Back To Basics With A 555 Deep Dive

February 17, 2024 by Dan Maloney 28 Comments

Many of us could sit down at the bench and whip up a 555 circuit from memory. It’s really not that hard, which is a bit strange considering how flexible the ubiquitous chip is, and how many ways it can be wired up. But when was the last time you sat down and really thought about what goes on inside that little fleck of silicon?

If it’s been a while, then [DiodeGoneWild]’s back-to-basics exploration of the 555 is worth a look. At first glance, this is just a quick blinkenlights build, which is completely the point of the exercise. By focusing on the simplest 555 circuits, [Diode] can show just what each pin on the chip does, using an outsized schematic that reflects exactly what’s going on with the breadboarded circuit. Most of the demos use the timer chip in free-running mode, but circuits using bistable and monostable modes sneak in at the end too.

Yes, this is basic stuff, but there’s a lot of value in looking at things like this with a fresh set of eyes. We’re impressed by [DiodeGoneWild]’s presentation; while most 555 tutorials focus on component selection and which pins to connect to what, this one takes the time to tell you why each component makes sense, and how the values affect the final result.

Curious about how the 555 came about? We’ve got the inside scoop on that.

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Enthusiast Seeks Keycap Designer For Alphasmart NEO

February 17, 2024 by Kristina Panos 14 Comments

If you were an American kid in the 1990s, chances are good that you may have been issued a little word processing machine by your school called an Alphasmart. These purpose-built machines created by an offshoot of Apple engineers were way cheaper than the average laptop at the time, and far more prepared to be handed over to the average child. The salesmen used to drop-kick them at trade shows to demonstrate their toughness.

Today, these machines are revered by writers, especially those who participate in NaNoWriMo, a yearly event in which people attempt to write the first draft of a novel during the month of November.

The Alphasmart NEO, NEO2, and Dana models are of particular note because they each have a really nice scissor-switch membrane keyboard. Yeah, that’s right. A really nice membrane keyboard.

The problem is that things wear out with time. As you may have guessed, Alphasmart is no longer around, and so they can’t offer replacement keycaps. Can you help by creating a 3D model? [E.F. Nordmed] and many others would sure appreciate it.

You may remember the Alphasmart NEO from these very pages. We sure do love them for distraction-free writing.

Wireless All The Things!

February 17, 2024 by Elliot Williams 48 Comments

Neither Tom Nardi nor I are exactly young anymore, and we can both remember a time when joysticks were actually connected with wires to the computer or console, for instance. Back then, even though wireless options were on the market, you’d still want the wired version if it was a reaction-speed game, because wireless links just used to be too slow.

Somehow, in the intervening years, and although we never even really noticed the transition as such, everything has become wireless. And that includes our own hacker projects. Sure, the ESP8266 and other WiFi-capable chips made a big difference, but I still have a soft spot in my heart for the nRF24 chipset, which made at least point-to-point wireless affordable and easy. Others will feel the same about ZigBee, but the point stands: nothing has wires anymore, except to charge back up.

The reason? As this experiment comparing the latency of many different wireless connections bears out, wireless data links have just gotten that good, to the point that the latency in the radio is on par with what you’d get over USB. And the relevant software ecosystems have made it easier to go wireless as well. Except for the extra power requirement, and for cases where you need to move a lot of data, there’s almost no reason that any of your devices need wires anymore.

Are you with us? Will you throw down your chains and go wireless?

WoWMIPS: A MIPS Emulator For Windows Applications

February 17, 2024 by Maya Posch 12 Comments

When Windows NT originally launched it had ports to a wide variety of platforms, ranging from Intel’s x86 and i860 to DEC’s Alpha as well as the MIPS architecture. Running Windows applications written for many of these platforms is a bit tricky these days, which [x86matthew] saw as a good reason to write a MIPS emulator. This isn’t just any old emulator, though. It maps 32-bit Windows applications targeted at the MIPS R4000 CPU to an x86 CPU instead. Since both platforms run in a little-endian, 32-bit mode, this theoretically should be a walk in the park.

The use of the Windows PE executable format is also the same, so the first task was to figure out how to load the MIPS PE binary in a way that made sense for an x86 platform. This involved some reverse-engineering of the MIPS ntdll.dll file to figure out how relocations on that platform were handled. Following this, the mapping of the instructions of the R4000 CPU to the (CISC) x86 ISA was pretty easy. Only Floating Point Unit (FPU) support was left as a future challenge. Memory access was left as direct access, meaning no sandboxing or isolation, for simplicity’s sake.

