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Published on: October 15, 2013 / Comments: None

The DECbox is a beautiful DEC VT100 terminal running from a beagle bone

When you think of emulators, you probably think of old video game emulators.  Well think further back to a text based gaming society like Zork.  Before GUI’s were established most computing was done via serial terminals.  And this project pays homage to that time.  The DECbox emulates a variety of vintage terminals, wrapped in a sexy vintage enclosure.

The brains of the DECbox runs off of a beagle bone with a special cape to break out all of the UARTs the processor has into serial ports.  On the software side its running multiple versions of SimH from the The Computer History Simulation Project.

If you are into retro computing, this is a really awesome project.  Collecting numerous vintage terminals can take up a lot of space, and a lot of that old hardware is broken now.  It’s great to see the project rebirth the feel of the vintage terminal for history preservation.

DECbox project link here, more info about the software install here.

Published on: September 17, 2013 / Comments: None

Build an Op-amp based RIAA phono preamp

Believe it or not some people are still in to vinyl, actually I think more people are getting into vinyl nowadays!  One thing you might not have on that fancy turbo pandora playing surround sound is a phono input for that crusty record player of yours.  Why not build a preamp so you can hook it up?

The build is based on an OPA2134 op-amp and uses a bipolar +12/-12 power supply.  Since this type of amplifier is high gain it is important to make good design decisions to reduce noise.   First off you should have an earth ground, and a fully shielded metal enclosure or else you might be picking up a lot of unwanted noise.  Second the power components should have ample space away from the audio components.  The rest can be handled with some resistors and caps.

Nice build.  Schematic included, check out the project on diyaudioprojects.

Published on: September 10, 2013 / Comments: 1

Amazing Nintendo Nixie clock sporting retropie

Bradley does some amazing work. Usually it’s in the form of replica light sabers and what not. This time he was commissioned to a NES inspired nixie clock for a wedding gift, but decided why stop there ? Let’s make it an actual playable NES.

Inside on the clock side is an Arduino Uno with a ArduiNIX Nixie Tube Driver shield + Nixie tubes. On the gaming side is your usually Raspberry Pi running Retropie distro. Controllers are NES style usb controllers, and a RGB led provides mood setting. This is all wrapped in a lovely custom wood enclosure painted to look like a real NES. He’s even put real NES start / reset buttons in there.

Man that’s a site to make anyone envious! More pictures and info can be found on Bradley’s site.

Published on: September 5, 2013 / Comments: 2

Build your own wireless modem using a 555 timer and 565 PLL

This build uses good old FSK (frequency shift keyring) technology sending 1′s and 0′s through the air.  Although its applied using infra-red, the same concept is used for RF.  Also Infra-red is still technically wireless (lol).  So on to the build.  Just in-case you want to brush up on your FSK I recommend just straight up hitting wikipedia.   (If not, here’s the TLDR version;  A steady pulse is used to represent a 1, and a variation in the pulse width is used to represent a 0)

On the transmitter side a 555 timer is set up as a Astable Multivibrator, the digital input (fed from say a microcontroller) pulls down the transistor which modifies the frequency of the 555 timer, causing a 0.  Leaving the pin high (representing a 1)  leaves the 555 timer alone.  The data is transmitted via infra-red led.

On the receiver side, a 565 PLL (Phase Lock Loop) IC locks on to the frequency of the 555 timer and outputs a 1 or a 0 when the signal alternates between the 2 frequencies.

This is a great project but mostly as an educational one.  Full post up on gadgetronicx.

Published on: August 22, 2013 / Comments: None

Upgrade your Commodore 64 with S-video

While I’m having a retro commodore 64 flashback day, I came across this really sweet mod for adding S-video to your C64.  Arto has a great write-up on doing this.  He’s got a schematic on building the circuit, it looks like you should have most of the parts already in your parts bin.

The article suggests disconnecting the RF sub-circuit which–while I think is probably a smart move if you are looking for the best video quality–is going to be a deal breaker for some people who don’t want to make any permanent modifications to their board.  I say do it!

Published on: August 22, 2013 / Comments: 1

A few tips for getting (or re-getting) into Commodore 64

If you used to own a commodore 64 back in the day, or you’re a new-school hipster enthusiast into retro computing… you’re going to need some help getting started.  First thing you’re going to need to do is get a decent working unit.  Here’s some tips on what to look for.  According to the article, the item you want to look at is the power supply.  And while disk drive’s are cool to look at, let’s get real and replace it with a SD card adapter.

In part two of the getting started guide, we’re trying to go quasi-modern with our commie right?  So let’s get a fast load cartridge. There’s also some commands to get you going.  I wish the guide had a little more to the series, but don’t fret you can always revert back to the original user’s guide or just pull up a command cheat sheet.  Either way you’ll be playing maniac mansion in no time and re-living those old memories I’m sure!

Published on: August 17, 2013 / Comments: None

Transferring data via audio FSK — modem style!


I stumbled on this awesome project called minimodem.  It’s a software FSK audio modem.  It allows you to encode and decode data as audio — just like dialup modems and fax machines used to.  This lead me to finding an Arduino project where Emmanuel is creating a long range temperature sensor that transmit’s temperature data over walkie-talkie radios and is decoded by minimodem.
On the Arduino side Emmanuel is using the RTTI Library. On the PC side it uses minimodem to de-modulate the encoded data.  Here’s a video of it in action.  What a great set of tools to add to the collection.   And you can make all sorts of cool projects, or hell just experimenting with the minimodem application itself.