Circuits

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Adapter to connect a PS/2 mouse to a serial port

 ps/2 to serial

If you still have an old computer, the problem is to connect to it modern mouse may be familiar to you. Old mechanical mouse, sooner or later come into disrepair - cable wear, buttons do not work, etc. In general, modern laser mouse is usually much nicer than the devices of the last century

Because the serial mouses are no longer produced, then the for PC without a PS/2 port is still two options: adapt the PS/2 or USB mouse. With PS/2 mouse everything is much easier - this protocol can be implemented in almost any microcontroller, such as ATMega8.

The adapter is built on ATMega8 microcontroller and uses MAX232 to match the TTL signal levels with a serial port levels. The microcontroller receives data from the PS/2 mouse and transmits them via the UART.

Tape player and recorder for Sinclair ZX Spectrum on Atmega128

Магнитофон для zx spectrum на atmega

ZX Spectrum - a computer designed over 30 years ago with a 3.5 MHz processor and only 48 KB of RAM. For him, it developed a huge number of software and games. Moreover, new game releases are constantly in our days.

Previously, the program is loaded from the tape. And the loading is not always succeeds, sometimes the game had to try several times to load often getting message "R Tape loading error".

Alternatively audiotapes today suggests a memory card that stores the program files in the formats TAP, WAV and TZX. And as an alternative to tape recorder - microcontroller device that can play and store these files.

Two microcontroller regulators for fans

Two microcontroller regulators for fans

This device allows to reduce the noise from cooling fan. It turn off the fan or reduces the rotation speed depending on the temperature of the radiator. Also the device beeps when temperature exceeds a threshold. There are two variants of device for fans of different power.

The first variant is designed to control 12-volt computer fan, and has been fully implemented on the SMD-elements:

Mood Lamp on ATTiny13

Moodlamp on ATTINY13

Mood lamp is a LED RGB lamp that changes the color of light at random. There are a lot of mood lamps projects in the Internet and usually they use relatively "big" microcontrollers. I wanted to make a lamp based on simply ATTiny13 microcontroller.

The circuit of the device is very primitive and shown in the figure below:

Christmas Icicle

Christmas led icicle on microcontroller

This LED "icicle" made from mainly blue LEDs. This device can serve as Christmas present or New Year's ornament. The "icicle" can be transformed into a "candle" if to use red and yellow LEDs and to change accordingly its external design. As the body I used two fur-tree toys: transparent plastic icicle and one-half of the Christmas ball. LEDs are placed in the first and second placed the microcontroller board.

The Christmas LED-Snowflate-thermometer

Новогодняя светодиодная снежинка с микроконтроллерным управлением и индикацией температуры

This LED "Snowflate" made from mainly blue and white LEDs and can serve as Christmas present, Christmas ornament or night light. The device also has a thermometer. Snowflake has 6 beams and every beam contains 8 superbright LEDs. I have used blue and white LEDs with different diameters.

Doorbell with I2C-flash

Dorbell

It's a simple doorbell that can play melodies and audiorecords from I2C flash-memory chip. The device has two parts - digital and analog. The digital part used the microcontroller AT89C2051 and flash-memory AT24C256.

Solderless breadboard - microcontroller designer

Solderless breadboard - microcontroller designer

This breadboard can be used for temporary prototypes and experimenting with circuit design more easily. It is designed for prototyping circuits on chips in DIP-packages and discrete components. The breadboard is intended primarily for prototyping devices on microcontrollers AVR (ATMega8/48/88/168/16/32/8535/...) and АТ89Сх50. The breadboard is based on 40-pin single row connectors PBS (step 2.54mm) and IC-sockets.

LED activity level indicator for PC

LED activity level indicator for PC

This device is based on AT89C2051 microcontroller and allows to display HDD and network usage.

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