educating the educators for introducing internet of things to...
TRANSCRIPT
Educating the Educators for Introducing Internet of Things to Primary and Secondary Schools'
Curriculums
Aleš Jaklič University of Ljubljana/Faculty of Computer and Information Science, Ljubljana, Slovenia
Abstract - We describe an approach to continuous education course at the University of Ljubljana for training of computer science and technology teachers in primary and secondary schools. These teachers face numerous challenges how to present computer science and engineering as a dynamic and interesting field to their students. Our approach is based on idea to introduce computer science and engineering by building Internet of things devices. A low-cost open source NodeMCU hardware and firmware platform based on ESP8266 is used, that provides WiFi connectivity and Lua interpreter as programming language. Raspberry Pi is used as a central hub for IoT devices. Teachers build an IoT system for monitoring indoor temperature and humidity, outdoor temperature and controlling an air-conditioner using IR control. Finally, we present the course evaluation by the teachers.
Keywords - IoT; teachers; primary school; secondary school; ESP8266; NodeMCU; smart home
I. INTRODUCTION Ministry of Education, Science and Sport in Republic
of Slovenia organizes continuous education courses for teachers in primary and secondary schools. The courses are offered at the universities, which apply each year to a call for proposal for courses - workshops. The courses typical length is 24 hours spread over several days, for example 3 x 8 hours or 4 x 6 hours. The courses are usually delivered on Saturdays so that they not interfere with teachers’ pedagogical processes in their schools.
Faculty of computer and information science at University of Ljubljana each year organizes Summer school for children from primary and secondary schools as an outreach program. Due to limited class sizes in the summer school programs we decided to scale out the provided curriculum to primary and secondary educational level.
Ideally, all these efforts should combine to establish an engineering pipeline [1] as a pathway of activities geared towards motivating students all through primary and secondary school to choose an engineering discipline at university level.
Numerous recent publications [2]–[4] in the field of education stress the importance of educating the Internet-of Things generation about IoT technologies since they present important opportunities for novel applications in various fields [5].
The rest of the paper is organized as follows: in section II we present a practical use case used for the course in detail, in section III we present the evaluation of the course, followed by section IV with conclusions.
II. USE CASE FOR THE COURSE – SMART APARTMENT To increase motivation of participants we selected a
practical use case of IoT application in a smart home. We wanted to remotely monitor temperature inside an apartment, outside temperature and be able to turn on/off an air-conditioner to heat or cool the apartment. In this way we can return home to cooled or heated apartment after summer or winter holidays.
The use case offers ample opportunities to teach basics of IoT, that is TCP/IP protocol, IP addressing, HTTP protocol, WWW servers, basics of HTML, Lua programming language, event driven programming and basics of PHP programming.
Figure 1 depicts the hardware system architecture of a smart apartment.
Figure 1. System architecture of a smart appartment
The whole system consists of two subsystem parts:
1. temperature and humidity sensors and
2. an actuator part to turn on/off heating or cooling (IR transmitter and a smart plug).
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A. Temperature and humidity sensors Three ESP8266 microcontrollers (two Wemos D1
minis (Figure 1), one ESP-01) with WiFi interface were used as sensor IoT nodes to monitor temperature in two rooms and outdoors. For details about implementation see [6].
Figure 1. Pinout of a compact version of NodeMCU hardware development board – D1 mini
The IoT node that measures outdoor temperature uses a sensor DS18B20+ with parasitic power harvesting, so that we can use only two existing wires for connecting the sensor on the outer wall of the apartment. The other two sensor IoT nodes use the DTH22 and a regular DS18B20+ sensor locally on a protoboard. Figure 2 shows one of the sensors nodes implemented with ESP-01 using existing wiring for the temperature sensor.
Figure 2. IoT node with ESP-01 and parasitically powered temperature sensor DS18B20
A Raspberry Pi single board computer running Linux is used as a central IoT node that collects data from sensor nodes over HTTP and also serves collected data in a form of a Web page (Figure 3). Each of the sensor nodes has a small WWW server implemented in Lua [6].
A simple PHP script that runs on Raspberry Pi Apache web server provides aggregated data to the user, together with uptimes of the system’s components (Figure 3).
Figure 3. Temperature and humidity measurements presented through a Web interface
B. Actuators – IR transmitter on Raspberyy Pi and smart plug
The Raspberry Pi also serves as an actuator by sending IR commands to the air-conditioner. Instead of reverse engineering the IR protocol to control the air conditioner, we recorded the IR signal from the IR remote, that was set to cooling or heating. Then we played back these signals using IR transmitter LED diode. Figure 4 shows a setup with an IR receiver and air-conditioner IR remote for signal capture.
Figure 4. IR command protocol recording on a Raspberry Pi 4
We used sudo ir-ctl -d /dev/lirc1 –receive command to record the signal from the IR remote controller in a form of pulses and spaces with corresponding timing parameters. The sequence was then further processed in MS Excel to make the measured timing parameters consistent. Finally, the sequence was included into open source IR slinger library [7] for sending the IR command
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through IR diode connected to Raspberry Pi through a transistor (Figure 5).
