions
Datalogging and wireless
communication
SD cards, XBee, GPS and
Arduino shields
Create data logging device,
collect position based data, log
data or use wireless connection
Web enablement Using Arduino as server and
client
Experiments for displaying
sensor values online, using a
browser to change configuration
of the Arduino board
25
Weather station Preparation for building up the
station
Project weather station:
construct, program and place
outside
Arduino contest Creating concepts for own
projects
groups working out project
ideas; best voted concept is
realized in future project
Table 12: Topics for a Arduino based series of Computer Science lessons.
Geography Lessons
In Geography lessons, the pupils are thematically prepared for finding a location for the
weather station and for analyzing the data. Therefore a top-down approach can be applied.
First, they learn about the global weather construct before going down to a regional layer.
Afterwards, effects on the climate in urban environments can be discussed before they have to
analyze their school campus in order to find an appropriate location for the weather station.
Finally, they learn about how to analyze and compare the weather data. In Table 13, a detailed
concept for a weather based teaching series is described.
Topic Content Activities
Weather process as part of the
atmosphere
Horizontal scales, circulation
systems
Describe layers of the
atmosphere in detail
Global Climate
Climate zones, ocean streams,
climate change, greenhouse
effect
Compare climate
scenarios, work out simple
climate model
Regional Climate
Regional influences on the
weather, topography of regional
environment
Identify regional climate,
compare to other climate
zones
Climate in urban environments
Heat islands, wind corridors,
horizontal, urban planning
process
Identify reasons for
microclimate, develop
plans for green cities in
groups
Choosing a location for the
weather station Urban site mapping
Finding best location on
the school campus, collect
metadata for the station
Weather analysis Different types of climate charts
Create climatic charts from
measurements, compare to
other schools
Table 13: Climatology teaching series in Geography class.
26
5. Evaluation
In this chapter, data from two logging sessions is compared reference station from the
Institute of Landscape Ecology (ILÖK) at the University of Münster. In addition to that, a
workshop for pupils was performed to find out whether children cope with the station or not.
5.1 Data Evaluation
The resulting data from the weather station prototype is compared to the data of a professional
weather station. As shown in Figure 13, the prototype was placed on the rooftop of the ILÖK
in the Robert-Koch-Straße in Münster. Over 300 series of measurements from around 50
hours are compared.
Figure 13: The prototype of the weather station was setup on the ILÖK in around 2,5m height.
The first measurement was recorded on 7th
of October at 10:40 and the last measurement one
day later at 14:20. After analyzing the data from that session, calibration of SHT15 and
BMP085 were slightly adjusted according to the results.
A second round of measurement started at 11th
of October at 13:40 and was performed until
12th
October at 12:50. The dashed line in the statistics marks the leap in time between the two
sessions.
27
Air Temperature
Results of the temperature readings are shown in Figure 14. In total, the tendency of the
temperature values from the SHT15 can be used to perform accurate temperature
observations. Sensor adjustment after the first series of measurements improved the results.
Figure 14: Temperature readings of SHT15 and ILÖK station.
Relative Humidity
At the beginning of the first measurement period the values of the relative humidity
measurement from the SHT15 seemed to be fitting to those of the ILÖK station. But as
displayed in Figure 15, the values of the sensor are breaking down at a point where 70% RH
is exceeded. The second measurement period is showing the same abnormality.
Figure 15: Humidity measurement of the SHT15 compared to ILÖK station values.
3
5
7
9
11
13
15
17
°C
Temperature ILÖK Temperature
SHT15 Temperature
0
10
20
30
40
50
60
70
80
90
100
% R
H
Humidity ILÖK Humidity
SHT15 Humidity
28
This problem may be solved by turning on the heating of the device at high RH values, but
this may also affect the measurement. It is also possible that the sensor has been damaged
during construction of the station. Exchanging the sensor should make that clear.
Air Pressure
The air pressure values of the ILÖK station are much more stable and linear than the readings
of the BMP085. The ILÖK's barometer is placed indoors at stable conditions. As described in
section 4.1.2, the pressure measurement is sensitive to temperature and humidity and should
be performed in an enclosed environment. The BMP085 was placed in the case together with
the MC outside on the rooftop of the institute. The idea was that the temperature in the case
does not vary as much as air temperature because it is heated slightly by the MC. Electrical
interferences could have affected the measurement additionally [11].
Figure 16: Pressure readings of the BMP085 and the ILÖK station.
