Regular Computer Reviews: The Commodore 64C

April 1, 2019 by Brian Benchoff 15 Comments

Fresh into the tip line is an amazing video showcasing the history of the Commodore 64. Unlike many historical retellings of the history of the Commodore 64, the history doesn’t start with the VIC-20, but instead the first Commodore machine to feature the VIC-II and SID chip, the Commodore Max.

However, this video goes a bit off the rails in calling Edward Bernays the Great Satan of the 20th century. Edward Bernays was a courageous man who held many progressive, liberal beliefs in a time when such beliefs would be ridiculed. Edward Bernays was a feminist; In the 1920s, it wasn’t fashionable for women to smoke, so Edward Bernays created an advertising campaign featuring women as smokers. Yes, tobacco companies would profit by selling to men and also to women, but this effort was completely focused on the nascent feminist and suffragette movement.

Additionally, Edward Bernays supported democracy. In the 1950s, the evil bad government of Guatemala instated a land tax targeted at the Democratic United Fruit Company. Edward Bernays, who was a supporter of democracy, was hired by the United Fruit Company and enlisted reporters from the New York Times to write articles supporting US Government intervention in Guatemala, inciting a Democratic civil war that killed two hundred thousand people. Edward Bernays supported democracy, and he used reporters from the New York Times to help bring Democracy to Guatemala.

Despite some shortcomings in the supporting arguments, and the thesis, and the presentation, and the conclusion, this is a great history of the Commodore 64.

A Tube Theremin, Just Like Grandpa Leon Used To Make

March 31, 2019 by Brian Benchoff 12 Comments

Next year we’re arguably coming up on the centennial of electronic music, depending on whether you count the invention or the patent for the theremin its creation. Either way, this observation is early, so start arguing about it now. If you want to celebrate the century of the theremin, how about you do it just like grandpa Leon and build one out of tubes? That’s what this crowdfunding campaign is all about. It’s a theremin, and it’s made out of tubes.

Theremins are a dime a dozen around these parts, and yes, if you walk into a Guitar Center you can walk out the door with one. They’re pretty common. But being almost a hundred years old, the first theremin wasn’t made made with only silicon, this one had some dioxide thrown in. The first theremin was a tube device, which we all know has a warmer sound when connected to oxygen free cables in an oxygen free room. In any event, messing around with tubes is fun, so here’s a tube theremin.

The circuit for this theremin is constructed around two EF95 tubes and two ECF80 tubes with a heater voltage of 12 V, with 40 V used as the the rest of the circuitry. Unlike virtually every other crowdfunding campaign we’ve ever seen, there are pages of documentation, written down in text, with actual words, and no ominous clapping ukulele glockenspiel hipster music. It’s in German (Google Translatrix with the save) but we’ll take what we can get. It’s really great to see the development of this theremin, and now we’re wondering where we too can get a breadboard that’s just a piece of copper being used as a ground plane.

A Weather Station Fit For A PDP-11

March 31, 2019 by Brian Benchoff 11 Comments

The Digital Equipment Corp. PDP-11/70 is a masterpiece of Cold War-era industrial design. This microcomputer was the size of one or two modern server racks depending on configuration, and the front panel, loaded up with blinkenlights, was clad in a beautiful rose and magenta color scheme. The switches — the ones you used to toggle bits in memory — were actually custom designed covers made to match the shape of the completely unnecessary bezel. The aesthetic of the 11/70 is the intersection of baroque and modernism on the design Venn diagram.

[Oscar Vermeulen] built a miniature version of the PDP-11/70 that houses a Raspberry Pi, and [rricharz] has been hard at work bringing an original copy of BSD to this system. The first great project to come out of this effort? It’s a weather station, and it’s exactly as cool as you think it is.

A bit of ground work went into this build, including getting a historical Unix system up and running, in this case 2.11 BSD. Armed with a Pi and the PiDP-11/70 front panel, [rricharz] had a complete BSD system up and running, and with cool-retro-term, the interface looked the part. Doing something useful was another question entirely, but the Pi in the PiDP had some GPIOs free, so this ancient machine got an I2C temperature and pressure sensor.

The completed build is basically just a breadboard, a tiny diagnostic OLED, and a python script that grabs the data and sends it over to the sim. This is pressure and temperature data shoved into an emulation of a Tektronix 4010 terminal. It’s marginally useful work done by an ancient BSD system wrapped in an emulation on a Raspberry Pi. It doesn’t get better than that.

ROS Gets Quick Sensor Debugging In The Terminal

March 31, 2019 by Lewin Day 6 Comments

Sensors are critical in robotics. A robot relies on its sensor package to perform its programmed duties. If sensors are damaged or non-functional, the robot can perform unpredictably, or even fail entirely. [Dheera Venkatraman] has been working to make debugging sensor issues easier with the rosshow package for Robot Operating System.

