An incredibly small gaming console with cartridges, each bearing an ATtiny10.

2024 Tiny Games Contest: An Epic Minimalist Entertainment System, Indeed

September 8, 2024 by 2 Comments

One way to keep things tiny is to make a system with cartridges where the brain lives on each cartridge instead of the platform itself. [Michael]’s Epic Minimalist Entertainment System (EMES) is one of those, and boy, is it tiny. EMES makes use of the ATtiny10, and they don’t get much AT-tinier than that.

A Plessey GPD340 display showing the word 'Hi'.This nearly microscopic console uses an equally Lilliputian display — a Plessey GPD340 vintage LED display, in fact. (Check out [Michael]’s reverse engineering project if you want to play around with these.) There are four ultra-small buttons for control and a buzzer for sound.

Now, the ATtiny10 is an 8Mhz microcontroller with 1KB of flash and 32 bytes of RAM. It has an 8-bit ADC and a somewhat surprisingly high four GPIO pins. But of course, that’s not enough. Not with the display, the four buttons, and the buzzer, so [Michael] had to come up with a way to multiplex everything to four GPIOs.

PB0 is shared between the buttons and the display’s serial data input. PB1 cleverly outputs the same PWM for both the brightness control and the buzzer. When the buzzer is needed, [Michael]’s code switches to a lower frequency and adjusts the duty cycle of the display to keep it readable. PB2 and 3 are serial clock inputs for the two display halves. Be sure to check it out the heated PONG action in the video after the break!

There’s still a little bit of time to enter the 2024 Tiny Games Contest! You have until Tuesday, September 10th, so head on over to Hackaday.IO and get started!

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Repairing A Hallicrafters S-120

September 8, 2024 by 2 Comments

[MIKROWAVE1] claims he’s not a radio repair guy, but he agreed to look at a malfunctioning Hallicrafters S-120 shortwave receiver. He lets us watch as he tries to get it in shape in the video below. You’ll see that one of his subscribers had done a great job restoring the radio, but it just didn’t work well.

Everything looked great including the restored parts, so it was a mystery why things wouldn’t work. However, every voltage measured was about 20V too low. Turns out that the series fuse resistor had changed value and was dropping too much voltage.

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The Hidden Crystal Method

September 8, 2024 by 25 Comments

Ever been working on a project and get stuck on one of those last little details?  That’s what happened to [Empire of Scrap].  He’s building an Ohio Scientific (OSI) superboard II replica. He wants it to be accurate down to the dates on the chips. It is quite an impressive build.  The problem is the crystal. OSI used large crystals, even by early 1980s standards. The crystal is in a large can with thick pins, like something you’d expect to find in old radio equipment. The problem is that this crystal package isn’t made anymore. 

The crystal had to be exactly 3.932160 MHz, and while [Empire] has a huge collection of vintage crystals, he didn’t have the right one from the 70s. He did, however, have that value in a modern crystal.  

The solution? Hide the new crystal in the can of an older one. The only problem is that crystals are sealed. The bottom appeared to be some sort of plastic or resin.  Gong after it with a side cutter, [Empire] realized it was glass!  Thankfully, none of it got in his eyes, though his hands may have taken a bit of a beating. 

With the old crystal’s shell hollowed out, [Empire] installed the modern device and potted everything in resin. The transplant worked. Now, all that’s left is to fire up the OSI and start hacking. 

Want to build a replica computer but don’t want to hunt down the parts? Check out [Taylor] and [Amy’s] build of this minipet. Regardless of the size of the case, crystals all work in the same way.

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How Hot Is That Soldering Iron?

September 7, 2024 by 8 Comments

It is common these days to have a soldering iron where you can set the temperature using some sort of digital control. But how accurate is it? Probably pretty accurate, but [TheHWCave] picked up a vintage instrument on eBay that was made to read soldering iron temperature. You can see the video below, which includes an underwhelming teardown.

The device is a J thermocouple and a decidedly vintage analog meter. What’s inside? Nearly nothing. So why did the meter not read correctly? And where is the cold junction compensation?

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Building A DIY MSX Mega Cartridge

September 7, 2024 by 9 Comments

[Mike] from Leaded Solder has a soft spot for old computers, and a chance encounter with a friend sent them deep down the deep hole that is the world of 80s and 90s-era Japanese home computers.  Many people playing with these machines have all kinds of issues to deal with, such as rotting cartridges, failing components, and just dirt and mank in critical places. [Mike] decided that working on an MSX-standard custom programmable cartridge would be sensible, but then got stuck on how the MSX cartridge mapping works.

The Konami 128K scheme uses 4 to 4-of-8 mapping.

You may recall that the MSX platform is not a single computer but a standard to which many (mainly Japanese) manufacturers designed their products. This disconnected the software writers from the hardware makers and is essentially a mirror of the IBM-PC clone scene.

The MSX is based around the Z80, which has a 16-bit address bus, restricting it to 64K of ROM or RAM. The MSX has two cartridge slots, an ‘internal’ slot for the BIOS and RAM and a fourth for ‘misc’ use. Each of these is mapped internally into the physical address space. The cartridge slots have 64K of addressable space mapped into the Z80 physical space.

If this was not complicated enough, many MSX games and applications exceeded this restriction and added a layer of mapping inside the cartridge using bank switching. A register in the cartridge could change the upper bits of the address allowing ROMs larger than 64K.

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Rendering Skin Transparent Using The Food Dye Tartrazine

September 7, 2024 by 21 Comments

Although we generally assume that opacity is the normal look for animals like us humans, this factoid is only correct for as long as you maintain the dissimilar optical refraction indices of skin and the more aqueous underlying structures. What if you could change the refraction index of skin? If you could prevent the normal scattering at the interface, you could reveal the structures underneath, effectively rendering skin transparent. [Zihao Uo] and others demonstrate this in a paper published in Science.

The substance they used was the common food dye known as tartrazine, which also goes by the names of Yellow 5 and E102 when it is used in food (like Doritos), cosmetics, and drugs. By rubbing the tartrazine into the skin of mice, the researchers were able to observe underlying blood vessels and muscles. Simulations predicted that the dye would change the refraction index mismatch between lipids and water which normally causes the light scattering that creates the skin’s opaque appearance. With the dye rubbed into the skin, the effect worked to a depth of about 3 mm, which makes it useful for some research and possible medical applications, but not quite at the ‘jellyfish-transparency’ levels that some seem to have imagined at the news.

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Get Thee To Git

September 7, 2024 by 21 Comments

While version control used to be reserved for big corporate projects, it is very mainstream these days. You can attribute much of that to Git, the software that has nearly displaced other version control. Git works well, it is versatile, and it scales well. It is easy to use as an individual developer or as part of a worldwide team. But Git is also one of those things that people don’t always study, they just sort of “pick it up” as they go. That motivated [Glasskube] to create “The Guide to Git I Never Had.”

If you are ready to click away because you are not a software person, hang on. Git is actually useful for many different kinds of data, and there are a number of hardware projects that use Git in some form. That’s especially true if the project has some code associated with it, but there are projects that consist of PCBs, reverse engineering documentation, or schematics.

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