1-Pixel Pacman

I usually see retro-gaming projects using tiny screens with a fair number of pixels (64×64) but what I really like is the look of making every pixel count. With this in mind I built 1-Pixel Pac-Man, the classic coin-op experience but with characters that consist of just one pixel. Playing a throw-back like this wouldn’t be the same without some vintage controls so I picked up an Atari joystick, patched it into a microcontroller, and started coding. Check it out:

Smartmatrix Bundle

This piece of hardware made the project build really easy: the Smartmatrix. [Louis Beaudioin] developed the Smartmatrix and it’s been in the Hackaday Store for a while now. The display module itself is a commodity item that is used in LED billboards. There are shrouded headers on the back of the panels, to the left and right sides, which allow them to be daisy chained. The Smartmatrix PCB plugs into one of these shields, provides a soldering footprint for the Teensy 3.1 which drives the display, and gives you the wiring to connect screw terminals from the PCB to the power terminals on the module. Why the need for beefy power jumpers? At full white the thing can draw about 3.5A — don’t worry there’s a power supply included in the bundle.

Also integral to making this look good is the diffuser panel which is frosted acrylic. The Smartmatrix is designed to be housed in a shadowbox frame; it even includes a frame backer board with a cut-out for the Teensy 3.1 so it can be programmed without opening the thing up. I like looking at the guts so I’m leaving my free floating until I come up with an interesting way to mount everything as one unit.

Programming Pac-Man from the Ground Up


If you haven’t looked into it before, the ghost AI and gameplay details for Pac-Man are absolutely brilliant. [Toru Iwatani] did a masterful job with the original, and you should take a look at all of the analysis that has been done over the years. The best collection I could find was the Pac-Man Dossier and I based most of my code on the rules described there.

Basically the ghosts have two modes, chase and scatter. The modes set the enemy targets differently; to points at the four corners of the board in scatter, and to points relative to the player in chase. The relative part is key; only the red enemy actually chases you. Another one of them looks at the red enemy’s distance and angle, and targets the reflection of that vector. Really easy, really clever, and results in enemy behavior that’s believable. It isn’t just the enemy movement, little touches like a speed penalty (1/60 of a second) for each dot the player gobbles up means the enemies can catch up if you continuously eat, but you can escape by taking the path already-eaten.

Library, DMA, and Extra Hardware

The hardware and software running the Smartmatrix made the display portions of the project really simple. First off, the Teensy 3.1 is fast, running at 96MHz in this case. Second, it has Direct Memory Access (DMA) which [Louis] used in the Smartmatrix library. This means that driving the display takes almost no CPU time at all, leaving the rest for your own use. This example of a game is under-utilizing this power… it’s totally capable of full-motion video and calculating amazing visualizations on the fly.

The PCB hosting the Teensy 3.1 breaks out several pins to one side. I’m not sure what I’ll add in the future so I actually used the extra surface-mount IO pins on the bottom of the Teensy to connect the Atari joystick (which is simply a set of switches). The are enough pads for two joysticks so I used pin sockets to interface the Teensy to the PCB so that I can get to it again later.

The kit also includes an IR receiver and remote, and also a microSD card to loading animations (there’s an SD socket on the PCB). The bundle in the Hackaday Store is a kit you solder yourself, but [Louis’] company, Pixelmatix, has a Kickstarter running for fully-assembled versions that come with a black remote and sound-visualization hardware.

Future Improvements

The game is fully working, but there are a few key things that I really want to add. The Teensy 3.1 has a single DAC pin available. I’m fairly certain the original coin-op game had mono audio. It should be possible to reproduce the sound quite accurately with this board. That would really make the project pop.

There are also a bunch of touch-ups that need to happen. I’d like to add an animation when the player is eaten by an enemy, and a countdown before the level restarts. The score, shown in binary on the right column, should be scrolled out in decimal when the game ends, and what’s a coin-op recreation without a high-score screen?

Vintage Computers At Maker Faire

It’s no secret that Maker Faire is highly geared toward the younger crowd. This doen’t mean the Faire is completely devoid of the historic; the Bay Area Maker Faire is right in the heart of the beginnings of the computer industry, and a few of the booths are showing off exactly how far computers have come over the last forty years.

Superboard[Vince Briel] of Briel Computers has a booth showing off his wares, mostly modern reimaginings of vintage computers. His table is loaded up with replica 1s, a board that’s much smaller but still completely compatible with the Apple I. The MicroKIM made an appearance, but the crown jewel is [Vince]’s Superboard III, a replica of the Ohio Scientific Superboard II. It’s your basic 6502 computer with 32k of RAM, but unlike just about every other modern retrocomputer out there, [Vince] put the keyboard right on the main board.

