Do you think that the printer is displaying messages, when it is connecting with computer? Well, how about you break the rules and create a standalone LaserJet printer that can display custom messages without a computer?

It might sound a little bit nonsense, but you can really make it here! In this case, you’re going to use the HP LaserJet printer, where it has a little display and you can use PJL (Controlling language) to change everything that being displayed on it!

First of all, you need to use the Centronics parallel port, as it’s easier to be implemented than others. For the microcontroller, an ATTiny2313 will be the best part to send signals through a parallel port.

You can connect the AVR directly to a Centronics-connector, where it can be mated with the socket on the LaserJet. By the way, a capacitor is needed in this project to filter the power supply.

You just soldered all the Centronics-connector, an AVR, a 20-pin IC socket and a capacitor together to a nice and compact unit. After it, you’re done and can start testing out the result…

Note: This project is very cheap and easy to install, and it can be disposable as well!

Are you familiar with the single sided circuit boards? For those that didn’t know what this all about, then you should stick your eyes on this article.

For your information, the most common type is a circuit board that only has printed wiring on one side and all the components are on the other side. A permanent solution to the single-sided circuit board is having it in the shape of a Mobius strip.

The Mobius strip is a surface with only one side, thus it has only one boundary component. The Mobius strip has the mathematical property of being non-orientable. As a result, a model can easily be created by taking a paper strip and giving it a half-twist, and joining the ends of the strips together to form a loop.

Beside that, the ATtiny2313 that has 20-pin device and 17 available output pins, will be used as the main heart in this single-sided circuit board.

To be honest, this project is pretty simple and straightforward, where it only requires you drawing the conductive silver ink throughout the Mobius strip. After that, you’re done with it and can enjoy the using it without any further modification.

Probably everyone knows the game of life where area is divided in to cells where each cell in the grid has 8 neighbour cells. By using simple set of rules these cells become alive – they can spawn, modify themselves, do logical operations and even create Turing machines.

The interesting thing on this particular project is that game “Life” is displayed on 4×20 character LCD. LCD is controlled by AVR ATTiny2313 microcontrollr which actually interfaces the LCD and has on boredom button. Interesting fact that character LCD is used as graphical by defining special characters. Project is programmed in C language and compiled with WinAVR compiler tools. Project files are available for download here.

This is cool project to pay attention to. It can be used for PC modding or elsewhere where scrolling text effects are needed. Display is built of 50×7 LEDs that is controlled by AVR AT90S2313 microcontroller (may be substituted by ATtiny2313).

Text can be sent from computer via RS232 port or displayed from external EEPROM 2k memory where 768 characters can be stored. Fonts set of 256 different characters can also be programmed and mast be written to EEPROM before sending text to display. Hardware project with 3mm LEDs can be downloaded here. And latest firmware here. There might be minor changes are needed to adapt to newer WinAVR and ATtiny2313 microcontroller.

This stepper motor driver can control two independent steppers via RS232 interface. Control commands can be sent by using simple terminal program like HyperTerminal. Circuit is capable to drive two unipolar stepper motors operating in full step mode. Motors can be powered from 24V and consume up to 0.5A of current.

ATtiny2313 microcontroller sends control pulses via ULN2803A chip, which can drive up to 500mA. Firmware is developed by using BASCOM AVR software. Or you can just download hex file which is ready to flash to microcontroller. This might be useful device for testing stepper motors.