6th International Conference on Education and New Learning Technologies Barcelona - 7th - 9th of July 2014 FLEXIBLE PLATFORMS FOR TEACHING EMBEDDED SYSTEMS Liviu Breniuc, Cristian-Győző Haba Faculty of Electrical Engineering “Gheorghe Asachi” Technical University of Iasi

Introduction Following the tremendous evolution of the microelectronic and IT technologies, the embedded measurement systems have started to incorporate large sets of features and functionalities. Measurement systems have become faster and more accurate with the advent of new categories of intelligent sensors. These systems incorporate now electronics that implement a great part of conditioning, processing and filtering, tasks that were once taken in charge by the computing system to which the sensors were connected. 6th International Conference on Education and New Learning Technologies Barcelona - 7th - 9th of July 2014

Introduction We present our work for developing a flexible platform for teaching embedded systems and two tools (covering matrix and oriented graph) associated to the flexible platform that can be used to develop the learning paths for one or more related courses. For demonstration it is presented a flexible platform which can be used in applications that measure, process and record quantities that characterize the environment status. 6th International Conference on Education and New Learning Technologies Barcelona - 7th - 9th of July 2014

Platform description Authors have developed several embedded systems that can be used for teaching purposes. The platforms are composed of several modules that can communicate using an RF connection. Each platform has a central processing unit that is implemented using a microcontroller or FPGAs development board and several extension modules that extend the feature set of the development board. Changing or adding sensor modules to a sensor node can modify or enhance the node functionality. The platform use smart sensors that can communicate with a microcontroller via SPI, I2C, UART ports. 6th International Conference on Education and New Learning Technologies Barcelona - 7th - 9th of July 2014

Platform description For demonstration purposes we will present our last developed flexible platform aimed for teaching embedded systems targeted for environmental measurements. The flexible platform, denoted as EMBENVP, consists of several sensor nodes that measure physical quantities, make an A/D conversion and communicate the conversion result to the central unit that can process, display and store this data from the nodes. Using this platform the students can learn the following: programming the microcontroller board using C or C++, communicating with the smart sensors using the SPI, I2C or UART ports, creation of a sensor network based on a custom designed or a known communication protocol such as ZigBee or MiWi. 6th International Conference on Education and New Learning Technologies Barcelona - 7th - 9th of July 2014

EMBENVP System Cerebot Nano Cerebot Nano PmodRF1 HEF4052 SHT21 LED COZIR GSS Sensor MAX44009 Cerebot MX3ck PmodRF1 PmodCLP PmodSD PmodGPS Bateries RF link 8 USB link PC + software Sensor node module Station module Bateries

Sensor node module (SN) Built around a Cerebot Nano development board from Digilent. The SN can contain several sensors, the exact number and type depend of the application. One SN module we have built contains the following components: – temperature and humidity sensor SHT21 from Sensirion, – COZIR carbon dioxide sensor from GSS (Gas Sensing Solution) mounted inside, – eight MAX44009 ambient light sensors (ALS) from Maxim, – PmodRF1 module from Digilent for RF communication with the station – 3.7 V Lithium Ion Battery. – RS232 adapter or a Pmod USBUART converter also from Digilent used for development, debugging and verification. Cerebot Nano Cerebot Nano PmodRF1 HEF4052 SHT21 LED COZIR GSS Sensor MAX Bateries 6th International Conference on Education and New Learning Technologies Barcelona - 7th - 9th of July 2014

Station module (ST) Built around the Cerebot MX3ck development board from Digilent. Includes: – PmodRF1 radio transceiver module for communication with sensor nodes – PmodGPS module for mapping measured data – PmodCLP LCD display – PmodSD interface for SD card which is used for recording the measured data. The station can be connected to a PC using an USB port. The connection is used for development, debugging and verification of the software application running on the ST or for transferring recorded data. Cerebot MX3ck PmodRF1 PmodCLP PmodSD PmodGPS Bateries 6th International Conference on Education and New Learning Technologies Barcelona - 7th - 9th of July 2014

Platform operation SN module measures temperature, humidity, carbon dioxide level and sunshine duration and send data to ST module. Flashing LEDs on the ST and SN modules indicates that the communication is established between the two modules. Results of current measurement are displayed on LCD display of ST module: – battery level, – temperature in °C, – relative humidity, – no presence of sun, – maximum and minimum illumination, – carbon dioxide level. Because space available on LCD display is limited, on the second line of display is showed alternatively illumination and carbon dioxide level respectively. 6th International Conference on Education and New Learning Technologies Barcelona - 7th - 9th of July 2014

EMBENVP system with a sensor node module oriented to environmental parameter measurements Batteries LCD Display GPS receiver and antenna Sensor node module Cerebot MX3ck SD Card Slot RS232 interface RF transceiver