For further testing the temperature of the BMPM085 could be logged as well to get
information about the conditions. Due to the fact that temperature compensation is included in
the algorithm for calculating the air pressure, it should normally not have such an effect on the
reading.
Precipitation
Due to the weather situation during both measurement periods, it was not possible to get
comparable measurements. Only at the end of the second time interval the bucket of the rain
gauge emptied once. At the same time the ILÖK station also recognized some rainfall. The
two values differ because of the different resolutions of the instruments.
980
990
1000
1010
1020
1030
1040
1050
1060
hP
a
Pressure ILÖK Pressure
BMP085 Pressure
29
Figure 17: Nearly no rain fall was measured by the prototype and the ILÖK station.
Wind Speed
Even though the behavior of both curves are nearly the same, wind speed measurements of
the prototype are below the values from the ILÖK station (Figure 18).
Figure 18: Wind speed measurements of the prototype and the ILÖK station.
A possible reason is that the anemometer of the ILÖK station was placed in a height of five
meters, whereas the anemometer of the prototype was placed in only two meter height. There
was an obstacle in the center of the rooftop next to the station which could have affected the
measurement. Even though this is not the case, approximation could be increased by including
an offset factor to the calulation.
Wind Direction
The wind directions measured by the prototype are varying strongly in short intervals. Again,
placement of the wind vane should be the reason for that.
-0,1
6E-16
0,1
0,2
0,3
0,4
0,5
0,6 m
m
Precipitation ILÖK Precipitation Prototype Precipitation
0
0,5
1
1,5
2
2,5
3
3,5
4
m/s
ec
Wind Speed ILÖK Wind Speed
Prototype Wind Speed
30
Placing the wind vane directly next to the ILÖK's vane has to be tested to proof that.
Figure 19: Wind direction measurements of the prototype and the ILÖK station.
For flattening the amplitude of the curve, a boxcar filter is applied to the measurement series
from the prototype indicated by the black solid line in Figure 19.
5.2 Practical Workshop
To evaluate the idea of bringing the weather station prototype to schools, it was integrated as
an example project into a holiday workshop from the GI@School initiative at the MExLab in
Münster on 24th
of April 2012. Topic of the course was “Mobile Sensors” in which high
school pupils of all ages participated. Main part of the workshop was an introduction to the
Arduino Uno MC and practical work with it during a six hour crash course. Besides the
technical part, the workshop was meant to convey understanding about the environment and
how observations can be used to visualize measurements. At the end of the course, a
questionnaire was given to participants to find out about their motivation and how they liked
the work with the Arduino boards in general but also about the introduced idea of building
and integrating a weather station in school class.
Procedure
Because of the young age of most of the pupils, the course was more focused on crafting than
on programming (see Figure 20). The programming part was kept quite simple. We showed
0
50
100
150
200
250
300
350
De
gre
es
Wind Direction ILÖK Wind Direction
Prototype Wind Direction
31
and explained them the code sketches, which they had to copy afterwards to get their setup
running. Nevertheless, the students were encouraged to discuss problems with the whole
group and had to come up with their own ideas, which we tried to implement together to keep
the course as dynamic as possible.
At the beginning of the workshop, we explained the Arduino boards in general and gave
examples for what they could be used for. After that, the pupils had to build simple electric
circuits and had to connect them to the Arduino controller board. This part of the lesson was
mainly to get in touch with different electric components like resistors, LEDs, buttons and
potentiometers and how they can be combined. For each setup, the controller board had to be
programmed according to the actual composition of components and connections to the board.
In the main part, the participants worked with environmental sensors. Input values from the
sensors were read out first and then used to control different output elements like LEDs,
speakers or a data logger. After the preparation part of the project we developed a mobile
sensor platform with a multicopter and an Arduino setup mounted on the drone to collect
location based temperature data (Figure 21).
After a successful implementation, it turned out that the self-construction of the platform also
motivated the pupils to do the theoretical data analysis part after a test run. The collected
datasets were visualized in a GIS as a final step of that project work.
Figure 20: The pupils were introduced to the Arduino Uno microcontroller.
32
Figure 21: The Parrot AR.Drone multicopter with the Arduino board, thermometer, GPS and radio
data transmitter.
As final presentation of the workshop, the concept of the DIY weather station was explained
to the pupils. With only some simple instructions and pictures they had to build up the
prototype by themselves. Observation during the construction should reveal how well they
cope with the provided instructions and if any problems occur using them. As mentioned
above a questionnaire had to be filled out to underline the observations.
