A VFD Wall Thermometer

December 28, 2019 by Tom Nardi 5 Comments

Want to build something using VFD tubes, but don’t need yet another clock project? In that case, this wall mounted temperature and humidity display created by [commanderkull] might be exactly what you’re looking for. With six IV-11 tubes, this display is a practical way to add some of that gorgeous blue-green glow to your home or office.

The USB powered display uses a XL6009 and an XL7015 to provide the 24 V and 1.8 V needed by the IV-11 tubes, respectively. Both of which can be disconnected with jumpers to shut down the tubes without powering off the entire device, a useful feature when programming and debugging the display’s ATmega328P microcontroller. Each tube is connected to the ATmega with an 74HC595 shift register and a UDN2981 driver. Temperature and humidity data is provided, perhaps unsurprisingly, by the exceptionally common DHT22 sensor.

If you are looking to build another clock with these style tubes, there’s certainly enough prior art out there to get you started. We’ve also seen faux VFDs that you could use for either project, just in case you aren’t looking to deal with the voltage requirements and relative rarity of the real thing.

Hard Drive Data Recovery – Why Not DIY?

December 24, 2019 by Lewin Day 53 Comments

Hard drive failures can be tough to bear, particularly for the average person who doesn’t back up. When it comes to data recovery, there’s always those bleating from the sidelines that it’s a job that must be left to the professionals. However, this is Hackaday, not HireSomeoneADay, so [Matt]’s video on do-it-yourself hard drive repair is just what we like to see.

The video begins with plugging the non-functional drive into an external caddy, and using a microphone to listen to the sounds it makes. Upon analysis, [Matt] concludes that the drive is not spinning up, and suspects the heads may be stuck, causing the problem. When tapping the drive fails to unstick the heads, the next step is disassembly.

Despite the best advice from armchair commentators, this can be achieved at home without a clean room. [Matt] opens the drive carefully, and notes that the head is indeed stuck to the platter, instead of sitting in its home position. Using a screwdriver, the platters are rotated in their usual direction while gentle pressure is applied to pull the head away, being sure to use a light touch to avoid ripping the heads off entirely. With this done, the drive is reassembled and powered up. Amazingly, the repair is successful, and data is able to be recovered!

It’s important to note that this is a highly risky procedure, and not guaranteed to succeed. Truly valuable data should be left to the professionals, but if you’re skint or simply unbothered, it doesn’t hurt to have a go yourself. Be sure to avoid dust entering the drive, and take care not to touch the platters themselves. Of course, if you brick the device, you can always scavenge it for parts. Video after the break.

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Interactive Core Memory Shield Helps Explains The Past

December 19, 2019 by Gerrit Coetzee 9 Comments

[Andy Geppert] sends in his incredibly clever interactive core memory shield.

In a great display of one hacker’s work being the base for another’s, [Andy] started out with [Jussi Kilpelainen]’s core memory shield for Arduino. As he was playing with the shield he had a desire to “see” the core memory flipping and got the idea to add an LED matrix aligned behind the individual cores.

The first iteration worked, but it only showed the state that the Arduino believed the core memory to be in. What he really wanted was a live read on the actual state. He realized that an Adafruit Featherwing 8×8 matrix display also fits behind the core memory. Now the LEDs update based on the read state of the core memory. This allows him to flip the individual bits with a magnetic stylus and see the result. Very cool.

You can see a video of it working after the break.

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Watch A Sand-Cast Slingshot Made, From Start To Finish

December 18, 2019 by Donald Papp 13 Comments

Sand-casting metal parts is a technique that has been around for a very long time, but it can be educational to see the process from start to finish. That’s exactly what [Frederico] shows us with his sand-cast slingshot of his own design, and it’s not bad for what he says is a first try!

First, [Frederico] makes a two-part green sand mold of the slingshot body. Green sand is a sand and clay mix, and is only green in the sense that it is wet or “raw” and not further processed. After the mold is made, it’s time to melt aluminum in the propane-powered furnace, and the molten aluminum is then poured into the mold.

After cooling, [Frederico] breaks up the sand to reveal the rough cast object. There is post-processing to do in the form of sprues to cut and some flashing around the seams to remove, but overall it looks to have turned out well. You can watch the whole process in the video, embedded below.

