note : no picture for the project, i just replace it with analog PS 1 joystickDownload :
The Magstripe (Track 2) Reader project can be used to view numerics stored a magnetic data card. Although there is no writeback ability, the device is very useful as a card debugger. The treatise will use an LCD character display to relay this data to the user. The circuit uses an AVR microcontroller and can modified to work with similar RISC controllers.Although the card reader can't write back to magnetic card, I guess this is a one of good reference to learn how card reader work. For download the reference clik here (zip file)or visit this link
When you need connect your Microcontroller Project to COM port in PC you need RS 232 converter. There are many chip to solve the problem like MAX232, DS275 etc. But if you need simple and chep for RS 232 converter, i though this circuit will be usefull for you. The design made by Wichit Sirichote.
"A circuit diagram shown above was used two small signal transistor, NPN and PNP transistors. Dash line separate transmitter and receiver circuit. For those who need only transmitter circuit can use above circuit (and GND (5) signal ). Technically the RS232C is -3V to -12V for logic '1' and +3V to +12V for logic '0'. The transmitter circuit uses PNP transistor, BC557. While in mark state the TxD signal is logic '1', Q1 turns off. TxD (pin3) then provides -9V (depends on what converter chip being used for COM1, say) to RxD (pin2). For space state, TxD control signal then becomes logic '0', which turns on Q1, the approx. +5V is then fed to RxD (pin2). With this method, while sending data has being made, TxD (pin3) must stable at -9V, say"There also some modification from above circuit. For more detail you can download here.
Evil Mad Scientists have create cool and simple Darkness Sensing LED ever. It's only need few component: a CR2032 lithium coin cell (3 V). LED, an LTR-4206E phototransistor, a 2N3904 transistor, and a 1 k resistor. You can choose it for your first project during learning electronic.
"When light falls on the phototransistor, it begins to conduct up to about 1.5 mA, which pulls down the voltage at the lower side of the resistor by 1.5 V, turning off the transistor, which turns off the LED. When it’s dark, the transistor is able to conduct about 15 mA through the LED. So, the circuit uses only about 1/10 as much current while the LED is off. One thing to note about this circuit: We’re using a red LED. That’s because the voltage drop across the transistor allows less than the full 3 V across the LED. The full three volts is really only marginal for driving blue LEDs anyway, so two-point-something really doesn’t cut it."[link]
There also some modification from above circuit. For more detail you can download here.
"A circuit diagram shown above was used two small signal transistor, NPN and PNP transistors. Dash line separate transmitter and receiver circuit. For those who need only transmitter circuit can use above circuit (and GND (5) signal ). Technically the RS232C is -3V to -12V for logic '1' and +3V to +12V for logic '0'. The transmitter circuit uses PNP transistor, BC557. While in mark state the TxD signal is logic '1', Q1 turns off. TxD (pin3) then provides -9V (depends on what converter chip being used for COM1, say) to RxD (pin2). For space state, TxD control signal then becomes logic '0', which turns on Q1, the approx. +5V is then fed to RxD (pin2). With this method, while sending data has being made, TxD (pin3) must stable at -9V, say"
The goal of this project was to build a LED-based device running on a microcontroller chip to mimic how fireflies might theoretically synchronize their flashing in nature. The device serves as a future model on how to implement a physical form of networking using a microcontroller chip.
This circuit designed by Antonis Pontikakis. It's used ATmega32 microcontroller as the main part. At the circuit, there are 2 24LC32 eeprom memories, the 1st for internal standard melodies and the 2nd one is for user's compositions.
Stimmmopped is AVR ATmega8-based project that will assists you in tuning your string instrument to a given tone. It utilizes the stroboscopic effect to give feedback about the adjustment of your instrument. When the frequency that you chose has tone then the two LEDs on the board blink. Two lines are projected at a fixed position on the string when the string vibrates with the correct frequency. If frequencies don't match, the lines appear to be blinking or moving to the observer's eye. The moving or blinking effect decreases with decreasing difference between the two frequencies.
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The project allow you streaming your radio broadcast wirelessly over internet. The wifi radio built using an Asus WL-520gu wireless router, an old USB audio headset, AVR ATmega8 and other part. If you are interested to build Wireless Streaming Radio, here is the requirement you need to prepare : Wireless connectivity through existing Wifi network; Audio output (preferably 44kHz, 16 bit stereo); Shoutcast/MP3 streaming audio decode; A display to indicate the station and currently playing song; An integrated amplifier and speaker(s); Several built in station presets; and Simple user interface, using standard radio controls (volume, tune, etc).
The Lego Mindstorms NXT has been in the market since 2006 and its potential for robotics application is increasing throughout the years. The Lego Mindstorms NXT educational kit consists of several types of sensors and motors, allowing the robot to be programmed to respond autonomously to different types of situations.
This project uses a stepper motor to control the position of solar energy collectors, using Intel 8085 Microp . The software includes the positioning of collectors through stepper motor & data acquisition and processing in Microprocessor.