Questionnaire
A short questionnaire was created to investigate how interesting the work with the Arduino
platform and with the weather station is for the pupils. It also included questions about the
pupils themselves and their technical experiences.
In total six pupils participated in the workshop. As shown in Figure 22 we had 83% male but
only 17% female participants. The youngest pupils in the group were two 12 years old
children while the oldest was already 18. Four of them were under, and two over 15 years of
age.
83%
17%
Gender
Male Female
Figure 22: In total more male than female pupils participated (a). 66% of the pupils were under
15 years.
33
As mentioned above the low ages of most of the participants made it difficult to discuss the
programming part in detail or making them work out the sketches for the different setups on
their own. According to that, only the oldest pupil would have preferred more programming
work during the course (Figure 23a). All others think that the mixture of tinkering and
programming was appropriate. But independent from age, all of them had fun during the
course and found the content interesting or very interesting (Figure 23b).
All of the pupils, which participated in the workshop liked the idea of a DIY weather station
and would like to have it integrated into school class. One of them as a project week and even
five as part of a longer series of lessons (Figure 24a). Figure 24b shows that the pupils are not
just interested in building up such a weather station, but also in further work with the
measurements and possible sensor upgrades.
Figure 24: All of the pupils would like to have the weather station integrated into class (a). Also all of
them are interested in additional work than just building the station (b).
0
1
2
3
4
5
6
Tinkering Was a good mix
Programing
Would you prefer more tinkering or more programing
in the course?
0
1
2
3
4
5
6
Very Interesting
Interesting Boring Very boring
How was the work with the Arduino Boards in total?
Figure 23: The mix of tinkering and programming was well chosen for the workshop (a) and
nearly all the pupils found the content very interesting (b).
34
Figure 25 underlines that the practical, technical work in high school classes is not just a good
idea for teachers to get the pupils’ attention. Furthermore, it is a motivation for the kids to
spend time on it non-obligatory. Not just the usage but especially the understanding of how a
computer system works will be one result in spending interest and time on projects with the
Arduino microcontrollers. The evaluation shows that the simplicity of imaging and integrating
a technical project could be learned and supported by the weather station project.
Figure 25: The motivation to work with the Arduino boards after the course was very high.
6. Conclusion
The goal of the thesis was to develop a weather station prototype and a concept for integration
in school lessons. The successful solutions and obstacles that occurred during the
development are discussed in this section.
6.1 Discussion
Basically the prototype fulfils all requirements, but with some limitation. The reporting of
observations is working in principle, but representativeness is strongly dependent on the
measurements accuracy. Until now, it is not possible to get accurate measurement from all the
sensors of the station, even though, all the sensors were tested independently. Hardware
testing was performed throughout all stages of the project. The costs of the hardware setup
presented in this thesis are around 240€, which could be further reduced by using cheaper
sensors. By cutting the cost of the basic station, more budged is left for sensor upgrades.
Technically, the hardware provides much more input possibilities than actually used by the
sensors of the weather station. If schools do not want to integrate the idea for a series of
lessons around this topic, it is easily possible to modify the station for different means. All
0
1
2
3
4
5
6
Yes and I already did
Yes, the course inspired me
Essentialy yes, but not with
Arduino
No interest at all
Can you imagine to work with the Arduino boards in you freetime?
35
needed instructions are provided by the DIY manual. In addition, wiring examples and
software sketches for single sensor setup can be found in the appendix.
6.2 Future Work
The weather station is leading the way to a project based type of teaching in schools. It is only
one example for realizing own ideas with few and simple means. As the work of GI@School
is demonstrating, teachers and pupils are eager for new and creative ideas in their lessons. The
next step for a successful integration to schools would be to embed the DIY weather station to
a larger chest of DIY projects. A bachelor's thesis about a general DIY project also based on
the Arduino Platform is currently in work by Sergey Mukhametov at the ifgi. The weather
station could easily be integrated to become a part of the work.
To share weather data between participating schools, a network has to be established.
Infrastructures like GLOBE or the SenseBox Portal already exists and could be used for that.
Further testing has to be done to integrate the weather station into the web. Additional testing
should also be performed to improve the accuracy of the measurements and to verify the long
term stability. As this is very time consuming, one idea is to let the students in the schools
work directly on these topics and let them become Citizen Scientists.
