Microcontrollers in Physics education: a circuit simulation ... - ICL

Conference ICL2010 

September 15 -17, 2010 Hasselt, Belgium 

Microcontrollers in Physics education: a circuit simulation 

designed to teach electric current 

Despina M. Garyfallidou 

The Science Laboratory, School of Education, University of Patras, Greece 

Key words: microcontrollers, simulation, science education, electricity. 

Abstract: 

In this paper a microcontroller-driven emulator board of a novel design is presented. 

The microcontroller has been programmed to detect the position of the switch-onboard, 

in combination to the presence or absence of electric current (either DC, or 

AC) and accordingly to drive some Light Emitting Diodes (LEDs) representing the 

moving electrons within the “circuit wires” emulated on the educational board. A 

teaching sequence, suitable for in order to teaching simple electrical circuits, has 

been carefully designed. During teaching, some material which had been designed by 

the author at an earlier time (and is available on-line) was used. The educational trial 

followed, testing together the on-line material in combination with the new 

microcontroller-driven device. The first results of this educational trial are presented 

herein. 

1 Introduction 

Research in science education has shown that children face difficulties in understanding the 

movement of electrons during the electric current 1 , 2 . This is because the electron movement 

is something that children cannot see or feel with their senses. Different (mental models 

representing this physical phenomenon have been used in order to help children to understand 

this idea, each one of which seemingly having its own problems, to illustrate adequately this 

rather abstract phenomenon without introducing new misunderstandings. 

In this paper a new hardware device simulating the movement of electrons in a circuit is 

presented. A new board, driven by a microcontroller, has been designed manufactured and 

implemented didactically, to teach the concept of electron movement. The microcontroller 

onboard has been programmed to detect the presence or absence of electric current (either 

DC, or AC) and drive some Light Emitting Diodes (LEDs) which represent the moving 

electrons (picture 1). Later, a teaching sequence was carefully designed, using this device as 

well as some material having been designed previously by the author 3 and already available 

online i . Subsequently, the educational trial took place, some results from which are presented 

herein. 

2 The device in detail 

The new device was constructed in cooperation with a Greek company specialising in 

electronics development. After considerable discussions between the author that defined the 

educational specifications and the company that defined the technically feasible 

i www.garyfallidou.org 

ICL 2010 Proceedings – Page 410 

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specifications, the shape of the new device was defined. The most important of user 

requirements for the new device was to make a clear and obvious distinction between the light 

bulb and whatever was to be used to represent the free electrons. It was decided to use a 

familiar-to-students laboratory type incandescence lamp on the circuit, while SMD-type 

(Surface Mounted Device) LEDs (i.e. very small and flat Light Emitting Diodes) were used 

for the representation of the electrons. 

These 32 LEDS have been placed about 1cm apart in the surface of a circle and the space 

between them (that means the rest of the circle) has been painted red. This red line with the 

red LEDs embedded in it represents the cables of the circuit on the emulator board. The red 

colour was chosen on purpose, as it is the same with that of the cables used in the streaming 

video (presented during the lesson) that shows how to construct a simple electrical circuit 

with a light bulb. 

The use of this new device in class allows students an opportunity to experiment and observe 

the phenomena simulated, something that could not be performed in any other setup in any 

class or school laboratory 4 , while at the same time allowing some surreal perception as to the 

electron movement. Therefore, the new device may be proven to be of high educational value. 

It is also exciting enough to attract the student’s attention. 

It is more beneficial to the students if the use of the device is incorporated in a teaching 

sequence dealing with electric circuits, and electric current. To this purpose, during the trial, 

already existing material like the one previously prepared and residing at 

www.garyfallidou.org was used. A teaching sequence using this online material had already 

been developed and tested in class 3 . It was precisely that previous educational trial that 

revealed the necessity of a device that allows the visualisation of the electron movement. The 

already existing teaching sequence was, therefore, suitably modified to incorporate the new 

device. 

The device is safe and “easy-to-use” even by very young students and, although it is 

microcontroller driven, it does not require any computer knowledge. Nevertheless, when used 

in classroom, it would be better for the teacher to study carefully the online material and 

decide which parts he/she wishes to use. The new device is about the size of child’s notebook, 

and is lighter than a book (at least lighter than the majority of the books Greek students carry 

in their bags). 


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Picture 1. 

