A person holds a glass jar in their left hand and a spark plug in their right atop a white cylindrical canister. The jar and canister are sitting on top of a green cutting mat.

Spark Plug Becomes Glass Cutter

May 28, 2024 by Navarre Bartz 15 Comments

Sometimes a hack doesn’t need to be rocket science to be useful. Take for instance [MofigoDIY] using an old spark plug to build a glass cutter.

Sure, going to grab a glass cutter at the hardware store might be easy, but there’s something satisfying about going the DIY route. [MofigoDIY]’s version of this classic hack is a bit more refined than the quick and dirty route of smashing the spark plug alumina and hot gluing it into a tube.

After using a rotary tool to cut off the threads and expose the narrow part of the ceramic, [MofigoDIY] grinds it down to a fine point. This lets the spark plug itself become the handle, so you don’t need any additional parts to make the cutter. Toward the end of the video, a heated wire is used to break a glass jar apart after it was scored which might be of interest even if you already have a glass cutter. Once you’re finished making your glass cutter, make sure you dispose of any chips left over, since ceramic spark plug fragments are considered burglary tools in some areas.

Would you rather just build the glass up additively? How about using a laser cutter to sinter glass or 3D printing fused silica using a polymerized composite precursor?

Continue reading “Spark Plug Becomes Glass Cutter” →

Rotary Phone Lives On As Arduino Kitchen Timer

May 28, 2024 by Tom Nardi 5 Comments

It’s safe to say that few people still use rotary phones on a daily basis. Hell, most of us don’t even use landline telephones anymore. But just because these classic phones are no longer being used for their original purpose doesn’t necessarily mean they’re doomed to become e-waste.

[Scott-28] recently sent in a particularly well-documented project that turned an antique rotary phone into a digital kitchen timer using an internal Arduino. While we’re not sure practical is a word most folks would use to describe the resulting device, it’s certainly a conversation starter, and the details on how it was all implemented make for an interesting read.

As explained in the README, [Scott-28] first used an oscilloscope to figure out the pulses generated by the phone’s dial. From there, it was relatively easy to connect the dial to one of the pins on an Arduino Uno to determine which numbers the user had entered. The trickier part was getting the original bells to work — in North America, it takes up to 90 VAC to get a phone’s ringer going, which is quite a bit more than the lowly Arduino can handle.

Continue reading “Rotary Phone Lives On As Arduino Kitchen Timer” →

Grid Leak Radio Draws The Waves

May 23, 2024 by Al Williams 11 Comments

[Stephen McNamera] found a schematic for a grid leak radio online and decided to throw together a few tubes on a piece of wood and see how it worked. As you can see in the video below, it works well. The video is a bit light on details, but the web page he found the plans on also has quite a bit of explanation.

The name “grid leak detector” is due to the grid leak resistor between the grid and ground, in this case, a 2.7 megaohm resistor. The first tube does everything, including AM detection. The second tube is just an audio amplifier that drives the speaker. This demodulation method relies on the cathode to control grid conduction characteristics and was found in radios up to about the 1930s. The control grid performs the usual function but also acts as a diode with the cathode, providing demodulation. In a way, this is similar to a crystal radio but with an amplified tube diode instead of a crystal.

It looks like [Stephen] wound his own coil, and the variable capacitor looks suspiciously like it may have come from an old AM radio. The of the old screw terminal tube sockets on the wood board looks great. Breadboard indeed! What we didn’t see is where the 150 V plate voltage comes from. You hope there is a transformer somewhere and some filter capacitors. Or, perhaps he has a high-voltage supply on the bench.

While tubes are technologically passe, we still like them. Especially in old radios. Just take care around the high voltages, please.

Continue reading “Grid Leak Radio Draws The Waves” →

How To Lace Cables Like It’s 1962

May 20, 2024 by Donald Papp 34 Comments

Cable harnesses made wire management a much more reliable and consistent affair in electronic equipment, and while things like printed circuit boards have done away with many wires, cable harnessing still has its place today. Here is a short how-to on how to lace cables from a 1962 document, thoughtfully made available on the web by [Gary Allsebrook] and [Jeff Dairiki].