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Escher: Etch-a-Sketch As A Service

December 18, 2019 by Tom Nardi 5 Comments

For better or for worse, the tech world has fully committed to pushing as many of their products into “The Cloud” as possible. Of course, readers of Hackaday see right through the corporate buzzwords. It’s all just a fancy way of saying you have to poke some server over the Internet every time you want to use the service. In a way, [Matt Welsh] has perfectly demonstrated this concept with Escher. It’s a normal Etch-a-Sketch, but since somebody else owns it and you’ve got to have an active Internet connection to use it, that makes it an honorary citizen of the Cloud.

Escher takes the form of a 3D printed mount and replacement knobs for the classic drawing toy that allow two NEMA 17 steppers to stand in for human hands. Thanks to the clever design, [Matt] can easily pull the Etch-a-Sketch out and use it the old fashioned way, though admittedly the ergonomics of holding onto the geared knobs might take a little getting used to. But who wants to use their hands, anyway?

In terms of the electronics, the star of the show is the the Adafruit Feather HUZZAH32 development board, paired with a motor controller that can provide 12 V to the steppers. [Matt] even went through the trouble of making a custom voltage regulator PCB that steps down the stepper’s voltage to 5 V for the Feather. Totally unnecessary, just how we like it.

For the software folks in the audience, [Matt] goes into considerable detail about how he got his hardware talking to the web with Google Firebase. Even if the Internet of Sketches doesn’t quite tickle your fancy, we imagine his deep-dive on pushing G-Code files from the browser into the Feather will surely be of interest.

It probably will come as little surprise to hear this isn’t the first automatic Etch-a-Sketch that’s graced these pages over the years, but this might be the most fully realized version we’ve seen yet.

Simple “Computer” From The ’60s Now 3D Printed

December 17, 2019 by Bryan Cockfield 11 Comments

Now is an amazing time to be involved in the hobby electronics scene. There are robots to build, cheap microcontrollers which are easy to program, and computers themselves are able to be found for very low prices. That wasn’t the case in the 1960s though, where anyone interested in “electronics” might have had a few books about ham radios or some basic circuits. If you were lucky though, you may have found a book from 1968 that outlined the construction of a digital computer made out of paperclips that [Mike Gardi] is hoping to replicate.

One of the first components that the book outlines is building an encoder, which can convert a decimal number to binary. In the original book the switches were made from paper clips and common household parts, but [Mike] is using a more reliable switch and some 3D prints to build his. The key of the build is the encoder wheel and pegs, which act as the “converter” between decimal and binary and actually performs the switching.

It’s a fairly straightforward build, but by working through the rest of the book the next steps are to build two binary encoders and hook all of them up to an ALU which will give him most of a working computer from long lost 1960s lore. He’s been featured recently for building other computers from this era as well.

Thanks to [DancesWithRobots] for the tip!

Chaining Together A 16×2 Bubble LED Display

December 10, 2019 by Tom Nardi 27 Comments

We’ve recently noticed an uptick of interest in so-called “bubble displays”: vintage alphanumeric LEDs which are probably best remembered as being used in watches and calculators before the LCD took over. Today they’re available as surplus or even salvage for literally pennies, but unfortunately they only provide four or five characters to work with. Or rather they did, until [sjm4306] built a board that chains them into a 16×2 array.

For the princely sum of 71 cents each, [sjm4306] picked up ten HPDL-1414 displays, each capable of showing four characters. He then designed a PCB that would accept eight of the displays at once, and even thought ahead to use headers so they could be pulled out and swapped as needed. Of course mounting them is only half the battle, you still need to drive the things.

Each display has its own dedicated driver chip on board, but trying to address each one individually would take far too many pins. So [sjm4306] opted to use a trio of 74HC595 shift registers, allowing him to toggle the three dozen pins necessary over SPI from a microcontroller. He’s even written up a little library and some example code that you can grab on the project’s Hackaday.io page.

Unfortunately, after all his hard work, tragedy struck. As these displays were a couple decades old given their date code, [sjm4306] thought he would clean them up with a bit of alcohol before their big video debut. But whatever plastic the clear panels are made of didn’t take kindly to the IPA, and they all shattered. They still work, but it’s definitely a quirk to keep in mind if you pick up some of these vintage displays to play with yourself.

In the past we’ve seen a much smaller PCB that allowed similar displays to more easily be interfaced with modern microcontrollers; perfect if you just want to bang out a few retro LED characters with a minimum of fuss.

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