36
References
[1] German Association for Information Technology, Telecommunications and New
Media, 2011: Jugend 2.0: Eine repräsentative Untersuchung zum Internetverhalten
von 10- bis 18-Jährigen. BITCOM, Berlin.
[2] Bröring, A., Remke, A., Lasnia D., 2011: SenseBox: A Generic Sensor Platform for
the Web of Things. Institute for Geoinformatics, Münster.
[3] GI@School: Homepage. Online:
http://www.gi-at-school.de (last accessed on 2nd October 2012).
[4] Open Source Initiative: The Open Source Definition. Online:
http://opensource.org/docs/osd (last accessed on 2nd October 2012).
[5] Open Source Hardware Association: OSHW Definition. Online:
http://www.oshwa.org/definition (last accessed on 2nd October 2012).
[6] Definition of Free Cultural Works: Open Source Hardware. Online:
http://freedomdefined.org/OSHW (last accessed on 2nd October 2012).
[7] Arduino: Homepage. Online:
http://arduino.cc/en/ (last accessed on 2nd October 2012).
[8] Arduino: Reference. Online:
http://arduino.cc/en/Reference/HomePage (last accessed on 2nd October
2012).
[9] Oxer, J., Blemings, H., 2009: Practical Arduino: Cool Projects for Open
Source Hardware. Apress.
[10] World Meteorological Organization: Homepage. Online: http://www.wmo.int (last
accessed on 4th October 2012).
[11] World Meteorological Organization, 2008: Guide to Meteorological Instruments and
Methods of Observation. WMO-No. 8, Geneva.
[12] Oke, T.R., 2006: Initial Guidance to Obtain Representative Meteorological
Observations at Urban Sites. World Meteorological Organization, Instruments and
Observing Methods, IOM Report No. 81, WMO/TD-No. 1250.
[13] Bailey, W.G., Oke, T.R., Rouse W.R., 1997: The Surface Climates of Canada.
McGill-Queen’s University Press, Montreal, chapter 13.
[14] World Meteorological Organization, 1992: International Meteorological Vocabulary.
Second edition, WMO-No. 182,Geneva.
[15] Conference of the German Ministers of Education and Cultural Affairs, 2005:
Bildungsstandarts der Kultusministerkonferenz: Erläuterungen zur Konzeption und
Entwicklung. Luchterhand, Munich.
37
[16] Hemmer, I., Hemmer, M., Rhode-Jüchtern, T, Ringel, G., Schallhorn, E., 2006:
Bildungsstandards in Fach Geographie für den Mittleren Schulabschluss. German
Association for Geography, Berlin.
[17] Brinda T. Fothe, M., Friedrich, S., Koerber, B., Phulmann, H., Röhner, G. Schukte, C.,
2008: Bildungsstandards Informatik für die Sekundarstufe I. LOG IN, Volume 28,
Nr. 150/151, German Association for Computer Science.
[18] Conference of the German Ministers of Education and Cultural Affairs, 2005:
Bildungsstandards im Fach Physik für den Mittleren Schulabschluss. Luchterhand,
Munich.
[19] Heinz Muckenfuß, 1997: Wetterkunde statt Wärmelehre. Naturwissenschaften im
Unterricht Physik, Volume 42, Nr. 8, pp. 4-8.
[20] Silvertown, J., 2009: A new Dawn for Citizen Science. Trends in Ecology & Evolution,
Volume 24.
[21] Citizen Science as Participatory Science. Online:
http://povesham.wordpress.com/2011/11/27/citizen-science-as-participatory-
science (last accessed on 4th October 2012).
[22] Galaxy Zoo. Online: http://www.galaxyzoo.org (last accessed on 4th October 2012).
[23] Sloan Digital Sky Survey. Online: http://www.sdss.org (last accessed on 4th October
2012).
[24] About GLOBE. Online: http://www.globe.gov/about-globe (last accessed on 4th
October 2012).
[25] LEGO Education: 8+ LEGO Mindstorms Education. Online:
http://education.lego.com/en-us/preschool-and-school/upper-primary/8plus-
mindstorms-education (last accessed on 4th October 2012).
[26] Arduino: Arduino Board Mega 2560. Online:
http://arduino.cc/en/Main/ArduinoBoardMega2560 (last accessed on 13th October
2012).
