Low Res Video Card Is Still Amazing Since It’s Made Out Of Logic Chips

July 7, 2019 by Brian Benchoff 33 Comments

[Ben Eater] has been working on building computers on breadboards for a while now, alongside doing a few tutorials and guides as YouTube videos. A few enterprising hackers have already duplicated [Ben]’s efforts, but so far all of these builds are just a bunch of LEDs and switches. The next frontier is a video card, but one only capable of displaying thousands of pixels from circuitry built entirely on a breadboard.

This review begins with a review of VGA standards, eventually settling on an 800×600 resolution display with 60 MHz timing. The pixel clock of this video card is being clocked down from 40 MHz to 10 MHz, and the resulting display will have a resolution of 200×150. That’s good enough to display an image, but first [Ben] needs to get the horizontal timing right. This means a circuit to count pixels, and inject the front porch, sync pulse, and back porch at the end of each horizontal line.

To generate a single horizontal line, [Ben]’s circuit first has to count out 200 pixels, send a blanking interval, then set the sync low, and finally another blanking interval before rolling down to the next line. This is done with a series of 74LS161 binary counters set up to simply count from 0 to 264. To generate the front porch, sync, and back porch, a trio of 8-input NAND gates are set up to send a low signal at the relevant point in a horizontal scan line.

The entire build takes up four solderless breadboards and uses twenty logic chips, but this isn’t done yet: all this confabulation of chips and wires does is step through the pixel data for the horizontal and vertical lines. A VGA monitor detects it’s in the right mode, but there’s no actual data — that’ll be the focus of the next part of this build where [Ben] starts pushing pixels to a monitor.

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This Chiptune Player’s Got What Nintendon’t

July 6, 2019 by Brian Benchoff 7 Comments

When it comes to chiptunes, the original Nintendo Entertainment System and the Game Boy get all the accolades. The OPL synths have all the fun. But there’s another chip out there in dusty old machines that is at least as interesting with a repertoire at least as influential as the Mega Man 2 OST. It’s the YM2612, the chip in the Sega Mega Drive/Genesis.

[natalie] created a portable device capable of playing back the files targeting the sound chips in this venerable machine. It’s the MegaGRRL, and it’s the iPod for the original Genesis sound tracks.

Inside the MegaGRRL is an ESP32 in the form of an ESP-WROOM-32 module. There is, of course a YM2612 chip in there, along with a headphone amplifier and a battery charger. The display is a fairly standard and cheap affair that’s 240 x 320 pixels in full color, and there are seven buttons on this device, because of course you need an A, B, and C button.

Combined with a 3D printed enclosure, the GameGRRL does exactly what it says it will: it plays all the music from old Sega games. Now, when you’re in the inevitable argument with someone over the fact that Michael Jackson wrote the Sonic 3 soundtrack, the proof is right in your pocket. Of if you want to jam out on the Toe Jam And Earl soundtrack, that’s right there too. You can check out the video demos below.

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Sprucing Up A Bell & Howell Model 34 Oscilloscope

July 4, 2019 by Tom Nardi 20 Comments

We’ll admit it, in an era when you can get a four channel digital storage oscilloscope with protocol decoding for a few hundred bucks, it can be hard not to see the appeal of analog CRT scopes from decades past. Sure they’re heavy, harder to use, and less capable, but they just look so cool. Who could say no to having one of these classic pieces of gear on their bench?

[Cody Nybo] certainly couldn’t. Despite the fact that he already has a digital scope, he couldn’t pass up the chance to add a Bell & Howell Schools Model 34 from circa 1973 to his collection. It needed a bit of TLC before it could be brought back into service, but now it’s all fixed up and ready to put in some work. Not bad for a piece of gear with nearly a half-century on the clock.

The restoration of the Model 34 was aided by the fact that [Cody] got the original manual and schematics for the scope in the deal, which he was kind enough to scan and upload for the rest of the class to enjoy. Those of you who have worked on older electronics can already guess where the scope needed the most love: all the capacitors needed to be swapped out for fresh ones. He also found a few resistors that were out of spec, and the occasional bad solder joint here and there.

Even if you’re not looking to repair your own middle-aged oscilloscope, his pictures of the inside of Model 34 are fascinating. The scope was sold as a kit, so the construction is surprisingly simple and almost entirely point-to-point. Of course, there’s something of a trade-off at work: [Cody] says it won’t display much more than 2.5 MHz before things start getting wonky. But then again, that’s a more than reasonable frequency ceiling for audio work and most hobbyist projects.

