Split Flap Clock Keeps Time Thanks To Custom Frequency Converter

June 23, 2019 by Dan Maloney 6 Comments

Why would anyone put as much effort into resurrecting a 1970s split-flap clock as [mitxela] did when he built this custom PLL frequency converter? We’re not sure, but we do like the results.

The clock is a recreation of the prop from the classic 1993 film, Groundhog Day, rigged to play nothing but “I Got You Babe” using the usual sound boards and such. But the interesting part was getting the clock mechanism keeping decent time. Sourced from the US, the clock wanted 120 VAC at 60 Hz rather than the 240 VAC, 50 Hz UK standard. The voltage difference could be easily handled, but the frequency mismatch left the clock running unacceptably slow.

That’s when [mitxela] went all in and designed a custom circuit to convert the 50 Hz mains to 60 Hz. What’s more, he decided to lock his synthesized waveform to the supply current, to take advantage of the long-term frequency control power producers are known for. The write-up goes into great detail about the design of the phase-locked loop (PLL), which uses an ATtiny85 to monitor the rising edge of the mains supply and generate the PWM signal that results in six cycles out for every five cycles in. The result is that the clock keeps decent time now, and he learned a little something too.

If the name [mitxela] seems familiar, it’s probably because we’ve featured many of his awesome builds before. From ludicrous-scale soldering to a thermal printer Polaroid to a Morse-to-USB keyboard, he’s always got something cool going on.

Overengineering The Humble USB Power Bank

June 5, 2019 by Tom Nardi 21 Comments

Back in the flip phone days, you could get through the whole weekend before you had to even think about plugging the thing in. But as the processing power of our mobile devices increased, so to did their energy consumption. Today you’re lucky if your phone doesn’t die before you make it home at the end of the day. To avoid the horrors of having to live without their mobile devices, many people have resorted to lugging around small “power banks” to keep their phones topped off.

That said, the “Ultimate 18650 Power Bank” created by [Kennedy Liu] is on a whole new level. Only true Road Warriors need apply for this particular piece of kit. Inside the 3D printed enclosure is…well, pretty much everything. It’s got an internal inverter to power your AC devices, a Qi wireless charging coil, an adjustable DC output, displays for all relevant voltages, and naturally plenty of USB ports to charge your gadgets. Oh, and some RGB LEDs tossed in for good measure.

[Kennedy] packed a lot of hardware into this relatively small package, and in the video after the break, shows off exactly how everything is arranged inside of this power bank. A big part of getting the whole thing together is the 3D printed frame, which includes carefully designed insets for all of the key components. So if you want to build your own version, you’ll need to get the exact same hardware he used to make sure the puzzle fits together. Luckily, he’s provided links for all the relevant components for exactly that purpose.

Now, you might be wondering about the wisdom of packing all this electronic gear into a thermoplastic enclosure. But [Kennedy] has thought about that; in addition to tacking a heatsink onto pretty much everything, he’s added fans for active cooling and a fairly robust thermal overload protection scheme. By mounting thermally controlled switches to the heatsinks of the high-output components, the system can cut power to anything getting too hot before it has a chance to melt the plastic (or worse).

Most of the DIY power banks we’ve seen in the past have been little more than a simple collection of 18650 cells, so it’s interesting to see one with so much additional functionality packed in. Admittedly some elements of the construction are, to quote the great Dave Jones, “a bit how ya doin.” But with some refinements we think it would be a very handy device to have in your arsenal.

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Adventures In Power Outage Hacking

January 29, 2019 by Dan Maloney 33 Comments

The best type of power outage is no power outage, but they will inevitably happen. When they do, a hacker with a house full of stuff and a head full of ideas is often the person of the hour. Or the day, or perhaps the week, should the outage last long past the fun little adventure phase and become a nuisance or even an outright emergency.

Such was the position that [FFcossag] found himself in at the beginning of January, when a freak storm knocked out power to his community on a remote island in the middle of the Baltic Sea. [FFcossag] documented his attempts to survive the eight-day outage in vlog form, and although each entry is fairly long, there’s a lot to be learned from his ordeal. His main asset was a wood cook stove in the basement of the house, which served as his heat source. He used a car radiator and a small water pump to get some heat upstairs – a battery bank provided the power for that, at least for a while. The system evolved over the outage and became surprisingly good at keeping the upstairs warm.

The power eventually came back on, but to add insult to injury, almost as soon as it did, the ground-source heat pump in the house went on the fritz. A little sleuthing revealed an open power resistor in the heat pump control panel, but without a replacement on hand, [FFcossag] improvised. Parts from a 30-year-old TV transmitter were close at hand, including a nice handful of power resistors. A small parallel network gave the correct value and the heat pump came back online.

All in all, it was a long, cold week for [FFcossag], but he probably fared better than his neighbors. Want to be as prepared for your next outage? Check out [Jenny]’s comprehensive guide.