The switches are Cherry MX, the keys are from WASDkeyboards. [Vince] is actually getting a lot of interest in making modern ASCII keyboards to replace the old and busted boards that came in the home computers of the 70s and 80s. That might be a project [Vince] will release sometime in the future.

[Jef Raskin], the Swift Card, and the Canon Cat

[Steve Jobs] may have been the father of the Macintosh, but he was, by no means, solely responsible for the Mac. It was a team of people, and when you talk about the UI of the Mac, the first name that should come up is [Jef Raskin].

One of [Jef Raskin]’s finest works was the Swyft Card, an add-on to the Apple II that was basically just a ROM card that had an OS and Forth interpreter on it. The distinguishing feature of the Swyft card was the use of ‘leap’ keys, a simple way to change contexts when using the computer. We’ve seen replicas of the Swyft card before, courtesy of [Mike Willegal] at the Vintage Computing Festival East.

Woodie[Dwight Elvey] of the vintage-computer.com forum brought a few extra special items related to [Raskin] and the Canon Cat. The first was a Swyft card installed in an Apple IIe. The second was a prototype Swyft computer, with SERIAL NUMBER 1 printed on a Dymo label and fixed to the case.

The ‘woodie’, as [Dwight] calls it, has two 1.44 MB disk drives, of which half of the disk is actually usable. [Dwight] didn’t take the machine apart, but I’m 99% sure the CRT in it is the exact same tube found in early 9″ Macs.

Also in [Dwight]’s display is a production Swyft computer and a Canon Cat, the final iteration of [Jef Raskin]’s idea of what a text-based computer should be.

The vintage-computer booth also had a few interesting retrocomputers including a Commodore 128D, the Apple made, Bell & Howell branded Apple II, and an Amiga 2000. Right next door was the Computer History Museum, who brought a very kid-friendly storage medium display. Showing a 10-year-old an 8″ disk is fun.

Retrotechtacular: The Early Days of CGI

We all know what Computer-Generated Imagery (CGI) is nowadays. It’s almost impossible to get away from it in any television show or movie. It’s gotten so good, that sometimes it can be difficult to tell the difference between the real world and the computer generated world when they are mixed together on-screen. Of course, it wasn’t always like this. This 1982 clip from BBC’s Tomorrow’s World shows what the wonders of CGI were capable of in a simpler time.

In the earliest days of CGI, digital computers weren’t even really a thing. [John Whitney] was an American animator and is widely considered to be the father of computer animation. In the 1940’s, he and his brother [James] started to experiment with what they called “abstract animation”. They pieced together old analog computers and servos to make their own devices that were capable of controlling the motion of lights and lit objects. While this process may be a far cry from the CGI of today, it is still animation performed by a computer. One of [Whitney’s] best known works is the opening title sequence to [Alfred Hitchcock’s] 1958 film, Vertigo.

Later, in 1973, Westworld become the very first feature film to feature CGI. The film was a science fiction western-thriller about amusement park robots that become evil. The studio wanted footage of the robot’s “computer vision” but they would need an expert to get the job done right. They ultimately hired [John Whitney’s] son, [John Whitney Jr] to lead the project. The process first required color separating each frame of the 70mm film because [John Jr] did not have a color scanner. He then used a computer to digitally modify each image to create what we would now recognize as a “pixelated” effect. The computer processing took approximately eight hours for every ten seconds of footage. Continue reading “Retrotechtacular: The Early Days of CGI”

Non-Arduino powered by a piece of Computing history

Sometimes it is a blessing to have some spare time on your hands, specially if you are a hacker with lots of ideas and skill to bring them to life. [Matt] was lucky enough to have all of that and recently completed an ambitious project 8 months in the making – a Non-Arduino powered by the giant of computing history – Intel’s 8086 processor. Luckily, [Matt] provides a link to describe what Non-Arduino actually means; it’s a board that is shield-compatible, but not Arduino IDE compatible.

He was driven by a desire to build a single board computer in the old style, specifically, one with a traditional local bus. In the early days, a System Development Kit for Intel’s emerging range of  microprocessors would have involved a fair bit of discrete hardware, and software tools which were not all too easy to use.

Back in his den, [Matt] was grappling with his own set of challenges. The 8086 is a microprocessor, not a microcontroller like the AVR, so the software side of things are quite different. He quickly found himself locking horns with complex concepts such as assembly bootstrapping routines, linker scripts, code relocation, memory maps, vectors and so on. The hardware side of things was also difficult. But his goal was learning so he did not take any short cuts along the way.

