If you were selling computers in the early 1960s you faced a few problems, chief among them was convincing people to buy the fantastically expensive machines. But you also needed to develop an engineering force to build and maintain said machines. And in a world where most of the electrical engineers had cut their teeth on analog circuits built with vacuum tubes, that was no easy feat.

To ease the transition and develop some talent, Digital Equipment Corporation went all out with devices like the DEC H-500 Computer Lab, which retrocomputing wizard [Michael Gardi] is currently building a reproduction of. DEC’s idea was to provide a selection of logic gates, flip flops, and other elements of digital electronics that could be hooked together into more complicated circuits. We can practically see the young engineers in their white short-sleeve shirts and skinny ties laboring over the H-500 in a lab somewhere.

[Mike] is fortunate enough to have an original H-500, but he wants anyone to be able to build one. His project page and the Instructables post go into great detail on how he made everything from the front panel to the banana plug jacks; almost everything in the build aside from the wood frame is custom 3D printed to mimic the original as much as possible. But the pièce de résistance is those delicious, butterscotch-colored DEC rocker switches. Taking some cues from custom switches he had previously built, he used reed switches and magnets to outfit the 3D printed rockers and make them look and feel like the originals. We can’t wait for the full PDP build.

Hats off to [Mike] for another stunning reproduction from the early years of the computer age. Be sure to check out his MiniVac 601 trainer, the Digi-Comp 1 mechanical computer, and the paperclip computer. If you’d like to pick [Mike’s] brain about this or any of his other incredible projects, he’ll be joining us for a Hack Chat in August.

Thanks to [Granzeier] for the tip!

source https://hackaday.com/2020/06/28/reproduction-1960s-computer-trainer-really-pushes-our-buttons/

All by itself, a calculator based on an Arduino isn’t necessarily very novel. However, [Volos] has a nice board that, of course, looks like a calculator. There are 16 keys and an LED display. But it seems to us the real value would be using this as a base for other projects.

As an inexpensive development board, it’s handy to have a simple processor with a keyboard and a display. There’s some extra I/O pins and the first example in the video below shows using the setup as a simple organ, for example. We’d love to see an option to replace the LED with an LCD and maybe even some different CPU options, as well.

The board is essentially an Arduino with a standard USB to serial chip and a MAX7219 display driver. Of course, you could breadboard up all of these things, but it wouldn’t be as neat looking. One unusual thing about the keyboard is that it is not multiplexed. Each button has a label that indicates what Arduino pin it connects with. So key 6 connects to pin 6 and pin A2 connects to the key marked =/A2.

With the availability of inexpensive PC boards, we’re seeing many nice designs out there that would be easy to repurpose for other things. For example, we thought this board would easily run the Kim Uno, with some modifications to the I/O routines. Might even be able to work out a clone of an even older computer to fit on the board.

source https://hackaday.com/2020/06/28/calcuino-is-an-arduino-calculator/

On some 2011 Macbook Pro models, there is a tendency for the Radeon GPU to fail. This should mean game over for the computer, but surprisingly salvation is offered by its having not one but two GPUs on board. The Intel processor also has a GPU, and Apple use a pile of logic in an FPGA to switch at will between them. The community have produced fresh FPGA code to revive a dead Mac on its Intel GPU, but at the expense of losing brightness control. [Ayilm1] has brought back the brightness with a clever BGA reworking hack that gains access to a brightness control line present on the Intel BD82HM65 Platform Controller Hub chip but not used in the Macbook.

We’re used to impressive soldering work here at Hackaday, and we’ve seen our share of wiring direct to the balls on an upturned BGA chip. This is a similar idea but at another level, as a section of the top insulation on an in-place BGA is removed to expose the microvia above the ball carrying the required signal. A tiny wire is soldered to the exposed pad and taken to a piece of copper tape stuck down to provide mechanical strength, and a piece of enameled copper wire is run from that to the other side of the PCB where lies its destination. It comes with FPGA code to take advantage of it, but even for non-Macbook owners, it’s an extremely impressive piece of work. It’s not the first fine-soldering Macbook fix we’ve seen, either.

Thanks [lightpink784] for the tip.

source https://hackaday.com/2020/06/28/a-dead-macbook-gpu-shouldnt-stop-you-with-this-bga-soldering-hack/

USB-C has brought the world much more powerful charging options in a slimline connector. With laptop chargers and portable battery packs using the standard, many with older hardware are converting their devices over to work with USB-C. [victorc] was trying to do just that, purchasing an adapter cable to charge a ThinkPad. Things didn’t quite work out of the box, so some hacking was required.