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Vintage Audio Gear Gets A Display Upgrade

January 13, 2019 by Dan Maloney 4 Comments

The lengths the retrocomputing devotee must go to in order to breathe new life into old gear can border on the heroic. Tracing down long-discontinued parts, buying multiple copies of the same unit to act as organ donors for the one good machine, and when all else fails, improvising with current productions parts to get that vintage look and feel.

This LCD display backlighting fix for a vintage audio sampler falls into that last category, which was pulled off by [Inkoo Vintage Computer]. The unit in question is an Akai S1100 sampler, a classic from the late 1980s that had already been modified to replace the original floppy drive with a USB reader when the backlight on the LCD began to give out. Replacements for the original electroluminescent backlight are available, but [Inkoo] opted for a cheaper way out. An iPhone 6s 6 Plus backlight was an inexpensive option, if it could be made to fit. Luckily, [Inkoo] was able to trim the diffuser without causing any electrical issues. A boost converter was needed to run the backlight from the sampler’s 5 V DC rail, and interfacing the backlight’s flexible circuitry to the 80s-era copper wiring was a bit fussy, but the results were great. The sampler’s LCD is legible again, and looks just like it might have in the studio back when [Depeche Mode] and [Duran Duran] were using it to crank out hits.

As much as we like this repair, it doesn’t imply that EL is a dead technology. Far from it – [Ben Krasnow] is using it to create unique displays, and EL wire makes for some dazzling wearables. It doesn’t last forever, but while it does, it’s pretty neat stuff.

AV Synth Is Psychedelic Analog Mayhem

October 24, 2018 by Lewin Day 8 Comments

Digital video is cool and all, but it can’t compete with analog in terms of smooth, creamy glitches and distortion. [gieskes] has developed an analog audio-visual synthesizer that is a great example of the old-school retro visuals you can create with a handful of simple components.

Known as the 3TrinsRGB+1c, it’s available both assembled and in kit form. It’s probably best to start with the manual. Synthesis is achieved through the use of a HEF40106 hex inverting buffer – a cheap and readily available part that nonetheless provides for excellent results. Video can be switched between RGB oscillators and a series of inputs, and there are various controls to create those classic scrolling effects and other visual oddities.

Additionally, a series of connections to the underlying circuitry are broken out on a header connector. This allows for extra modules to be plugged in, and several designs are available to expand the unit’s capabilities.

Analog video isn’t used so much on a day-to-day basis anymore, but it’s a great technology to tinker and experiment with. We’ve seen some of [gieskes] experiments in this arena before, too – like this Arduino video sampler. Video after the break.

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You’ll Flip For This 7404 IC Motherboard Fix

October 20, 2018 by Tom Nardi 35 Comments

We often lament that the days of repairable electronics are long gone. It used to be you’d get schematics for a piece of gear, and you could just as easily crack it open and fix something as the local repairman — assuming you had the knowledge and tools. But today, everything is built to be thrown away when something goes wrong, and you might as well check at the end of a rainbow if you’re searching for a circuit diagram for a new piece of consumer electronics.

But [Robson] writes in with an interesting story that gives us hope that the “old ways” aren’t gone completely, though they’ve certainly changed for the 21st century. After blowing out his laptop’s USB ports when he connected a suspect circuit, he was desperate for a fix that would fit his student budget (in other words, nearly zero). Only problem was that he had no experience fixing computers. Oh, and it takes months for his online purchases to reach him in Brazil. Off to a rocky start.

His first bit of luck came with the discovery he could purchase schematics for his laptop online. Now, we can’t vouch for the site he used (it sure isn’t direct from Dell), but for under $5 USD [Robson] apparently got complete and accurate schematics that let him figure out what part was blown on the board without even having to open up the computer. All he had to do was order a replacement IC (SY6288DAAC), and solder it on. It took two months for the parts to arrive, and had to do it with an iron instead of a hot air station, but in the end, he got the part installed.

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How To Build An Inverter, And Why Not To Bother

September 30, 2018 by Dan Maloney 30 Comments

It’s ridiculously easy to lay hands on a cheap DC-to-AC inverter these days. They’re in just about every discount or variety store and let you magically plug in mains powered devices where no outlets exist. Need 120- or 240-VAC in your car? No problem – a little unit that plugs into the lighter socket is available for a few bucks.

So are these commodity items worth building yourself? Probably not as [GreatScott!] explains, but learning how they work and what their limitations are will probably help your designs. The cheapest and most common inverters have modified square wave outputs, which yield a waveform that’s good enough for most electronics and avoids the extra expense of producing a pure sinusoidal output. He explains that the waveform is just a square wave with a slight delay at the zero-crossing points to achieve the stepped pattern, and shows a simple H-bridge circuit to produce it. He chose to drive the output section with an Arduino, to easily produce the zero-crossing delay. He uses this low-voltage inverter to demonstrate how much more complicated the design needs to get to overcome the spikes caused by inductive loads and the lack of feedback from the output.

Bottom line: it’s nice to know how inverters work, but some things are better bought than built. That won’t stop people from building them, of course, and knowing what you’re doing in this field has been worth big bucks in the past.

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