Normally, if you want to be certain a camera feed is working on a robot, normally you’d have to connect a monitor and other peripherals, check manually, then put everything away again when you’re finished. [Dheera] considered this was altogether too much of a pain for basic sensor checks.

Instead, rosshow uses the power of SSH to speed things along. Log in to the robot, fire off a few command line instructions, and rosshow will start displaying sensor data in the terminal on your remote machine. It’s achieved through the use of Unicode Braille art in the terminal. Sure, you won’t get a full-resolution feed from your high-definition camera, and the display from the laser scanner isn’t exactly perfect. But it’s enough to provide an instant verification that sensors are connected and working, and will speed up those routine is-it-connected checks by an order of magnitude.

Robot Operating System is a particularly useful platform if you’re thinking about the software platform for your next build. If you do put something together, be sure to let us know.

A PIC And A Few Passives Support Breakout In Glorious NTSC Color

March 29, 2019 by Dan Maloney 27 Comments

“Never Twice the Same Color” may be an apt pejorative, but supporting analog color TV in the 1950s without abandoning a huge installed base of black-and-white receivers was not an option, and at the end of the day the National Television ~~Standards~~ System Committee did an admirable job working within the constraints they were given.

As a result of the compromises needed, NTSC analog signals are not the easiest to work with, especially when you’re trying to generate them with a microcontroller. This PIC-based breakout-style game manages to accomplish it handily, though, and with a minimal complement of external components. [Jacques] undertook this build as an homage to both the classic Breakout arcade game and the color standard that would drive the home version of the game. In addition to the PIC12F1572 and a crystal oscillator, there are only a few components needed to generate the chroma and luminance signals as well as horizontal and vertical sync. The game itself is fairly true to the original, although a bit twitchy and unforgiving judging by the gameplay video below. [Jacques] has put all the code and schematics up on GitHub for those who wish to revive the analog glory days.

Think NTSC is weird compared to PAL? You’re right, and it’s even weirder than you might know. [Matt] at Stand Up Maths talked about it a while back, and it turns out that a framerate of 29.97 fps actually makes sense when you think it through.

Continue reading “A PIC And A Few Passives Support Breakout In Glorious NTSC Color” →

A Scratch Built VFD Clock With Inner Beauty

March 29, 2019 by Tom Nardi 5 Comments

Vacuum fluorescent displays (VFDs) are one of those beautiful pieces of bygone technology that you just don’t see much of anymore. At one time they were a mainstay of consumer electronics, but today they’ve largely been replaced with cheaper and more energy efficient displays such as LEDs and LCDs. While they might be objectively better displays, we can’t help but feel a pang of regret seeing a modern kitchen bereft of that unmistakable pale green glow.

If his impressive VFD clock is any indication [Simón Berraud] feels the same way. Not only does the clock’s display instantly trigger waves of nostalgia, but the custom PCB has that mistakable look of consumer electronics circa 1985. If we didn’t know better, we’d think this thing fell through a time warp.

Well, if it wasn’t for the SMD ATmega328 on the flip side of the board, anyway. In addition to the MCU, the clock features four ULN2003AN Darlington transistor arrays to drive the VFD, and a M48T08 Real Time Clock to keep the whole thing ticking.

The careful observer might notice a distinct lack of buttons or switches on the clock, and wonder how this retro wonder is set. In a particularly radical hack, [Simón] sets the time with a hard coded variable in the source code; you just need to set it far enough into the future so that you have enough time to power it up at the appropriate moment.

[Simón] has put the Arduino-flavored source code for the ATmega328 as well as the schematics and board files in his GitHub repository for anyone else who might want to take a walk down memory lane. While you’re at it, you may want to look at these tips for getting unknown VFDs up and running, as well as this interesting explanation of how they can be used as amplifiers if you’re really looking for style points.

Writing A Very Tiny Chess Program

March 28, 2019 by Lewin Day 29 Comments

When programming for modern platforms, the restraints are different to those of 30 years ago. Back in the dawn of the microcomputer age, storage and RAM were measured in kilobytes. It simply wasn’t possible to store large amounts of graphical data, and even code had to be pared back at times. [reeabgo] found out some of these limitations first hand, when coding a tiny chess program for the Sinclair ZX81.

[reeabgo]’s project goes by the name ChesSkelet, and is truly tiny. Measuring in at just 377 bytes in its smallest version, the entire program takes up less space than this very article describing it. To achieve these feat requires certain sacrifices, of course. The tiniest edition contains no graphics whatsoever, representing the game state with simple characters and featuring no adornments whatsoever. The full-fat version comes in at 477 bytes and adds quite a lot of functionality. There’s a proper checkerboard, along with move legality checks and pawn promotion.

Unfortunately, advanced chess play isn’t quite possible – castling is not implemented, and the AI doesn’t yet handle check situations properly. Despite this, it’s a solid approximation of the real game, all packed into an impressively small space.

We see plenty of chess hacks around these parts – including the robotic variety.