[291] | 1 | <?php |
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| 2 | $seiten_id = 'lernprojekte'; |
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| 3 | $version = '$Id'; |
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| 4 | $titel = 'Study projects'; |
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| 5 | |
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| 6 | require '../lib/technikum29.php'; |
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| 7 | ?> |
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| 8 | |
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| 9 | <h2>Study projects</h2> |
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| 10 | |
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| 11 | <h3 id="Q1"> technikum29 supports school projects</h3> |
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| 12 | |
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| 13 | <p>Microcontrollers revolutionize |
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| 14 | and influence next to everything. How can schools participate on these |
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| 15 | developments and perform successful and interesting projects?<br> |
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| 16 | Six pupils of Q1 (12th year in school) of the Albert-Einstein secondary |
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| 17 | school were looking for a suitable idea for their so called "project |
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| 18 | week". This project should be connected to mathematics, physics and/or |
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| 19 | computer science. This is where the technikum29 got involved. The idea |
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| 20 | the pupils came up with was to connect technology from the 1950s with |
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| 21 | modern equipment of 2012. Communication spanning time and technology.<br> |
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| 22 | <div class="box left"> |
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| 23 | <img src="/shared/photos/kommunikationstechnik/arduino1.jpg" width="606" height="335" /> |
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| 24 | </div> |
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| 25 | <p>Traditionally such projects required knowledge only accessible to |
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| 26 | computer scientists, engineers and the like. Often they had to spend |
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| 27 | weeks of reading data sheets, writing cryptic assembly code etc. How |
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| 28 | things have changed! Since 2009 a cheap and versatile module named |
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| 29 | "Arduino" is available - a controller based on the well known ATmega |
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| 30 | 328 chip featuring 32 kB of memory. Arduino boards are designed not |
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| 31 | for the expert but for the layman and are the perfect base for |
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| 32 | creative people, artists, designers etc. |
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| 33 | <br> |
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| 34 | This project focuses on connecting computers to the "real world". The |
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| 35 | small Arduino board can be programmed to be used as an interface for |
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| 36 | nearly everything. The pupils decided to connect an early fax machine |
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| 37 | (a Siemens KF108 made in 1958) to a modern PC. <br> |
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| 38 | This fax machine is based on a rotating drum which holds the sheet of |
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| 39 | paper to be transmitted to the receiving station. The picture is |
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| 40 | scanned in a spiral movement by a photodetector that slowly moves in |
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| 41 | parallel to the axis of the drum. Of course, this is incompatible with |
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| 42 | more recent fax machines. |
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| 43 | |
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| 44 | The Arduino was planned to act as the interface between this historic |
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| 45 | device and a modern PC. Thus the pupils first had to learn how to |
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| 46 | program such a micro controller which turned out to be quite difficult |
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| 47 | for non-programmers. Nevertheless the software approach has its |
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| 48 | advantages: It is more easily debugged compared with a traditional |
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| 49 | hardware based interface. Thus it only took a single week to program |
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| 50 | and interface the Arduino board to the Siemens fax. |
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| 51 | |
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| 52 | <div class="box left"> |
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| 53 | <img src="/shared/photos/kommunikationstechnik/arduino2.jpg" width="606" height="354" /> |
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| 54 | </div> |
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| 55 | |
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| 56 | <p>The fax machine generates an auido signal with a frequency of 1.5 kHz |
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| 57 | denoting black pixels to be transmitted. To convert this into a binary |
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| 58 | signal with a 5V level an amplifier circuit is needed that is followed |
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| 59 | by an RC-combination. In addition to that a synchronization signal is |
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| 60 | necessary to signal the start of a new line being scanned. This is |
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| 61 | generated utilizing a reed-contact that is triggered by a so called |
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| 62 | "super magnet" that has been glued onto the axis of the scanner drum. |
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| 63 | The reed-contact thus generates a signal for every revolution of the |
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| 64 | drum which corresponds to a single line being scanned.<br> |
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| 65 | |
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[295] | 66 | The control program for the Arduino was developed by the pupils (and is |
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| 67 | <a href="/de/lernprojekte/arduino-projekt-programme/" class="go">online avaliable |
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| 68 | in our repository</a>). It allows the picture being scanned, a historic Mickey-Mouse drawing, to be transferred to the PC |
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[291] | 69 | where it is displayed slowly line by line with good resolution. |
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| 70 | |
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| 71 | The experiment was a full success and will inspire future projects. |
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| 72 | |
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| 73 | <p class="small">*) Arduino: The name of this board derives from King "Arduino of |
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| 74 | Ivrea" who lived in medieval times in northern Italy where the |
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| 75 | controller was developed.</small> <br> |
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| 76 | |
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[326] | 77 | <h3>Siemens computer for demonstration</h3> |
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| 78 | |
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| 79 | <div class="box center"> |
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| 80 | <img src="/shared/photos/rechnertechnik/siemens-democomputer.jpg" alt="Siemens-Democomputer" width="700" height="587" class="nomargin-bottom" /> |
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| 81 | <p class="center"><b>Siemens computer</b></p> |
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| 82 | </div> |
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| 83 | |
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| 84 | <p>The demonstration model shown above was built in 1973 by Siemens (Germany). It |
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| 85 | was used as an educational tool for technicians and engineers. The large |
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| 86 | machine on the right was built in rather high numbers for computer science |
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| 87 | courses and the like. Even today it can be used to show the basic principles of |
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| 88 | instruction processing, internal cycles etc. Its short word length of only 4 |
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| 89 | bits is sufficient for this.<br> |
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| 90 | The program can be setup on the left by use of plugs containing various binary |
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| 91 | values representing the instructions of the machine. The "computer" can be |
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| 92 | operated in either one of two modes: cycle mode or instruction mode. In |
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| 93 | addition to that its clock cycle time can be set arbitrarily or single step |
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| 94 | mode can be selected. 126 incandescent lights show the data flow through the |
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| 95 | registers, the operation of the control circuitry, the arithmetic/logic unit |
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| 96 | and the memory locations.<br><br> |
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| 97 | |
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| 98 | The demonstration model represents a bit-parallel program controller computer. |
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| 99 | The currently implemented program adds to binary values. It demonstrates that |
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| 100 | even short word lengths do not necessarily restrict the range of values that |
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| 101 | can be processed by such a machine.<br> |
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| 102 | |
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| 103 | |
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| 104 | |
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| 105 | It is a truly wonderful machine that displays the elementary processes taking |
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| 106 | place in every computer even today.</p> |
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| 107 | |
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[291] | 108 | |
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