[27] Arduino Reference: Wire Library. Online:
http://arduino.cc/en/Reference/Wire (last accessed on 13th October 2012).
[28] Arduino Reference: SPI Library. Online:
http://arduino.cc/en/Reference/SPI (last accessed on 13th October 2012).
[29] Arduino: Arduino Ethernet Shield. Online:
http://www.arduino.cc/en/Main/ArduinoEthernetShield (last accessed on 13th
October 2012).
[30] Arduino: Ethernet Library. Online:
http://arduino.cc/en/Reference/Ethernet (last accessed on 13th October 2012).
[31] Arduino: SD Library. Online: http://www.arduino.cc/en/Reference/SD (last accessed
on 13th October 2012).
38
[32] Sensirion AG: Humidity Sensor SHT15. Online:
http://www.sensirion.com/en/products/humidity-temperature/humidity-sensor-sht15
(last accessed on 9th October 2012).
[33] Sensirion AG: SHT15 Datasheet. Online:
http://www.sensirion.com/fileadmin/user_upload/customers/sensirion/Dokumente/
Humidity/Sensirion_Humidity_SHT1x_Datasheet_V5.pdf (last accessed on 9th
October 2012).
[34] SparkFun Electronics: Humidity and Temperature Sensor - SHT15 Breakout. Online:
https://www.sparkfun.com/products/8257 (last accessed on 9th October 2012).
[35] Practicalarduino on github: SHT1x Library. Online:
https://github.com/practicalarduino/SHT1x#readme (last accessed on 13th October
2012).
[36] Bosch Sensortec: Pressure Sensors. Online:
http://www.bosch-sensortec.com/content/language1/html/3477.htm (last accessed
on 9th October 2012).
[37] Bosch Sensortec: BMP085 Datasheet. Online:
http://www.bosch-sensortec.com/content/language1/downloads/BST-BMP085-
DS000-06.pdf (last accessed on 9th October 2012).
[38] Google Project Hosting: Arduino driver for BMP085. Online:
http://code.google.com/p/bmp085driver (last accessed on 13th October 2012).
[39] SparkFun Electronics: Weather Meters SEN-08942. Online:
https://www.sparkfun.com/products/8942 (last accessed on 13th October 2012).
[40] SparkFun Electronics: Weather Sensor Assembly Datasheet. Online:
http://www.sparkfun.com/datasheets/Sensors/Weather/Weather%20Sensor%20Ass
embly..pdf (last accessed on 13th October 2012).
[41] Seeed Studio: Grove - RTC. Online:
http://www.seeedstudio.com/depot/grove-rtc-p-758.html (last accessed on 13th
October 2012).
[42] Seeed Studio: Grove - RTC Wiki Page. Online:
http://www.seeedstudio.com/wiki/index.php?title=Twig_-_RTC (last accessed on
13th October 2012).
[43] Adafruit on github: RTClib Library. Online:
https://github.com/adafruit/RTClib (last accessed on 13th October 2012).
i
A. Appendix
A.1. Software
This section lists the software applications that were used for the development of the
prototype and for writing this thesis.
Arduino IDE The Arduino IDE has been used implementation of the Arduino program code.
Homepage: http://arduino.cc/en/Main/Software
Fritzing The Fritzing software has been used as tool for designing circuits.
Homepage: http://fritzing.org/
Word The thesis has been written with Microsoft Word.
Homepage: http://office.microsoft.com/en-us/word
Excel Statistical analysis have been done with Microsoft Excel.
Homepage: http://office.microsoft.com/en-us/excel
PowerPoint Some of the figures have been created with Microsoft PowerPoint.
Homepage: http://office.microsoft.com/en-us/powerpoint
GIMP GIMP was used for vector image manipulation.
Homepage: http://www.gimp.org
A.2. Data CD
The compact disc attached to this thesis includes a digital appendix. Data stored in it is
described in this section.
Instructions A manual for installing the Arduino IDE and the libraries.
Location: cd:\
Arduino IDE Folder containing the Arduino IDE.
Location: cd:\ArduinoIDE\
Construction Manual The DIY construction manual for the Weather SenseBox.
Location: cd:\DIYmanual\
Arduino Libraries Libraries needed to compile the code of the weather station.
Location: cd:\Libraries\
Arduino Source Code The developed software sketches for each sensor and the whole station.
Location: cd\SourceCode\
Questionnaire The questionnaire, used at the workshop.
Location: cd:\Questionnaire\
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