It’s a short resource that is to the point in all the ways we love to see. The diagrams are very clear and the descriptions are concise, and everything is done for a reason. The knots are self-locking, ensuring that things stay put without being overly tight or constrictive.

According to the document, the ideal material for lacing cables is a ribbon-like nylon cord (which reduces the possibility of biting into wire insulation compared to a cord with a round profile) but the knots and techniques apply to whatever material one may wish to use.

Cable lacing can be done ad-hoc, but back in the day cable assemblies were made separately and electrically tested on jigs prior to installation. In a way, such assemblies served a similar purpose to traces on a circuit board today.

Neatly wrapping cables really has its place, and while doing so by hand can be satisfying, we’ve also seen custom-made tools for neatly wrapping cables with PTFE tape.

This Tiny Game Boy Lets The Real Thing Play Online

May 13, 2024 by Tom Nardi 5 Comments

Back in 2021, [stacksmashing] found that it took little more than a Raspberry Pi Pico and some level-shifters to create a USB connection with the Game Boy’s link port. Add in the proper software, and suddenly you’ve got online multiplayer for the classic handheld. The hardware was cheap, the software open source, and a good time was had by all.

Inspired by both the original project and some of the hardware variations that have popped up over the years, [weiman] recently set out to create a new version of the USB link adapter that fits inside a miniature 3D printed Game Boy.

The big change from the original design is that this is using the far smaller, but equally capable, RP2040-Zero development board. This is mated with a SparkFun logic level converter board (or a clone of one from AliExpress) by way of a custom PCB that also includes the necessary edge connectors to connect directly to a Game Boy Link Cable.

Once the PCB is assembled, it’s dropped into the 3D printed Game Boy shell. [weiman] really worked some nice details into the case, such as aligning the d-pad and buttons in such a way that pressing them engages either the RESET or BOOTSEL buttons on RP2040-Zero. The screen of the printed handheld also lines up with the RGB LED on the top of the dev board, which can produce some cool lighting effects.

The original project from [stacksmashing] was an excellent example of the capabilities of the Pi Pico, and we’re glad to see it’s still being worked on and remixed by others. Even though the state of Game Boy emulation is nearly perfect these days, there’s still something to be said for working with the original hardware like this.

Reflecting On The State Of Game Boy Emulation In 2024

May 10, 2024 by Tom Nardi 14 Comments

Considering the decades that have passed since Nintendo’s Game Boy was considered the state-of-the-art in mobile gaming, you’d imagine that the community would have pretty much perfected the emulation of the legendary family of handhelds — and on the whole, you’d be right. Today, you can get open source emulators for your computer or even smartphone that can play the vast majority of games that were released between the introduction of the original DMG-1 “brick” Game Boy in 1989 through to the final games published for the Game Boy Advance in the early 2000s.

But not all of them. While all the big name games are handled at this point, there’s still a number of obscure titles (not all of which are games) that require specialized hardware accessories to properly function. To bring the community up to speed on where work is still required, [Shonumi] recently provided a rundown on the emulation status of every commercial Game Boy accessory.

Continue reading “Reflecting On The State Of Game Boy Emulation In 2024” →

80s Function Generator Is Both Beauty And Beast

April 23, 2024 by Tom Nardi 13 Comments

You know how the saying goes — they don’t make them like this anymore. It’s arguably true of pretty much any electronic device given the way technology changes over time, though whether or not it’s objectively a bad thing is going to vary from case to case.

As a practical example, take a look at the insides of this 80’s vintage HP 3314A function generator shared on the EEV Blog Forum by [D Straney].

With multiple PCBs stacked on top of each other, it’s hard to imagine that more components could possibly be crammed into it. One board in particular appears to be an entire Motorola 6800 computer, something which today would likely be replaced with a single microcontroller.

Which is actually why [D Straney] shared this with us in the first place. After seeing our recent post about a modern waveform generator that’s basically an empty box thanks to its modern components, they thought this would be a nice example of the opposite extreme.

So, is it a good or a bad thing that test equipment isn’t made this way anymore? Well, it’s hard to argue with the improved capabilities, smaller footprint, and reduced cost of most modern gear. But damn is the inside of this HP 3314A gorgeous. As one of the commenters on the page put it, hardware from this era was really a work of art.