[Matt] documented his project in detail, listing out the various microprocessors that run on his 8OD board, describing the software that makes it all run, linking to the schematics and source code. There’s also an interesting section on running Soviet era (USSR) microprocessor clones on the 8OD. He is still contemplating if it is worthwhile building this board in quantities, considering it uses some not so easy to source parts. If you are interested in contributing to the project, you could get lucky. [Matt] has a few spares of the prototypes which he is willing to loan out to anyone who can can convince him that they could add some value to the project.

Continue reading “Non-Arduino powered by a piece of Computing history”

Pac-Man Clock Eats Time, Not Pellets

[Bob’s] Pac-Man clock is sure to appeal to the retro geek inside of us all. With a tiny display for the time, it’s clear that this project is more about the art piece than it is about keeping the time. Pac-Man periodically opens and closes his mouth at random intervals. The EL wire adds a nice glowing touch as well.

The project runs off of a Teensy 2.0. It’s a small and inexpensive microcontroller that’s compatible with Arduino. The Teensy uses an external real-time clock module to keep accurate time. It also connects to a seven segment display board via Serial. This kept the wiring simple and made the display easy to mount. The last major component is the servo. It’s just a standard servo, mounted to a customized 3D printed mounting bracket. When the servo rotates in one direction the mouth opens, and visa versa. The frame is also outlined with blue EL wire, giving that classic Pac-Man look a little something extra.

The physical clock itself is made almost entirely from wood. [Bob] is clearly a skilled wood worker as evidenced in the build video below. The Pac-Man and ghosts are all cut on a scroll saw, although [Bob] mentions that he would have 3D printed them if his printer was large enough. Many of the components are hot glued together. The electronics are also hot glued in place. This is often a convenient mounting solution because it’s relatively strong but only semi-permanent.

[Bob] mentions that he can’t have the EL wire and the servo running at the same time. If he tries this, the Teensy ends up “running haywire” after a few minutes. He’s looking for suggestions, so if you have one be sure to leave a comment. Continue reading “Pac-Man Clock Eats Time, Not Pellets”

The Original Seven (Eight?) Segment Display

The seven-segment LED display is ubiquitous. But how old do you think the fundamental idea behind it is? You nixie tube fans will be thinking of the vacuum-tube era, but a reader sent us this patent filed in 1908 where [Frank W. Wood] builds a numeric display with plain-vanilla light bulbs, slots cut in wood, and lots of wires.

The OCR on the patent is poorly done — you’re going to want to download the PDF and read it locally. But as it states in the patent, “Referring again to Fig. 1, the novel arrangement of the lamp compartments will be readily understood.”

Technically it’s not a seven-segment display at all. [F.W. Wood] designed these really nice-looking “4”s with the diagonal heads, and so he needed eight segments per digit. But the basic idea shines through, if you pardon the pun.

The other figures demonstrate the machine that’s used to send the signals to light up the lights. It’s a rotating drum with the right contacts on the bottom side to make connections and turn on the right lights at the other end. Low tech, but it’s what was available at the time.

We’re stoked that we’re not responsible for wiring this thing up, and we’re a bit awed by how old the spirit behind one of our most ubiquitous technologies is.

Thanks to [mario59] for the nostalgic tip!

Dual Porting a C64 Flash Cart

The old cartridges for the Commodore 64 use EEPROMs to store their data, and the newer Flash carts use either a Flash chip or an SD card to put a whole bunch of games in a small plastic brick. [Stian] and [Runar] thought that wasn’t good enough – they wanted to program cartridges in real time, the ability to reboot the C64 without ever touching it, and a device for coding and testing. What they came up with is the latest advance in Commodore cartridge technology.

The device presents 8k of memory to the C64, but it doesn’t do this with Flash or an EEPROM. Instead, [Stian] and [Runar] are using a dual-port static RAM, specifically one from the IDT7005 series. This chip has two data busses, two address busses, and /CE, /OE, and R/W lines for either side of the chip, allowing other digital circuits to be connected to one small section of the C64’s memory.

Also in the cart is an ATmega16 running V-USB to handle the PC communications. It takes about 1 to 1.5 seconds to transfer an entire 8k over to the cartridge, but this chip can read and write the RAM along with the C64 simultaneously.

If you want a box that will give you the ability to put ever game in existence on a single cartridge, this isn’t the one. However, if you want to write some C64 games and do some live debugging, this is the one for you. The Eagle files are available, and there’s a video demo below.

Continue reading “Dual Porting a C64 Flash Cart”