Easy To Build Z80 Single Board Computer

August 16, 2011 by Brian Benchoff 27 Comments

[Alexis] sent in a single board computer he’s been working on. The project goal of his build was making it easily reproducible. From looking at the schematics, it’s one of the simplest fully-functional computers we’ve seen. The build runs CP/M 2.2 off of two 3.5 inch floppies. This opens up a lot of options as to what software is already available. Although it operates over a serial terminal, [Alexis] pretty much duplicated an Osborne I, only at double the speed.

[Alexis] got a little e-fame from his earlier 8088 homebrew computer built from very early 8088’s rescued from an electronics junk shop. These 8088 computers made the blog rounds by playing Still Alive with a SID chip from a Commodore 64 and a YM2151 FM synth chip.

For now, I guess we’ll have to settle for a video of [Alexis]’ Z80 computer running CP/M. Check out a video after the break of his computer running the greatest Infocom adventure, Hitchhiker’s Guide to the Galaxy.

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Playing SNES With An R/C Controller

August 14, 2011 by Brian Benchoff 5 Comments

Normally when we see an R/C transmitter used in a build we’re prepared for robots, quadcopters, or UAVs. [Alex] found a new use for his Futaba radio – hooking it up to his Super Nintendo.

We’ve seen a lot of builds using game controllers as interfaces to other hardware. The N64 media remote comes to mind, as does the NES iPod dock. Outside of a few builds to automatically win in-game currency for you, we haven’t seen much of anything to control a video game with additional electronics. [Alex]’s build happily bucks that trend, and technically gives the SNES an analog controller.

The build uses an mBed microcontroller to capture the radio’s button and stick positions. This is sent through a two shift registers to produce the 16-bit packet required of the SNES controller protocol. [Alex] posted all the software for his build, and from the looks of it the code seems pretty portable. [Alex] says he’s working on getting his Sega Saturn running with his Futaba, so we can’t wait to see some Panzer Dragoon action. Check out [Alex] demoing his controller with Gradius III after the break.

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Overhaul An Old Mechanical Keyboard

August 12, 2011 by Jesse Congdon 16 Comments

Deskthority forum user [lowpoly] recently posted a writeup on his complete overhaul of an Apple M0110 mechanical keyboard. Any one familiar with the satisfying clack of a good mechanical key under their fingers can appreciate the effort put into this project.

[lowpoly] removed the keyboard’s PCB, rewired the key matrix adding diodes, built in a teensy USB board, broke apart the mechanical switches and fit replacement springs and finally applied a generous portion of retr0bright to all of the aging plastic. Since the teensy has no mounting holes [lowpoly] had to create a mounting assembly out of some spare plastic. A usb mini cable is even fitted into the original RJ-11 connector. To compensate for the lack of PCB the key assembly was fitting with some rubber washers. To top off the whole thing some nice new rubber feet were taped to the underside of the M0110.

[lowpoly] reports that with the foam, new springs, and lack of PCB the keyboard is much quieter and easy to use. The end result is a slick retro looking modern keyboard. If you’ll excuse us we have to go rooting through some old storage bins to find our own ancient keyboards.

We have seen our share of vintage keyboard hacks which can be useful, impressive and sometimes just odd. This build keeps it down to a nice simple, functional, useful retrofit. Nice work!

Add A Real Life Hardware Terminal To That Newfangled Computer Of Yours

August 11, 2011 by Mike Nathan 77 Comments

vt200_serial_hardware_terminal_over_usb

If you find a crusty old IT guy and give him half a chance, he’ll probably regale you with stories of how things were done “in the old days” where no one had their own computer and everyone worked on mainframe-connected dumb terminals. [JSTN] yearned for a true to life terminal display that he could attach to his 2010 Mac Pro, and since there’s no chance anybody is bringing one to market any time soon, he pieced one together on his own.

He dug up a digital VT220 terminal, and got to work trying to interface this office relic with his shiny new Mac. He found a few helpful tips from someone

God’s Own Keyboard, Now With Bluetooth

August 9, 2011 by Brian Benchoff 49 Comments

For decades a thunderous roar rose from the bowels of IBM keyboards like the animus of angry and forgotten gods. These keyboards have fallen silent of late, due only to incompatibility with newer hardware. Now, Model Ms have been given a reprieve from landfills or recycling centers because of the work of [wulax] of geekhack and his Model M Bluetooth controller board.

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Old Pachinko Game Tweaked To Add A Reward System

August 8, 2011 by Mike Nathan 5 Comments

restored_gumball_vending_pachinko_machine

[Tim Higgins] picked up an old pachinko game at a garage sale for his wife, but it ended up sitting unused in the garage for a few years. When he finally dusted it off, he decided that he wanted to restore and build a nice cabinet for it, though he thought the idea was a bit lame.

He says he likes to use some sort of CPU in his projects, and even though it was overkill, he made it his goal to add some sort of microprocessor to the game. He didn’t want to ruin the original aesthetics of the machine, so he decided that he could use an Arduino to drive a rewards system for skilled pachinko players.

Using some PVC pipe, he built a treat hopper which is controlled by the Arduino. When the player wins, the microcontroller triggers a small hobby servo, which dispenses gumballs/candy/etc.

[Tim] says that his wife loved the gift, and he was quite pleased with how it came out as well. Hit up his blog for additional build details and be sure to check out the photo slideshow of the restoration that we have embedded below.

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Quick And Easy Audio Preamp

August 6, 2011 by Mike Nathan 16 Comments

npn_transistor_audio_preamp

The most recent installment of [Dino Segovis’] Hack a Week covers the construction of a simple NPN transistor audio preamp. Some time ago, he built a small audio amplifier using an LM386 which worked well, but didn’t quite get his music as loud as he would like it. He decided to build a preamp to complement his amplifier, and demonstrates how you too can build one with just a small handful of components.

As the name probably suggests, the cornerstone of this amplifier is an NPN transistor. He explains that a forward bias is applied to the base-emitter junction, which results in the transistor operating halfway between its cut-off and saturation regions. Both halves of the input audio signal are superimposed on this bias voltage, resulting in a decent amount of gain across both channels from a relatively small package.

The preamp isn’t going to win any awards among audiophiles, but it is definitely a great beginner project. Its a novel way of demonstrating how transistors work, while producing a useful takeaway piece of audio equipment at the same time.

Continue reading to see a video showing just how big an effect [Dino’s] NPN preamp had on his music.

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