Figure 5. IR LED diode connected to Raspberry Pi as a part of IR transmitter
To provide additional layer of security and power savings we connected the air-conditioner through a smart plug (Figure 6.). In this way we can monitor with an Android mobile application Smart Life the power consumption of the air-conditioner and check to see if it is really turned on or off (Figure 7.)
Figure 6. Wi-Fi smart plug XP1030 used to control and monitor AC power to the air-conditioner
Control of the air conditioner is achieved by a simple WWW user interface (Figure 8) implemented in PHP on Raspberry Pi, that runs corresponding IR slinger commands.
Figure 7. Screencapture of Android application to switch AC power on/off and monitor AC power to the air-conditioner
Figure 8. Screen capture of simple Web GUI to control the air-conditioner
Finally, we can monitor how temperature changes over time using ThingSpeak [8] visualizations of stored temperature and humidity data (Figure 9 and Figure 10). Each sensor node sends its measurements to ThingSpeak cloud over HTTP.
Figure 9. Change of temperature inside the appartment over last 48 hours as presented by ThingSpeak
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Figure 10. Change of temperature outside the appartment over last 48 hours as presented by ThingSpeak
III. EVALUATION OF THE COURSE BY TEACHERS
In total 13 teachers, 7 from primary schools, 8 from secondary schools, participated in the course over the two years in 2018 and 2019. Teachers were given source code templates to accelerate the development of required Lua code.
Tables below presents the evaluation of the course by the teachers regarding: a) content and presented methods (Table I), b) applicability of the presented approach (Table II).
TABLE I. SURVEY OF CONTENT AND METHODS OF WORK
No Sample size (N = 13, Grade scale 1 – 10)
Statement Average Grade
1. Program introduces new and fresh ideas 8,84
2. Previous experience of participants were considered
9,00
3. I will be able to use new knowledege in practice
8,84
4. Course materials are of apropriate quality 8,69
Average grade for content and methods 8,84
TABLE II. SURVEY OF APPLICABILITY OF THE EDUCATION PROGRAM
No. Sample size (N = 13, Grade scale 1 – 10)
Statement Average Grade
1. With the program I gained new theorethical knowledege 8,69
2. The program motivated me to introduce changes in my work
8,31
3. The program ofered practical solutions for work
8,77
4. The program opens new questions and encourages continuing education in the field
8,08
Average grade for applicability 8,46
The results show a strong viability of our approach to use creation of useful IoT devices as an introduction to computer science and engineering.
IV. CONLUSIONS The approach presented in the paper was well received
by teachers. The use case of smart apartment introduces all basic IoT technologies and components. Also, the cost of all components is very low and thus suitable for implementation in classes and workshops. The ESP8266 WiFi modules running NodeMCU proved to be reliable with uptimes of several months. The Raspberry Pi running Linux as a central hub also displayed remarkable robustness with good uptimes.
However, there are also a few drawbacks when using ESP8266. The first one is relatively large energy consumption due to WiFi transmission, and this need special consideration when using battery power. The second drawback is that is its rather hard to use HTTPS in NodeMCU Lua since it requires a significant amount of RAM to establish a HTTPS session. We might alleviate this problem by using compiled Arduino language instead of Lua interpreter of NodeMCU or using ESP32
REFERENCES [1] T. Odun-Ayo and T. Obafemi-Ajayi, “Building the K-12
engineering pipeline: An assessment of where we stand,” in Proceedings - Frontiers in Education Conference, FIE, 2017, vol. 2017-October, pp. 1–9.
[2] A. Mavroudi, M. Divitini, F. Gianni, S. Mora, and D. R. Kvittem, “Designing IoT applications in lower secondary schools,” in IEEE Global Engineering Education Conference, EDUCON, 2018, vol. 2018-April, pp. 1120–1126.
[3] J. R. Byrne, K. O’Sullivan, and K. Sullivan, “An IoT and Wearable Technology Hackathon for Promoting Careers in Computer Science,” IEEE Trans. Educ., vol. 60, no. 1, pp. 50–58, Feb. 2017.
[4] D. Glaroudis, A. Iossifides, N. Spyropoulou, I. D. Zaharakis, and A. D. Kameas, “STEM Learning and Career Orientation via IoT Hands-on Activities in Secondary Education,” in 2019 IEEE International Conference on Pervasive Computing and Communications Workshops, PerCom Workshops 2019, 2019, pp. 480–485.
[5] J. Voas and P. Laplante, “Curriculum considerations for the internet of things,” Computer (Long. Beach. Calif)., vol. 50, no. 1, pp. 72–75, Jan. 2017.
[6] A. Jaklič, “IoT as an Introduction to Computer Science and Engineering: A Case for NodeMCU in STEM-C Education,” in 2020 IEEE Global Engineering Education Conference (EDUCON), 2020, pp. 91–95.
[7] “GitHub - bschwind/ir-slinger: A small C library for sending infrared packets on the Raspberry Pi.” [Online]. Available: https://github.com/bschwind/ir-slinger. [Accessed: 14-Feb-2020].
[8] “IoT Analytics - ThingSpeak Internet of Things.” [Online]. Available: https://thingspeak.com/. [Accessed: 09-Dec-2019].
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