Who couldn't use a little more screen space?

Text LCD’s are handy for any occasion, a printer port on your PC is also darn handy as well. Mix together and add in a splash of linux and you get a very handy Linux device driver for a 16×2 LCD connected to the parallel port.

Electrically the LCD is wired up in a typical 4 bit mode, this allows the parallel port to use its 8 bit data register to write data, but also control the Register Select and Enable pins. Next is to make a module for linux to use, it seems like pretty standard fair for this type of screen.

Make the driver, insert the module so it can be loaded, and add a node so you know where to find it later, and your only an “echo Hello > /dev/my_lcd” away from finding all sorts of creative uses for your new external display.

Build your own 4-channel logic analyzer

If you’re just getting into hobby electronics chances are there are lots of tools you’d like to get you hands on but can’t yet justify the purchases. Why not build some of the simpler ones? Here’s a great example of a 4-channel logic analyzer that can be your next project and will add to your arsenal for future endeavors.

As you can see, [Vassilis’] creation uses a cellphone-sized LCD screen as the output. It is powered by four rechargeable batteries and driven by an ATmega8 microcontroller. He’s designed the tool without power regulation, relying on the ATmega’s rather wide range of operating voltages, and a few diodes to step down that voltage for the LCD screen.

As you can see in the clip after the break, alligator leads can be used to connect the test circuit to the inputs (don’t forget the ground reference!). Thee buttons at the bottom let you navigate the captured data by panning and zooming. Perhaps the best design feature is the single-sided circuit board which should be quite easy to reproduce at home.

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