The problem was the power rating of the adapter cable, versus the battery pack [victorc] was trying to use. In order to allow the fastest charging rates, the adapter cable features a resistor value which tells the attached Lenovo laptop it can draw up to 90 W. The battery pack in question could only deliver 45 W, so it would quickly shut down when the laptop tried to draw above this limit.

To rectify this, [victorc] looked up the standard, finding the correct resistor value to set the limit lower. Then, hacking open the cable, the original resistor on the Lenovo connector was removed, and replaced with the correct value. With this done, the cable works perfectly, and [victorc] is able to charge their laptop on the go.

For all the benefits USB-C has brought, there’s been plenty of consternation, too. Whether this clears up, only time will tell!

source https://hackaday.com/2020/06/28/hacking-a-thinkpad-usb-c-adapter/

USB-C has brought the world much more powerful charging options in a slimline connector. With laptop chargers and portable battery packs using the standard, many with older hardware are converting their devices over to work with USB-C. [victorc] was trying to do just that, purchasing an adapter cable to charge a ThinkPad. Things didn’t quite work out of the box, so some hacking was required.

The problem was the power rating of the adapter cable, versus the battery pack [victorc] was trying to use. In order to allow the fastest charging rates, the adapter cable features a resistor value which tells the attached Lenovo laptop it can draw up to 90 W. The battery pack in question could only deliver 45 W, so it would quickly shut down when the laptop tried to draw above this limit.

To rectify this, [victorc] looked up the standard, finding the correct resistor value to set the limit lower. Then, hacking open the cable, the original resistor on the Lenovo connector was removed, and replaced with the correct value. With this done, the cable works perfectly, and [victorc] is able to charge their laptop on the go.

For all the benefits USB-C has brought, there’s been plenty of consternation, too. Whether this clears up, only time will tell!

source https://hackaday.com/2020/06/28/hacking-a-thinkpad-usb-c-adapter/

USB-C has brought the world much more powerful charging options in a slimline connector. With laptop chargers and portable battery packs using the standard, many with older hardware are converting their devices over to work with USB-C. [victorc] was trying to do just that, purchasing an adapter cable to charge a ThinkPad. Things didn’t quite work out of the box, so some hacking was required.

The problem was the power rating of the adapter cable, versus the battery pack [victorc] was trying to use. In order to allow the fastest charging rates, the adapter cable features a resistor value which tells the attached Lenovo laptop it can draw up to 90 W. The battery pack in question could only deliver 45 W, so it would quickly shut down when the laptop tried to draw above this limit.

To rectify this, [victorc] looked up the standard, finding the correct resistor value to set the limit lower. Then, hacking open the cable, the original resistor on the Lenovo connector was removed, and replaced with the correct value. With this done, the cable works perfectly, and [victorc] is able to charge their laptop on the go.

For all the benefits USB-C has brought, there’s been plenty of consternation, too. Whether this clears up, only time will tell!

source https://hackaday.com/2020/06/28/hacking-a-thinkpad-usb-c-adapter/

Along with the substantial rise in bread baking over the last few months, many people have been whipped into a frenzy over this tasty-looking frothy coffee beverage called Dalgona. It’s like a caffeinated meringue made from instant coffee, sugar, boiling water, and a whole lot of air that is then spooned onto milk or milk and ice.

Sure, you can use a whisk to mix it up if you don’t mind doing so continuously and vigorously for at least a full three minutes. [HimanshuS8] quickly got tired of making his wife’s coffee this way, and designed a small electric hand mixer especially for this task. [HimanshuS8] happens to be a hardware design engineer, which is why it looks so minimalist and beautiful.

The inside is just as beautiful, mixing junk bin parts like the 6 V motor from a cassette deck with printed gears and beaters. At the risk of reviving an old debate, we hope [HimanshuS8] used food-safe filament for those. If you replicate this, you could try to design it around standard metal beaters instead. Check out the demo after the break while you wait for the water to boil.

Coffee makes everything better, including 3D prints — the high cellulose content in coffee waste has been shown to drastically improve print strength.

source https://hackaday.com/2020/06/27/diy-hand-mixer-whips-coffee-into-shape/

Cheap 433 MHz wireless switches are a tempting way to enter the world of home automation, but without dedicated hardware, they can be less easy to control from a PC. That’s the position [TheStaticTurtle] was in, so the solution was obvious. Build a USB 433 MHz transceiver.

