Keep Pedaling to Keep Playing

It’s been said that the best way to tackle the issue of childhood obesity would be to hook those children’s video game consoles up to a pedal-powered generator. Of course, this was said by [Alex], the creator of Cykill. Cykill interfaces an Xbox to an exercise bike, so to keep the video game going you’ll have to keep pedaling the bike.

While there is no generator involved in this project, it does mimic the effect of powering electronics from a one. The exercise bike has a set of communications wires, which are connected to a relay on the Xbox’s power plug. When the relay notices that the bike isn’t being pedaled enough, it automatically cuts power to the console. Of course, the risk of corrupting a hard drive is high with this method, but that only serves to increase the motivation to continue pedaling.

The project goes even further in order to eliminate temptation to bypass the bike. [Alex] super-glued the plug of the Xbox to the relay, making it extremely difficult to get around the exercise requirement. If you’re after usable energy instead of a daily workout, though, there are bikes out there that can power just about any piece of machinery you can imagine.

iPad, not Flux Capacitor, Brings DeLorean Back to the Future

Add a flux capacitor and a Mr. Fusion to a DeLorean and it becomes a time machine. But without those, a DeLorean is just a car. A 35-year old car at that, and thus lacking even the most basic modern amenities. No GPS, no Bluetooth — not even remote locks for the gullwing doors!

To fix that, [TheKingofDub] decided to deck his DeLorean out with an iPad dash computer that upgrades the cockpit experience, and we have to say we’re impressed by the results. Luckily, the space occupied by the original stereo and dash vents in the center console is the perfect size for an iPad mini, even with the Lightning cable and audio extension cable attached. A Bluetooth relay module is used to interface to the doors, windows, trunk, garage door remote, and outdoor temperature sensor. A WiFi backup camera frames the rear license plate. Custom software ties everything together with OEM-looking icons and a big GPS speedometer. The build looks great, adds functionality, and should make road trips a little easier.

When [TheKingofDub] finally gets sick of people complaining about where the BTTF guts are, maybe he can add a flux capacitor and time circuits.

[via r/electronics]

Vintage Telegraph Sounder Clicks Again

It’s sad, when you think about it: a retired railroad telegraph operator, who probably once pounded out code at 40 words per minute, with a collection of vintage sounders silently gathering dust on a shelf. [kthrace] decided to do something about that, and built this Morse sender to bring those old sounders back to life.

As archaic as Morse might seem, it’s a life skill, one the 92-year old former brass-pounder for whom this was built was eager to practice again. There are code practice oscillators, of course, but dits and dahs are no substitutes for the electromagnetic clicks and clacks that once filled this old fellow’s days. There’s not much information on the circuit, but it looks like [kthrace] chose a RedBoard to read Morse from an SD card and drive some relays to support up to four sounders; that’ll make a racket! The case is custom made and nicely complements the wood and brass of the J.H. Bunnell and Co. sounder, which still sounds great after all these years.

Test your Morse skills in the video below – copying code is a lot harder from a sounder than from an oscillator. Find yourself in need of practice? We’ve got you covered.

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Oscillating Fan Controller Used As Relay

The most brilliant hacks we see aren’t always the thousand-dollar, multi-year projects spanning every facet of engineering. Rather, the most ingenious projects are ones that take an everyday thing and use it in a simple but revolutionary way. By that measure, it’ll be hard to top [Robert]’s latest hack which uses the controller board from an everyday oscillating fan to build a three-way remote-controlled relay board.

Most oscillating fans have a speed selector switch. What that does might be somewhat different between different types of fan, but in general it will select either a smaller portion of the fan’s motor to energize or switch in a resistor which will have the same speed-lowering effect. [Robert]’s fan had little more than a triple-throw switch on the control board, so when he decided the fan wasn’t worth keeping anymore, he was able to re-purpose the control board into a general-use relay. As a bonus, the fan could be controlled by infrared, so he can also remote control whatever he decides to plug into his new piece of equipment.

While this simple hack might not change the world, it may give anyone with an old fan some ideas for other uses for its parts. If you want to do a little more work and get the fan itself running again, though, it is possible to rebuild the whole thing from the ground up as well.

Relay Computer Starts with an Adder that Makes a Racket

Computers built using discrete logic chips? Seen it. Computers from individual transistors? Impressive, but it’s been done. A computer built out of electromechanical relays? Bring on the ozone!

The aptly named [Clickity Clack]’s new YouTube channel promises to be very interesting if he can actually pull off a working computer using nothing but relays. But even if he doesn’t get beyond the three videos in the playlist already, the channel is definitely worth checking out. We’ve never seen a simpler, clearer explanation of binary logic, and [Clickity Clack]’s relay version of the basic logic gates is a great introduction to the concepts.

Using custom PCBs hosting banks of DPDT relays, he progresses from the basic AND and XOR gates to half adders and full adders, explaining how carry in and carry out works. Everything is modular, so four of his 4-bit adder cards eventually get together to form a 16-bit adder, which we assume will be used to build out a very noisy yet entertaining ALU. We’re looking forward to that and relay implementations of the flip-flops and other elements he’ll need for a full computer.

And pay no mind to our earlier dismissal of non-traditional computer projects. It’s worth checking out this discrete 7400 logic computer and this all-transistor build. They’re impressive too in their own way, if a bit quieter than [Clickety Clack]’s project.

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Early Electromechanical Circuits

In the days before semiconductor diodes, transistors, or even vacuum tubes, mechanical means were used for doing many of the same things. But there’s still plenty of fun to be had in using those mechanical means today, as [Manuel] did recently with his relay computer. This post is a walk through some circuits that used those mechanical solutions before the invention of the more electronic and less mechanical means came along.

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Relay Computing

Recently, [Manuel] did a post on making logic gates out of anything. He mentioned a site about relay logic. While it is true that you can build logic gates using switch logic (that is, two switches in series are an AND gate and two in parallel are an OR gate), it isn’t the only way. If you are wiring a large circuit, there’s some benefit to having regular modules. A lot of computers based on discrete switching elements worked this way: you had a PCB that contained some number of a basic gate (say, a two input NAND gate) and then the logic was all in how you wired them together. And in this context, the SPDT relay was used as a two input multiplexer (or mux).

In case you think the relay should be relegated to the historical curiosity bin, you should know there are still applications where they are the best tool for the job. If you’re not convinced by normal macroscopic relays, there is some work going on to make microscopic relays in ICs. And even if they don’t use relays to do it, some FPGAs use mux-based logic inside.  So it’s worth your time to dig into the past and see how simply switching between two connections can make a computer.

Mux Mania

How do you go from a two input mux to an arbitrary logic gate? Simple, if you paid attention to the banner image. (Or try it interactive). The mux symbols show the inputs to the left, the output to the right and the select input at the bottom. If the select is zero, the “0” input becomes the output. If the select is one, the “1” input routes to the output.

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