DIY SSR For Mains Switching

Typical power strips have their sockets tightly spaced. This makes it cumbersome to connect devices whose wall warts or power bricks are bulky — you end up losing an adjoining socket or two. And if the strip has a single power switch, you cannot turn off individual devices without unplugging them.

Planning to tackle both problems together, [Travis Hein] built himself some custom Dual SSR Controlled Socket Outlets for his workbench. He also decided to add remote switching ability so he could turn off individual sockets via a controller, Raspberry Pi, smartphone app or most ideally, a nice control panel on his desk consisting of a bank of switches.

The easiest solution for his problem would have been to just buy some off-the-shelf SSR or relay modules and wire them up inside his sockets. But he couldn’t find any with the features he wanted, and SSR’s were a little bit on the expensive side. Also, we wouldn’t have a project to write about – sometimes even the simple ones can show us a thing or two.

For starters, he walks us through a quick and simplified primer on figuring out thermal dissipation for the triacs which will be used on his boards. This is tricky since the devices are connected directly to utility voltage so he needs to take care of track clearances, mechanical separation as well as safety. However, for his first board prototypes, he did not add any heat sinking for the triacs, thereby limiting their use to low current loads. Since the SSR also needs to have a wide control voltage range, he describes how the two transistor constant-current input block works to limit opto-triac LED current over a range of 2 V to 30 V.

Before he moves on to his next prototype, [Travis] is looking for feedback to improve his design, make it safer, and figure out if it can pass safety protocols. Let him know via comments below.

Fake Omron Relays are Worth What You Pay For Them

We love taking a look at fake components and [BigClive] has put together something really special in this category. When he saw he could buy suspiciously cheap Omron relays on eBay, he knew something must be fishy so he put in an order.

Some of the fakes he received are even marked Omrch instead of Omron, and your ear can detect the counterfeits by the varying sounds they make during operation. But of course [Clive’s] investigation goes much deeper than that. He started driving the relays to their rated voltages and taking temperatures with a FLIR camera.

The results were not surprising. At lower voltages the relays seemed to do okay, but closer to the maximums it’s obvious the components in the fakes are not rated for enough power to work. You can even see some charring of a resistor and its plastic holder from having too much power for the component’s rating. [Clive] actually replaced the errant resistor with a higher value resistor that reduces the current consumption and power dissipated.

He was also suspicious of the metal content of the contacts. You may think that doesn’t matter, but actually, the composition of relay contacts is critical to making reliable relay circuits. Depending on how much current flows and if the switching is dry (that is, made without current flowing) or not dictates use of different material.

The conclusion was that these relays might work for light duty projects, but for commercial projects or operating near the edge of the ratings, you want to give these a pass. If you do need a lot of low-power relays on the cheap — to compute a square root, or to build the whole computer — [Clive’s] process of testing and characterizing these fakes may come in handy for you.

Continue reading “Fake Omron Relays are Worth What You Pay For Them”

Because Building A Relay Computer Isn’t Hard Enough

For this year’s Hackaday Prize, we’re doing something special. We’re introducing achievements for Prize projects. Think of them as merit badges. If your Hackaday Prize project has multiple parts that come together into one unified, awesome whole, you get the Voltron achievement. If you’ve built a musical instrument that unexpectedly blows everyone’s minds, you get the Diva Plavalaguna Achievement. A select few entries will earn the Pickle Rick achievement. What’s this? It’s a jaw-dropping build that makes you shake your head in the totality of engineering perfection.

Here’s a project that nails this achievement. It’s a homebrew computer, made out of relays, that runs a custom instruction set. It’s built on Brainf*ck. It is, by far, the most absurd and amazing homebrew computer you’ve ever seen.

Several modules on a shelf, for scale.

First, the hardware. This CPU is built out of about 800 Soviet reed relays, RES64, RES55, and RES-43 relays, if you want some part numbers. These relays are mounted on logic cards connected to a backplane. Each backplane consists of thirty-two of these cards, and it takes two backplanes to build up a 16-bit full adder. The 16-bit instruction pointer and 16-bit address pointer each fit on half a backplane.

Moving up one level, the instruction set for this computer is based on Brainf*ck, with a few additions. The ‘+’ instruction adds to the current value, the ‘>’ instruction still increases the current memory address, but there are a few new instructions that make this CPU not an interminable world of suffering. There’s now a ‘write current data value to register’ commands, and logical XOR instructions.

Have relay-based computers been done before? Yes, and so have Brainf*ck ISAs. The combination is rarely seen, and we’ve never seen one that performs this well. Below, you can see a video of this computer counting at 500 operations per second (or 500 Hz from a frequency counter). This is really unimaginable with any other relay computer we’ve seen, and it’s all thanks to those really tiny Soviet tubes. If you want a Hackaday Prize project that’s jaw-dropping, here you go.

Continue reading “Because Building A Relay Computer Isn’t Hard Enough”

This is How the Fonz Would Play MP3s

Here at Hackaday, we love to see old hardware treated with respect. A lovingly restored radio or TV that’s part of our electronic heritage is a joy to behold, and while we understand the desire to stream media from a funky retro case, it really grates when someone throws away the original guts to make room for new electronics.