At the computer end is a CH340 USB-to-serial chip and the familiar ATmega328 making this a compact copy of the Arduino. At the RF end are a pair of modules for transmit and receive, unexpectedly with separate antennas. This device is a second revision, after initial experiments with a single antenna connector and an RF switch proved not to work. On the software side the Arduino uses the rc-switch library, while on the PC side there’s a Python library to make sense of it all. The code and hardware files are all on GitHub, should you wish to experiment.

The problem of making a single antenna transceiver is not for the faint-hearted RF engineer, as while diode switches seem on paper to deliver the goods, they can be extremely difficult to get right and preserve linearity. We’re curious that a transceiver module wasn’t used instead, but we’re guessing that cost played a significant part in the equation.

Over the years we’ve featured quite a few fascinating 433 MHz projects, like this TP-Link router conversion.

source https://hackaday.com/2020/06/27/433-on-a-stick/

We always look forward to a new blog post by [Ken Shirriff] and this latest one didn’t cure us of that. His topic this time? Comparing two Game Boy audio chips. People have noticed before that the Game Boy Color sounds very different than a classic Game Boy, and he wanted to find out why. If you know his work, you won’t be surprised to find out the comparison included stripping the die out of the IC packaging.

[Ken’s] explanation of how transistors, resistors, and capacitors appear on the die are helpfully illustrated with photomicrographs. He points out how resistors are notoriously hard to build accurately on a production IC. Many differences can affect the absolute value, so designs try not to count on exact values or, if they do, resort to things like laser trimming or other tricks.

Capacitors, however, are different. The exact value of a capacitor may be hard to guess beforehand, but the ratio of two or more capacitor values on the same chip will be very precise. This is because the dielectric — the oxide layer of the chip — will be very uniform and the photographic process controls the planar area of the capacitor plates with great precision.

We’ve decapsulated chips before, and we have to say that if you are just starting to look at chips at the die level, these big chips with bipolar transistors are much easier to deal with than the fine and dense geometries you’d find even in something like a CPU from the 1980s.

We always enjoy checking in with [Ken]. Sometime’s he’s taking apart nuclear missiles. Sometimes he is repairing an old computer. But it is always interesting.

source https://hackaday.com/2020/06/27/comparing-bare-silicon-on-two-game-boy-audio-chips/

Unless you’re in a carnival funhouse, mirrors are generally dead flat and kind of boring. Throw in some curves and things get interesting, especially when you can control the curve with a touch of your finger, as with this variable surface convex mirror.

The video below starts off with a long but useful review of conic constants and how planes transecting a cone can create circles, parabolas, or ellipses depending on the plane’s angle. As [Huygens Optics] explains, mirrors ground to each of these shapes have different properties, which makes it hard to build telescopes that work at astronomical and terrestrial distances. To make a mirror that works over a wide range of distances, [Huygens Optics] built a mirror from two pieces of glass bonded together to form a space between the front and rear surface. The front surface, ground to a spherical profile, can be deformed slightly by evacuating the plenum between the two surfaces with a syringe. Atmospheric pressure bends the thinner front surface slightly, changing the shape of the mirror.

[Huygens Optics] also built an interferometer to compare the variable mirror to a known spherical reference. The data from the interferometer was fed to a visualization package that produced maps of the surface shape, which you can easily see changing as the pressure inside the mirror changes. Alas, a deeper dive into the data showed the mirror to be less than perfect, but it’s fascinating to think that a mirror can flex enough to change from elliptical to almost parabolic with nothing more than a puff of air.

We’ve seen a couple of interesting efforts from [Huygens Optics] before, including this next-level spirit level. He’s not all about grinding glass, though — witness this investigation into discriminating metal detectors.

source https://hackaday.com/2020/06/27/variable-mirror-changes-shape-under-pressure/

Bats are fascinating animals, and despite all the myth and creepiness surrounding them, they really remind one more of a drunk bird lost in the night sky than the blood-sucking creature they’re often made out to be. Of course, some really fall into that category, and unlike actual birds, bats don’t tend to grace us with their singsong — at least not in ways audible for us humans. But thanks to bat detectors, we can still pick up on it, and [Marcel] recently built a heterodyne bat detector himself.

The detector is made with a 555, an MCP6004 op amp, and a 4066 analog switch — along with a bunch of passives — and is neatly packed into a 3D-printed case with a potentiometer to set the volume and center frequency for the detection. The bat signal itself is picked up by a MEMS microphone with a frequency range [Marcel] found suitable for the task. His write-up also goes in all the mathematics details regarding heterodyning, and how each component plays into that. The resulting audio can be listened to through a headphone output, and after putting together an adapter, can also be recorded from his smartphone. A sample of how that sounds is added in his write-up, which you can also check out after the break.