The new device consists of a microcontroller, 32 LEDs, a light bulb, a switch and an 

electricity sensor. An external source (either AC or DC) can be physically connected to this 

sensor, both to provide power and to get noticed by the students who handle it (Picture 1). A 

microcontroller is a small computer on a single integrated circuit (IC - chip) containing a 

processor core, memory, and programmable I/O peripherals. Some PROM memory is often 

included as well as a small amount of RAM. A microcontroller is a kind of miniature 

computer. Microcontrollers are used in many household electronic devices, as they are 

designed for embedded special purpose applications, in contrast to the microprocessors which 

are used for general purpose applications like in personal computers. 

The specific microcontroller used on the device has been programmed to sense 7 distinct 

cases: 

a) The presence of DC current clockwise and the switch in the “on” position 

b) The presence of DC current counterclockwise and the switch “on” 

c) The presence of DC current clockwise and the switch “off” 

d) The presence of DC current counterclockwise and the switch “off” 

e) The presence of AC current and the switch “on” 

f) The presence of AC current and the switch “off” 

g) The absence of electric potential (either from an empty battery or no existence of source). 

In this case, the position of the switch is indifferent because the circuit is open anyway, and 

the microcontroller drives the LEDs and the light bulbs accordingly. 

If the circuit is closed (as in the cases a, b, e) the microcontroller flashes the LEDs 

successively following the direction from the positive pole of the battery to the negative one 

and illuminates the light bulb. If the circuit is open (case c, d, f and g) the microcontroller 

flashes the LEDs randomly (to simulate random motion) and the light bulb does not 

illuminate. 


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Picture 2. 

In picture 2 the back of the device appears. The microcontroller and the battery that provides 

energy to the board can be seen. Effort was paid so as this battery to be as indistinct and 

obvious to the user as possible. 

3 Connecting theory with experimental observation 

As already mentioned, a teaching sequence has been specially developed. At the beginning 

students were asked to create a simple circuit. For this reason, students worked in pairs. Most 

of them failed to create a simple circuit without the help from the video. After watching the 

streaming video, students were asked to consider what is happening when a battery is 

connected to the circuit, which causes the light-bulb to shine. Then the new device was 

presented to the students and the underlying theory was explained to them. 

At the beginning the device simulated the absence of battery. Students learn in theory that 

“when no battery is connected to the circuit, the electrons move randomly and the light bulb 

does not illuminate”. In the emulator various LEDs are quickly switched on and off at random 

order, while the light bulb does not illuminate. 

The theory says that: “As soon as a battery is connected to the circuit and the circuit closes, 

which means that all cables are connected properly, and the switch is on, the potential 

difference (voltage) applied to the circuit from the battery forces the free negatively charged 

electrons to move from the point with the low potential, to the one with high potential – in 

other words from the negative pole of the battery to the positive one. This flow of electrons is 

an example of electric current” (Most school books, and especially the ones for primary 

school students, say that this flow of electrons is called electric current, but in the teaching 

sequence the scientifically correct term was used). 

In the emulator device, when the battery is connected and the switch is on, the LEDs flash 

successively, representing the movement of the electrons flowing in the direction from the 

negative pole of the battery to the positive one. If the battery is connected the other way 

round, the LEDs will spark successively following the opposite direction. The direction of the 

electrons does not affect the illumination of the light bulb, which is therefore shining 

regardless of the direction the free electrons are moving. 


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Children are also taught (in theory) that: “Electric current exists only in closed circuits. 

Therefore, if the switch is off the circuit opens, and although a battery is connected to the 

circuit, there is no forced movement of electrons. Consequently, when the circuit opens the 

electrons move randomly and slowly (i.e. thermally) and the light bulb does not illuminate”. 

In the emulator, in case the switch is open, no mater if the battery is connected to the device 

or not, the LEDs spark randomly, and the light bulb does not illuminate. Incidentally, due to 

the idiomatic use of the everyday language in Greece, the phrase “turn on the lights” 

translates (literally) to “open the lights”, which is of course very close to “open the circuit”, 

only to further confuse the students. The opposite phrase is used for turning the lights off, 

thereby making the distinction between “scientific language” used at school, and “everyday 

language” used at home, final! This is precisely what the teacher tries to avoid as it reinforces 

the widely accepted opinion amongst pupils, namely that science is irrelevant to everyday life. 

There is not much that an experienced teacher can do about it, except to learn to live with the 

problem and try to clear out any confusion in the best possible way. 

After all demonstrations have finished, all students (one pair at a time) experimented with the 

new device. They were asked to try all possible switch and battery combinations and carefully 

observe the results. 