Educational use The aim of building the platform was to provide a support for multiple laboratory works that introduce students to different well established or emergent hardware and software technologies. The architecture of the platform evolved from different other platforms that have been used for teaching purposes but which were aimed at measuring only one parameter such as temperature or humidity. The platform is conceived to support laboratory works for students in the Instrumentation and Data Acquisition and the Applied Computer Science specializations. 6th International Conference on Education and New Learning Technologies Barcelona - 7th - 9th of July 2014

Covering matrix The different platform features can be associated to specific topics that are included in the courses taught in these two specializations. Covering matrix encodes relationship between features (f) covered in courses (c) x sign in cell (f,c) indicates that platform feature f covers a topic in course c and thus can be use for demonstration of that topic during a lab work using the proposed platform. 6th International Conference on Education and New Learning Technologies Barcelona - 7th - 9th of July 2014

Covering matrix for EMBENVP system Courses Platform Features Electrical Measurements Digital Systems Data Acquisition Microcontrollers Programming Object Oriented Programming Intelligent Sensors Communication Systems Real Time Systems Distributed Systems Signal Processing Microcontrollers xxxxxxxxxx Digital I/O xxxxx Analog I/O xxxxx Timers xxxxx Real Time Clock xx Communication protocols xxx UART xxxxx I2C xxxxx SPI xxxxx RF custom xxx RF ZigBee xxx Data display xxx Temperature meas. xxxx Humidity meas. xxxx Dew Point meas. xxxx Position meas. xxxx Network topologies xx C programming xxxx C++ programming xxxx Power saving xxxxxx

Discussion Analysis of the covering matrix shows that: – platform features contribute unevenly to different courses – the structure and content of the covering matrix depends on the courses content established by the teachers. – structure and content of the covering matrix depends on the structure of the sensor node (set of sensors and functional modules) 6th International Conference on Education and New Learning Technologies Barcelona - 7th - 9th of July 2014

Teaching process Laboratory works were developed to gradually introduce the students into the topic of embedded systems. With basic notions achieved, the system is then extended based on a modular design which enables the addition of new devices and features that turns the system into one capable to measure environment quantities such as temperature, humidity, illumination, sun duration, CO2 levels etc. Topics must be presented to students in a gradual way based on topics complexity, interrelationships as well appropriateness established by course curricula and teacher's vision on the course development. 6th International Conference on Education and New Learning Technologies Barcelona - 7th - 9th of July 2014

Oriented graph Considering the set of topics that a teacher can demonstrate using a flexible platform and the relationships between these topics, we can create an oriented graph that cover the many learning paths a teacher can take by using the flexible platform. An oriented graph can be constructed where each topic is a node in the graph and an oriented edge exists between two nodes if a relationship exists between the two. An oriented edge will exist from topic a to topic b if: – topic b can be presented only after topic a is presented, – topic b is more complex then topic a, or – any other such relationships. The oriented graph thus can depict the learning paths a teacher can take given a set of topics and the relationships between these topics. 6th International Conference on Education and New Learning Technologies Barcelona - 7th - 9th of July 2014

Oriented graph for EMBENVP system

6th International Conference on Education and New Learning Technologies Barcelona - 7th - 9th of July 2014 Learning path in oriented graph

6th International Conference on Education and New Learning Technologies Barcelona - 7th - 9th of July 2014 Two alternative learning paths in oriented graph

Conclusions Development of laboratory equipment to offer the basic training but also an up to date image of the problems encountered in real life is a constant concern for university teachers. A flexible platform for teaching embedded systems oriented through environmental quantities measurement is proposed. The students enrolled in two specializations of our faculty were gradually introduced into the topics of embedded systems by using this platform. 6th International Conference on Education and New Learning Technologies Barcelona - 7th - 9th of July 2014

Conclusions (2) The large number of devices, modules, technologies and features included in the platform allow teachers to select various learning paths that can be adapted to several courses offered by our university. Based on the particularity of the course, teachers can decide which module should be discussed in detail (schematic, operation, configuration, debugging etc) and which ones should be considered only as a black box.

Conclusions (3) During laboratory works the students showed a good interested in the applications developed with the proposed platform and confirmed that the learning curve was lean enough to understand the topics to be demonstrated and acquire the required skills. The authors are currently working on defining the metrics that will allow a better evaluation of the platform and on developing a methodology for the selection of optimum set of learning paths for each of the courses included in the covering matrix. 6th International Conference on Education and New Learning Technologies Barcelona - 7th - 9th of July 2014

Invitation 2014 International Conference on Electrical and Power Engineering, October 16-18, 2014 Iasi, Romania IEEE technical sponsored conference