Oscilloscopes have come a long way since the days when they had to draw out their readings on a piece of paper. While newer devices have all but buried the classic analog scope, a beauty like this would still have a place of honor in our lab.

This Arduino Is Feeding The Fishes

July 2, 2019 by Lewin Day 11 Comments

Fish are easy to keep as pets, requiring little more than regular feeding to keep them happy in the short-to-medium term. If you’re going on holiday, it can be nice to know that your pets are being taken care of, but finding someone to take on the chore can be hard. [Trevor_DIY] doesn’t need to worry about that, however – he’s built an automatic feeder to handle the job.

The build uses an Arduino Uno as the brains, with the only additional hardware required being a stepper motor and driver. The stepper motor drives a 3D printed wheel, with 14 slots – each one holding one meal for the fish. This allows the feeder to deliver two meals a day for a full week before requiring attention.

The feeder is configured to feed a breakfast meal, then a dinner meal 8 hours later, and then wait 16 hours before breakfast comes around again. Rather than use a real-time clock, this is simply handled with the Arduino’s built in delay function. While it isn’t super accurate, this should be close enough over a week to keep the fish alive. We’d be interested as to just how far it drifts over time.

Overall, it’s a quick and tidy way to keep the pets going without a lot of fuss. Pet feeders are a popular project, as they solve a common problem faced by owners the world over; this one can even handle wet cat food. Video after the break.

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Why Fix A Remote When You Can Just Build A New Device?

July 2, 2019 by Lewin Day 17 Comments

Those who have been around the block, and the sun, a fair few times will know that they certainly don’t make ’em like they used to. It doesn’t particularly matter what “them” is; it’s merely a widely accepted fact that society has trended towards more disposable products over ones that have a long service life. [mcu_nerd] was suffering from this very problem, as their TV remote had its power button begin to fail. Of course, hackers don’t see problems – they merely see opportunities for projects.

[mcu_nerd] decided to skip repairing the TV remote, under the suspicion that disassembling the device would likely lead to its destruction. Instead, an Atmega328P development board was pressed into service as a replacement remote, with the addition of an IR LED and a push button. Whereas the TV-B-Gone existed as a device to cause havoc by switching televisions off, [mcu_nerd]’s TV-B-On does the opposite job.

A later revision was spun up with its own PCB, and features an Attiny85, which is more than capable of handling the job. Showing thoughts of the future in the design, there are provisions for extra buttons to be added should the project require a nicer enclosure, and a space for an external crystal if necessary.

These devices have a long and storied history; we reported on a particularly powerful version back in 2009.

A Doom-esque Port To The ATmega328

June 29, 2019 by Lewin Day 11 Comments

Doom holds a special place as one of the biggest games of the 1990s, as well as being one of the foundational blocks of the FPS genre. Long before 3D accelerators hit the market, iD Software’s hit was being played on computers worldwide, and later spread to all manner of other platforms. [David Ruiz] decided to build a cutdown version for everyone’s favourite, the ATmega328.

Due to the limited resources available, it’s not a direct port of Doom. [David] instead took some sprites and map data from the original game, and built a raycasting engine similar to that of Wolfenstein 3D. Despite the limited memory and CPU cycles, the basic game can run at between 8-11 FPS. There are fancy dithering tricks to help improve the sense of depth, a simplified enemy AI, and even a custom text library for generating the UI.

It’s a great example of what can be done with a seemingly underpowered part. We’ve seen similar work before, with Star Fox replicated on the Arduboy. A hacker’s ingenuity truly knows no bounds.

A Super Tidy School Bus RV Conversion

June 28, 2019 by Lewin Day 18 Comments

Many of us have seen an old bus for sale for a tantalizingly low price, and begun thinking about the possibilities. [EpiclyEpicEthan1] is someone who took the next step, bought the bus, and got to work converting it to an RV, with impressive results.

The bus in question is a 2002 International RE3000, which in its former life had helped move school children and barrels of pool chemicals to and fro. The project began, as many do, with a full teardown of the interior. With this done, the floor was treated to remove rust and repainted. Insulation and new plywood boards were then installed, and the fit-out began.

The amount of work involved in the build is immense. There’s a master bedroom, auxiliary bedroom, bathroom, and kitchen area. It’s a fully featured RV in every sense of the word, and yes, there is hot water. There was also significant work done to improve the driving experience, with switches relocated, lights added, and a reversing camera installed for easier parking.

Overall, it’s an impressive project that should serve as great inspiration to anyone wanting to attempt something similar. Then again, if your means are a little more limited, you could always go for a Corolla build.