For the AC case an ordinary transformer that provides the circuit with 12V AC is used 

Students learn that “in A.C. current the move of electrons changes from clockwise to counterclockwise, 

and the frequency of the source will determine how many times per second this 

direction of movement changes”. For the purpose of the emulator presented herein, when the 

input of the board detects high frequency alternating current, the frequency is reduced (by the 

embedded software program) so as the eye can see the change in the direction of the flow of 

electrons. The directions of the electrons move changes from clockwise to counter clockwise 

and the students can see clearly the change in the direction of the electron movement. 

Although the alternating current is the type most commonly used everyday, since it is the 

current that electricity-supply companies provide, it is common practice to postpone the 

teaching of it for a while, and to only introduce it after the students had grasped the basic 

concepts of electric circuits, and of DC electric current. The alternating current simulation 

was not taught during the trial teaching sequence presented here, although there is a suitable 

video available online. This was done for several reasons: a) AC current is even more difficult 

for the students to understand, because they cannot distinguish the positive and negative pole 

and normally the electric current direction changes so quickly from clockwise to counter 

clockwise but the light bulb illuminate continuously. And b) AC current was not taught for 

the time being (worried that this way one might encourage students to “experiment at home” 

using power from an ordinary socket). This is because for this demonstration an ordinary 

transformer that lowers the voltage to 12V AC should be used. The students participated in 

the trial were young and not quite aware of the dangers involved when using the 220-Volt 

sockets available at home. They are also unaware of the difference between the current 

available in the sockets and the one provided by the transformer. 

Therefore the teaching of alternating current was postponed for a later time, in order to avoid 

students’ misunderstandings and prevent the acquiring of misconceptions. 

4 The educational trial 

This is the first trial of this new device and, therefore, the knowledge remaining to the 

students when this new teaching procedure incorporating the new emulator device was 


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finished, was compared to the knowledge students had before the teaching. A pre-test was 

given to the students before the trial, in order to identify what they already knew about 

electric circuits and the movement of electrons. All the internationally accepted practices for 

performing research in science education were followed. The questionnaire was carefully 

designed (and was related to the content taught), and effort was paid so as the question to with 

clearly stated and specific questions. This is very important in order to avoid systematic 

errors. 

Children form their first ideas about electric current at a very early age, as electric current is 

an important part of everyday life. Most of these ideas are not scientifically correct. To avoid 

further misconceptions coming from the teacher, it was decided to first test this new device 

together with the new e-learning platform (www.garyfallidou.org) with students of the 4 th 

grade of primary school (10 years old), as formal Physics teaching starts at the 5 th grade of 

primary school. It was decided that, for the educational trial it would be more beneficial to the 

students to work in pairs. This was done in order to allow students communicate and 

cooperate with each other. 

The educational trial is still going on in primary schools that have been randomly selected. In 

this paper only some preliminary results from a group of 19 students will be presented. . 

A few weeks after the activities, the post-test was given to the students to measure the 

remaining knowledge. This took an hour, but it was necessary, as it is the only way to 

evaluate the success of the new teaching approach with the use of the new device. Data 

analysis of the post–tests questions (identical as it happens to those of the pre-test) followed. 

The educational evaluation of the new teaching approach emerges from the comparison 

between the pre and post-tests results. 

4.1. Data analysis 

All relevant statistics were calculated using specially constructed software, interfaced with a 

popular computational and plotting package. The statistical variance was computed and the 

Bessel-corrected standard deviation was calculated for all data points to be presented. The 

systematic error was set at 2.5%. The total error was then computed by adding in quadrature 

our systematic with our statistical errors, these two being independent, by definition. 

The data are presented in double histograms, depicting the percentage of students holding a 

particular idea. The red circles represent the students’ ideas in the pre-test while the blue 

triangles the students’ ideas after the educational trial. The error bars on each point of the 

histogram represent one total standard deviation on either side of the point, as computed for 

this single point. The numerical values of the data are given on the histogram, staggered on 

either side of the points (for the pre-test red circles they are on the left side, whereas on for the 

post-test-blue triangles they are given on the right). 

In some of the questions, students were allowed to offer more than one answer. For that 

reason, it is possible (for some of the questions presented) the sum of the percentages to addup 

to something above 100. 


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4.2. Question 1: In which of the following pictures will the lamp glow? 

120 

Picture 3. 