In case you want to give it a try yourself, [Marcel] put all the design files and some LTSpice simulations on the project’s GitHub page. If you are curious about bat detectors in general and want to read more about them, follow [Pat Whetman] down that rabbit hole, or have a look at this one made in Python for something more software-focused.

(Banner image by Signe Allerslev)

source https://hackaday.com/2020/06/27/what-does-the-bat-say-tune-in-with-this-heterodyne-detector/

Bats are fascinating animals, and despite all the myth and creepiness surrounding them, they really remind one more of a drunk bird lost in the night sky than the blood-sucking creature they’re often made out to be. Of course, some really fall into that category, and unlike actual birds, bats don’t tend to grace us with their singsong — at least not in ways audible for us humans. But thanks to bat detectors, we can still pick up on it, and [Marcel] recently built a heterodyne bat detector himself.

The detector is made with a 555, an MCP6004 op amp, and a 4066 analog switch — along with a bunch of passives — and is neatly packed into a 3D-printed case with a potentiometer to set the volume and center frequency for the detection. The bat signal itself is picked up by a MEMS microphone with a frequency range [Marcel] found suitable for the task. His write-up also goes in all the mathematics details regarding heterodyning, and how each component plays into that. The resulting audio can be listened to through a headphone output, and after putting together an adapter, can also be recorded from his smartphone. A sample of how that sounds is added in his write-up, which you can also check out after the break.

In case you want to give it a try yourself, [Marcel] put all the design files and some LTSpice simulations on the project’s GitHub page. If you are curious about bat detectors in general and want to read more about them, follow [Pat Whetman] down that rabbit hole, or have a look at this one made in Python for something more software-focused.

(Banner image by Signe Allerslev)

source https://hackaday.com/2020/06/27/what-does-the-bat-say-tune-in-with-this-heterodyne-detector/

Bats are fascinating animals, and despite all the myth and creepiness surrounding them, they really remind one more of a drunk bird lost in the night sky than the blood-sucking creature they’re often made out to be. Of course, some really fall into that category, and unlike actual birds, bats don’t tend to grace us with their singsong — at least not in ways audible for us humans. But thanks to bat detectors, we can still pick up on it, and [Marcel] recently built a heterodyne bat detector himself.

The detector is made with a 555, an MCP6004 op amp, and a 4066 analog switch — along with a bunch of passives — and is neatly packed into a 3D-printed case with a potentiometer to set the volume and center frequency for the detection. The bat signal itself is picked up by a MEMS microphone with a frequency range [Marcel] found suitable for the task. His write-up also goes in all the mathematics details regarding heterodyning, and how each component plays into that. The resulting audio can be listened to through a headphone output, and after putting together an adapter, can also be recorded from his smartphone. A sample of how that sounds is added in his write-up, which you can also check out after the break.

In case you want to give it a try yourself, [Marcel] put all the design files and some LTSpice simulations on the project’s GitHub page. If you are curious about bat detectors in general and want to read more about them, follow [Pat Whetman] down that rabbit hole, or have a look at this one made in Python for something more software-focused.

(Banner image by Signe Allerslev)

source https://hackaday.com/2020/06/27/what-does-the-bat-say-tune-in-with-this-heterodyne-detector/

How do you come up with new ideas? As much as it sometimes seems like they arrive in a flash out of the blue, they don’t just come out of nowhere. Indeed, we all have well-stocked mental toolboxes that say “this thing can be used to do that” and “if you want to get there, start here”.

One incredibly fertile generator of “new” ideas is simply putting old ideas next to each other and realizing that a chain of two or three can get you to someplace new. It just happened to me while listening to Mike and myself on this week’s Hackaday Podcast.

Here’s the elevator pitch. You take something like the player-pianoesque MIDI barrel piano that we featured last Thursday, and mix it together with the street-painting bicycle trailer that we featured on Friday. What do you get? A roll of paper that can be drawn on by normal kids, rolled up behind a bicycle, with a tank that they can pressurize with a bike pump, that will spray a pixelated version of their art as they roll down the sidewalk.

Now how can I make this real? One of my neighbors has a scrap bike trailer…

But see what I mean about ideas? I just took two existing ideas and rubbed them together, and in this case, they emitted sparks. And I’ve got a mental catalogue of all of the resources around me, some of which fell right into place. This role as fountain of good proto-ideas is why I started reading Hackaday fifteen years ago, and why it’s still a daily must-read for folks like us everywhere. A huge thank you to everyone who’s sharing! Read more Hackaday!

source https://hackaday.com/2020/06/27/nothing-comes-from-nowhere/