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Embedded Systems Class 2007

Embedded systems class is very challenging class, at least for us and the teacher. Electronics and programming skills of incoming SpaceMasters vary a lot from beginners to advanced professionals. Our Embedded systems class is designed for beginners to provide basic skills for building and programming small electronic devices. We try to find out also some challenging tasks for more experienced students, although other SpaceMasters and the teacher value a lot the help that experienced students may give for the beginners. Also this year more experienced students helped the beginners to get things done. As a result we may present several innovative devices that the SpaceMasters built.

Ambient light with a power LED

Ambient light is a small embedded system to adjust the light emitted by a Power-LED. The microcontroller involved is manipulated either directly by switches or by a PC via serial communication. Wedeveloped an application software that compiles a slide show of photographs. During the show, we dim the ambient light created by the Power-LED in accordance with the picture shown in that moment. The photographs by Matthias Elsdörfer.

Self balancing robot

The robots balances itself and stays in upright position on its two wheels.By its structure this robot is not statically balanced and it has to move fourth and back to maintain stability. Robot senses the angle respect to ground by alow friction potentiometer attached with small rod.

This robot is been made from off-the-shelf part except STK500 board which we used as a given in this subject. Apart from STK500 board all you need is one potentiometer and H-bridge drive circuit, potentiometer can be found in every electronics laboratory room and for H-bridge drive I would recommend the L9904 since the application circuit is included on the datasheet,or the classic L298 is also fine. For motor we use 12 volts dc automotive motor from BOSCH.

Finnish Vocabulary Helper

Figure shows the simple LCD display with push-button interface device . The processor used is AVR’s ATmega88. The user interface contains three push-buttons - namely ‘Shuffle’, ‘Explain’ and ‘Next’. The Finnish words and its meaning – if requested - are displayed on the LCD display. There are also supplement components such as jumpers to enable LCD backlit and to reset the device, LEDs to indicate power input and give generic feedback.

When the device is turned on, it shows a random Finnish word. If the user knows the word, he can proceed by either pressing the ‘Shuffle’ button to jump to another word or pressing the ‘Next’ button to continue with the next word on the vocabulary list. If the user doesn’t know that word, he can press ‘Explain’ button to see the meaning in English. The words are stored directly in the processor flash memory. Further improvement would be implement external EEPROM memory for larger word list, also battery for portable feature.

Demonstration of Persistence of Vision with LED-Array

LED-POV (Persistence of Vision) display utilizes 1-D LED array scanning in 2-D either in circular or in linear motion. It takes advantage of persistence of vision of human eyes, which makes it possible to perceive the scanning array as a 2-D display. This technique is often used for entertainment in daily life such as toys and clocks. We used an accelerometer just for a trigger of starting blinking the LEDs. After it detects a strong acceleration meaning the array changes its direction of linear back-and-forth motion, it starts blinking LEDs controlled only with time afterwards.