Luckily, this Seeburg jukebox wall remote repurposing is not one of those projects. [Scott M. Baker] seems to have an appreciation for the finer things, and when he scored this classic piece of Mid-Century Americana, he knew just what to do. These remotes were situated around diners and other hangouts in the 50s and 60s and allowed patrons to cue up some music without ever leaving their seats. They were real money makers back in the day, and companies put a lot of effort into making them robust and reliable.

[Scott]’s first video below shows the teardown of this unit; you can practically smell the old transformer and motor windings. His goal in the second video was to use the remote to control his Raspberry Pi jukebox; he wisely decided to leave everything intact and use the original electromechanically generated pulses to make selections. His analysis led to a nicely executed shield for his Pi which conditions the pulses and imitates coin drops; happily, the coin mechanism still works too, so you can still drop a quarter for a tune.

The remote is working well now, but [Scott] still needs to finish up a few odds and ends to bring this one home. But we love the look and the respect for tradition here, as we did when this juke got a Raspberry Pi upgrade to imitate a missing wall remote.

Continue reading “This is How the Fonz Would Play MP3s”

A Relay Calculator With DIY Neon Displays, Just Because

This looks like one of those projects that started out as a glimmer of an idea and led down a rabbit hole. But it’s a pretty cool rabbit hole that leads to homebrew neon seven-segment displays on a calculator with relay logic.

It’s a little thin on documentation so far, but that’s because [Mark Miller]’s build is one of those just-for-the-fun-of-it things. He started with a bag full of NE-2 tubes and the realization that a 3D-printed frame would let him create his own seven-segment displays. The frames have a slot for each segment, with a lamp and current limiting resistor tucked behind it; with leads brought out to pins and some epoxy potting, these displays would be hard to tell from a large LED seven-segment. Rolling your own displays has the benefit of being able to extend the character set, which [Mark] did with plus-minus and equal sign modules. All of these went together into a two-banger calculator — addition and subtraction only so far — executed in relays and vacuum tubes. Version 2.0 of the calculator regressed to all-relay logic, which must sound great.

We heartily regret the lack of a satisfyingly clicky video, but we’ll give it a pass since this is so cool. We’ll be watching for more on this project, but in the meantime, if you still need to get your click on, this electromechanical BCD counter should help.

The Noisiest Seven-Segment Display Ever

Few mechanical clocks are silent, and many find the sounds they make pleasant. But the stately ticking of an old grandfather clock or the soothing sound of a wind-up alarm clock on the nightstand are nothing compared to the clattering cacophony that awaits [ProtoG] when he finishes the clock that this electromechanical decimal to binary to hex converter and display will be part of.

Undertaken as proof of concept before committing to a full six digit clock build, we’d say [ProtoG] is hitting the mark. Yes, it’s loud, but the sound is glorious. The video below shows the display being put through its paces, and when the clock rate ramps up, the rhythmic pulsations of the relays driving the seven-segment flip displays is hypnotizing. The relays, one per segment of the Alfa Zeta flip displays, have DPDT contacts wired to flip a segment by reversing polarity. As a work in progress, [ProtoG] hasn’t shared many more details yet, but he promises to keep us up to date on the converter aspect of the circuit. Right now it just seems like a simple but noisy driver. We’ll be following this one with interest.

If you prefer your clocks quieter but still like funky displays, check out this mixed media circus-themed clock.

Continue reading “The Noisiest Seven-Segment Display Ever”

Counting is for Sheep: Use a Light to Fall Asleep

How do you get to sleep at night? For some of us, it can be the most difficult thing we do all day. Worrying about falling asleep and letting other intrusive thoughts in night after night only compounds the problem, as less sleep leads to depression which (for us) leads to even less sleep. We lay there, trapped inside a vortex of churning thoughts, imprisoned in a mind that feels like it’s malfunctioning and half-wishing for a future where instructor-led meditation videos can be beamed to the insides of our eyelids. In the meantime, there is FADing, the Fall Asleep Device.

FADing takes its cues from a relaxation technique that uses light to focus your attention and control your breathing. The light’s intensity waxes and wanes on a schedule designed to get you down from the average eleven breaths per minute to a zen-like six breaths per minute. You surrender to the light, breathing in as it intensifies and breathing out as it fades. There are commercial products that bring this technique to the bedroom, but they aren’t cheap and don’t offer much control. Fail to fall asleep in the prescribed window and you’re back to square one with one more thing to think about: buyer’s remorse.

[Youz] was inspired by these devices but dissatisfied with the price tag and lack of options, so he created his own version with a flexible window of operation that appeals to both back- and side-sleepers. It uses an Arduino Nano and two momentaries to control two LEDs, a relay to hold the power after startup, a 9V, and a diode to protect the Nano. One LED projects on the ceiling, and the other radiates through a slice of acrylic which has been shaded blue. One button is for power, and the other lets you add time by two-minute increments. You can see the build video after the break and then tell us how you’d do it with a 555, a coin cell, and a chunk of uranium glass in the comments.

Once you can focus on your breathing without a light, reuse that Nano to measure the quality of all that sleep you’re getting.

Continue reading “Counting is for Sheep: Use a Light to Fall Asleep”