100 

80 

84,2 

60 

40 

20 

0 

0,0 

22,2 

5,6 

0,0 0,0 

33,3 

10,5 

5,6 

11,1 11,1 

5,3 

0,0 

5,3 

61,1 

47,4 

11,1 

1 2 3 4 5 6 7 8 9 

Picture 4. 

red circles: the pre-test, blue triangles post test 

26,3 

There is not one but three of the above pictures where the lamp will glow; therefore the 

students answer for each of the pictures individually as to if the lamp will shine or not. The 

diagram depicts the percentages of the students that considered each picture as correct. On the 

post-test there is an improvement on the percentage of the students that answered (4) which is 

one of the three correct answers. In the pre-test only 33.3% (±27.5%) of the students 

recognizes the correct answer, while in the post-test the percentage becomes 84.2% (±26.4%). 

In fact this was precisely the circuit that the students had built with their own hands during the 

lesson. It was stressed that in order to make a light bulb illuminate it should be connected with 

the battery at two points a) on the side of the screw and b) under the base. Nevertheless, no 

other successful connections rather than the one depicted in (4) were presented to the 

students, and this seems to indicate with a high level of certainty that this is the reason they 

failed to identify the rest of the connections which would result to the lamp shining. It seems 


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that 9-10 years old children are not able to make the connection linking theory and real life 

situations, as this involves a certain amount of “abstract thinking”. Building the circuit with 

their own hands and the visual representations helps students grasp a higher level of 

understanding, and therefore to associate the rather abstract diagrammatic picture with reallife 

situations. This is in excellent agreement previous findings by other researchers 5 . 

The number of students that chooses picture (8) as correct in the post-test is reduced to 47.4 

(±27.6%) it was 61.1(± 27.7%) in the pre-test, though it seems that this picture confuses the 

students. During the teaching, the students created a simple circuit using plain cables, and 

then another one using light bulb holders. They also used light bulb holders in order to create 

in series and in parallel connections. Although it was stressed, that in a light bulb holder the 

one end touches the screw of the lamp and the other the bottom of the lamp and children were 

asked to observe this carefully it seems that they did not grasp the idea. Besides the teaching 

approach took place within 2 school hours. Therefore the students did not have the chance to 

repeat the experiments (using plain cables with no crocodile clips at the end and no light bulb 

holders) and to re-think what they have done. The last experiments they performed were with 

the use of light bulb holders, and therefore it was not very clear for them where the cables 

were connected. This perhaps is the reason the students were confused. 

Picture (9) also confused the students. Perhaps it is not very clear in this picture (9), which 

was given to the students only in black and white, that one of the cables is not really 

connected to the circuit. 

4.3. Question 2: Which of the following pictures to you believe that represent 

the electron movement during electric current? 

1) 2) 

4) 

3) 

5) 6) 

7) 

Picture 5. 


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90 

80 

70 

60 

50 

40 

30 

20 

10 

0 

11,1 

31,6 

50,0 

42,1 

0,0 

26,3 

22,2 

15,8 

11,1 

5,3 

27,8 

10,5 

5,6 

1 2 3 4 5 6 7 

Picture 6. 

red circles: the pre-test , blue triangles post test 

0,0 

The idea of the movement of electrons is a difficult one for the young students. The electrons 

move following the direction from the negative pole of the battery to the positive one. While 

inside the battery, electrons keep moving from the positive to the negative pole, so as to 

complete the circuit. To make things worse, the so-called “conventional flow” of current is 

the opposite one from the electron-flow. The new device represents the electron-flow in the 

circuit, though children had no visual representation of what is happening inside the battery. 

Since the participants of the educational trial were 9-10 years old, no reference to the 

conventional flow of current was made in order to avoid a major misconception. 

In the post-test the students’ answers are divided between (a) 31.6% (±27.3%) (b) 42.1% 

(±27.6%) and (c) 26.3% (±27.1%). Taking into account that the educational trial lasted 2 

hours, the results are encouraging, most children understood that electric current flows 

following a circle, in the whole circuit, but it is not as good as we would have liked. 

4.4. Question 3: Which of the following pictures (referring to the amount of 

electric current in the wire) do you consider as correct? 

same 

same 

less 

more 

1) 

2) 


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3) 

in this part only 

4) 

in this part only 

Picture 7. 

120 

100 

80 

83,3 

60 

68,4 

40 

20 

0 

11,1 

5,6 

10,5 10,5 10,5 

0,0 

1 2 3 4 

Picture 8. 

red circles: the pre-test, blue triangles post test 

We should clarify here that the numbers correspond to the students that consider each 

individual picture as correct. Research in science education indicates that, before teaching 

takes place, most children believe that in a circuit electric current exists only in one of the 

cables. This is once more proven correct, in that during the pre-test 83.3% (±26.6%) of the 

students considered picture (4) to be correct. 