The final task was mapping the native API calls, which call almost directly into the underlying host Windows OS’s API, with a bit of glue logic. With all of this done, Windows NT applications originally written for 1990s MIPS ran just fine on a modern-day x86_64 PC running Windows — as long as you don’t need an FPU (for now).

Salvaged Meter Movements Really Pop In This DIY VU Meter Bridge

February 17, 2024 by Dan Maloney 3 Comments

If you’re going to build a nice VU meter bridge for the recording studio, the first thing you need is a nice pair of VU meters. But lest you think it’s as easy as putting some meters into a nice box and calling it a day, think again.

This project comes to us from [Frank Olson], whose projects usually incorporate wood as part of the mechanism, as with his famous wooden ribbon microphone. This build does indeed use wood, and to excellent effect, but only in the project’s final enclosure. Before that, [Frank] had salvaged a pair of good-looking moving coil meters from an old tape recorder. He muddled through some ideas before settling on a design. A NE5532 dual-channel audio buffer module is used as a preamp, with each channel feeding into a bridge rectifier before heading to the meter. Wisely, [Frank] chose to illuminate the meters with their existing incandescent bulbs, so a small DC-DC supply was added to provide the necessary 8 volts.

As for the enclosure, that’s where [Frank]’s experience working with veneers paid off. He chose mahogany, carefully cut all the pieces to shape with a knife, and glued it all up with CA glue — at least we assume it was CA; based on previous efforts, he uses a lot of the stuff. The tung oil finish looks fantastic, and the completed build aesthetic looks great! The video below shows it all.

If you need some backstory on the VU meter, we can help with that.

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Sneaky Fix Gets Simon Back Up And Running

February 16, 2024 by Lewin Day 6 Comments

Simon was a cutting-edge “computer controlled game” when it launched back in 1978. It would flash out a pattern of ever-increasing length and you had to copy it if you didn’t want to lose. The name, obviously inspired by the traditional folk game of Simon Says. [Robert] recently found an original vintage Simon game, but it had been non-functional for many years. However, with some astute analysis and repair, he was able to get it working again.

Upon powering the unit up, the best [Robert] could get out of it was some flickering of the lights, nothing more. It wouldn’t start a game or respond to button presses. Eventually, probing around showed [Robert] that the TMS1000 microcontroller wasn’t running properly. It seemed to concern the connection to the “Game Mode” selector switch. Thanks to a fault and the multiplexed layout of the controls, it was appearing to the microcontroller that a button was always pressed at all times.

The solution [Robert] landed on was to separate out the signal from the Game Mode switch by socketing the TMS1000 and lifting the relevant pin. . The signal was then wired back up to the chip via diodes so that it wouldn’t interfere with the other outputs and inputs on the chip used to read the other buttons. This meant that the unit was locked into the single main game mode, but it did get it operational again.

It may not be a complete repair, but it nonetheless saved this unit from complete failure. Failing a repair of your own unit, you can always build one with modern hardware instead. Video after the break.

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Bioluminescent Glowing Petunias Are Now A Thing

February 16, 2024 by Lewin Day 45 Comments

Outside of the depths of the ocean, or cartoons, we’re not typically accustomed to plant life glowing or otherwise generating its own light. However, science is helping to change all that. Now, you can order some bioluminescent plants of your very own from Light Bio.

Light Bio is a startup company working in the synthetic biology space. It’s not content to simply pursue research behind closed doors, and is now sharing its work with the public. It has announced it plans to start selling petunias to U.S. customers which literally glow with the magic of bioluminescence.

Petunias don’t normally glow, but with some modifications, it turns out they can be convinced to. It took a large team of 26 scientists to figure out how to boost bioluminescence in plants, by isolating and optimizing genes sourced from various glowing mushroom species.

The plants will be available from April, with Light Bio planning to sell them as “Firefly Petunias.” It might sound like scary sci-fi tech, but the USDA has apparently already signed off on Light Bio selling these to the public.

Something’s been bothering me, though. It’s at the edge of my memory… I think my old housemate played bass for Glowing Petunias back in 2015. Something like that, anyway… video after the break.

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