During the teaching, each group of students connected ammeters before and after the light 

bulb and observed the indication. Emphasis was paid to the fact that the indication on both of 

them was the same. 

It seems that after the teaching, students had a clearer view about the movement of the 

electrons and 68.4% (±27.3%) gave the correct answer. 

5 Discussion and conclusions 

During the teaching approach, children watched a video (from the on-line material) on the 

electronic-whiteboard touch-screen used for showing the video depicting the experiment they 

were asked to perform, and subsequently to select whatever equipment they needed to 

perform the experiment, from a table where all such the material and apparati was exhibited. 

Children faced no difficulties on that. Two interesting observations were made when children 

were asked to make more light bulbs illuminate simultaneously: a) most children chose and 


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did succeed to give the in-parallel (as opposed to in-line) connection and b) When children 

work individually (as it was done in a previous trial of the on-line material) they collected 

from the table with the materials some cables and light bulb holders, but none asked for a 

second battery, while when working in pairs, they all collected cables, light bulb holder and 

an additional battery. Children in Greece are not used to work in pairs. Perhaps when they 

were asked to make a second light bulb illuminate, they interpreted the task as “the other child 

should make his/her own circuit”. Consequently, when children worked in pairs, the 

researcher had to withdraw the extra batteries from their tables and re-pose the question. 

Another interesting result is that most of the children faced difficulties when they were asked 

to create in-series (as opposed to parallel) connections in the lab. Students faced difficulties 

even after they had seen the relevant video. Many of them faced problems even after a long 

analysis on how they should do it. 

Time was needed in order to explain to the students what the electrons are. Perhaps a new 

educational device (or a computer-based learning environment) simulating the nuclei and the 

electrons, and the way they are connected with each other in order to create atoms, would be 

very helpful. 

Although students were unfamiliar with the research method, they expressed no objections to 

filing-in the pre-test and the post-test, which is a surprising result in itself. Students asked 

details about the device, and they wanted to see the back of it, trying to understand how it 

works. 

As far as the new device is concerned, children faced no difficulties in using it. Students 

responded quite well to the new teaching approach with the use of the new device. They were 

truly enthusiastic, and pleased by their experience. They found the new teaching approach and 

the use of the new device interesting, and would like to see other scientific topics been taught 

using similar approaches. 

Despite the fact that (macroscopically) the present research can only be considered as 

preliminary, it would seem to indicate, nevertheless, that it helps students’ ideas move 

towards the scientifically correct ones. 

Nevertheless, more research is surely needed using this new teaching approach aided by the 

new device testing students of various ages, and from various geographical areas. 

Rererences: 

[1] Niedderer H., and Goldberg F., Learning pathway and knowledge construction in electric circuits, 

Paper presented at “European Conference on Research in Science Education” University of Leeds, 

(1995) 

[2] Shipstone D., Pupils‘ understanding of simple, electrical circuit, Physics Education, 23, (1988) 

[3] Garyfallidou D. M., “A novel computer based environment designed to teach electric circuits”, 

International Conference ICL 2009 the challenges of Life Long Learning, in Auer M ed., Kassel 

University Press, ISBN 987-3-89958-481-3, total pages 9 

[4] Ioannidis G. S. and Garyfallidou D. M., Education using information and communication technology 

(ICT), and ICT education: categories methods and trends, In: Auer M. and Auer U. (Eds.) Proc. 

ICL2001 workshop: “Interactive Computer aided Learning, Experiences and visions”, Villach, Austria, 

Kassel University Press, (2001) ISBN 3-933146-67-4 


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[5] Tsihouridis Ch. et al. Evaluation of educational software regarding its suitability to assist the 

laboratory teaching of electrical circuits) in Auer M (Ed) International Conference ICL2007 ePortfolio 

and Quality in e-learning, 2007 Κassel University Press ISBN 978-3-89958-279-6, total pages 15. 

Author 

Despina M. Garyfallidou, Ph.D. 

University of Patras, 

School of Education, 

The Science Laboratory, 

26500, Rion, Greece 

e-mail: d.m.garyfallidou@upatras.gr 

d.m.garyfallidou@gmail.com 


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Microcontrollers in Physics education: a circuit simulation ... - ICL

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