Retrotechtacular: The CURTA Mechanical Calculator

September 16, 2014 by Kristina Panos 39 Comments

The CURTA mechanical calculator literally saved its inventor’s life. [Curt Herzstark] had been working on the calculator in the 1930s until the Nazis forced him to focus on building other tools for the German army. He was taken by the Nazis in 1943 and ended up in Buchenwald concentration camp. There, he told the officers about his plans for the CURTA. They were impressed and interested enough to let him continue work on it so they could present it as a gift to the Führer.

This four-banger pepper mill can also perform square root calculation with some finessing. To add two numbers together, each must be entered on the digit setting sliders and sent to the result counter around the top by moving the crank clockwise for one full rotation. Subtraction is as easy as pulling out the crank until the red indicator appears. The CURTA performs subtraction using nine’s complement arithmetic. Multiplication and division are possible through successive additions and subtractions and use of the powers of ten carriage, which is the top knurled portion.

Operation of the CURTA is based on [Gottfried Leibniz]’s stepped cylinder design. A cylinder with cogs of increasing lengths drives a toothed gear up and down a shaft. [Herzstark]’s design interleaves a normal set of cogs for addition with a nine’s complement set. When the crank is pulled out to reveal the red subtraction indicator, the drum is switching between the two sets.

Several helper mechanisms are in place to enhance the interface. The user is prevented from ever turning the crank counter-clockwise. The crank mechanism provides tactile feedback at the end of each full rotation. There is also a lock that disallows switching between addition and subtraction while turning the crank—switching is only possible with the crank in the home position. There is a turns counter on the top which can be set to increment or decrement.

You may recall seeing Hackaday alum [Jeremy Cook]’s 2012 post about the CURTA which we linked to. A great deal of information about the CURTA and a couple of different simulators are available at curta.org. Make the jump to see an in-depth demonstration of the inner workings of a CURTA Type I using the YACS CURTA simulator.

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Developed On Hackaday: Mooltipass Arduino Shields Compatibility

September 16, 2014 by Mathieu Stephan 15 Comments

Some of our dear readers may already have an infallible system to remember different complex passwords for the different websites they visit daily. This is why they may have not been following the offline password keeper that the Hackaday community is building.

The Mooltipass has a characteristic that may regain their interest: it is possible to connect Arduino shields to it. In the video embedded below you can see the Arduino conversion process our development team imagined a few months back. The operation simply consists in using a knife to remove plastic bits on top of standard Arduino headers. We also embedded a few use cases with their respective sketches that may be downloaded from our official GitHub repository.

As with stacking several shields, a little tweaking may be required to keep the functionalities from both the Mooltipass and the connected shield. We therefore strongly welcome Arduino enthusiasts to let us know what they think of our setup.

In the meantime, you may want to subscribe to our official Google Group to stay informed of the Mooltipass launch date.

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Hacklet 15 – Arcade Fire

September 12, 2014 by Adam Fabio 8 Comments

This week’s Hacklet is dedicated to arcade games. The arcade parlors of the 80’s and early 90’s may have given way to today’s consoles and PC games, but the classic stand-up arcade cabinet lives on! Plenty of hackers have restored old arcade cabinets, or even built their own. We’re going to take a look at some of the best arcade game-related hacks on Hackaday.io!

[Brayden] starts things off with his Raspberry Pi Vintage Arcade. The Black Vortex is a tabletop arcade cabinet using a Raspberry Pi, an old monitor, and some nice carpentry skills. Black Vortex uses a Raspberry Pi B+. The extra GPIO pins make interfacing buttons and joystick switches easy. On the software side, [Brayden] is using the popular PiMame (now PiPlay) flavor of Linux built for gaming and emulation. Black Vortex’s shell is plywood. [Brayden] used a pocket hole jig to build a sturdy, cabinet without extra support blocks. A stain finish really works on this one!

Next up, [fredkono] blows our minds with the Arcade XY Monitor From Scratch. [fredkono] repairs classic Atari vector game PCBs. He needed a test monitor for his lab. The original Amplifone and WG6100 color XY monitors used in games like Tempest and Star Wars are becoming rather rare. Not a problem, as [fredkono] is building his own. Much like the WG6100, [fredkono] started with a standard color TV CRT. He removed and rewound the yoke for vector operation. The TV’s electronics were replaced with [fredkono’s] own deflection amplifier PCBs. [fredkono] was sure to include the all- important spot killer circuit, which shuts down the electron guns before a spot can burn-in the CRT.

[Rhys] keeps things rolling with a pair of projects dedicated to arcade controls. His TI Launchpad Arcade Control to USB Interface contains instructions and code to use a Texas Instruments Tiva C launchpad as a USB interface for arcade controls. [Rhys] puts all that to good use in his Arcade Control Panel. The control panel features MAME buttons, as well as the standard 2 player fighting game button layout. He finished off his panel with some slick graphics featuring red and blue dragons.

[Sarah and Raymond] hosted a Tron:Legacy release party back in 2010. An epic arcade movie calls for an epic arcade game, or in this case, games. 16 table top arcades to be exact. All 16 machines were built in just 6 days. 8 of the machines ran Armegatron Advanced, a networked version of the classic Tron lightcycle game. The others ran a mix of classic games like PacMan or modern bullet hell shooters like Tou-Hou. The cabinets were built from expanded PVC with wood blocks as a support structure. [Sarah and Raymond] custom painted each cabinet with UV black light paint. We love the custom artwork on their personal signature machines!

[Mike] takes us back to the 80’s with Just Another Arcade Machine. Under the hood, this machine uses the standard Raspberry Pi and PiMame (now PiPlay) suite. [Mike] even added a trackball so he could play Centipede. What makes this arcade special is the cabinet. [Mike] found an old wardrobe with that perfect 80’s style metallic strip cladding. [Mike] removed the cladding, and cut up the chipboard frame. He re-assembled things into a stand-up arcade cabinet that looks like it came right out of Sears’ Electronics department in 1985.

Ok folks, that’s it for another episode of The Hacklet. As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!

Fail Of The Week: This Inanimate Titanium Rod

September 11, 2014 by Kristina Panos 69 Comments

You saw [Chris] cast aluminium on the cheap using Kinetic Sand a few weeks ago, didn’t you? He recently got his meaty hands on some titanium through the magic of modern transactional methods and was bowled over by its strength, hardness, and poor heat transfer.

He thought he would cast it into a nice, strong bottle opener. As you can probably guess, that didn’t go so well. First off, it wasn’t easy to saw through the thin rod. Once he did get it split in twain, it was surprisingly cool to the touch except at the tip. This is nasty foreshadowing, no?

[Chris] takes a moment to help us absorb the gravity of what he’s about to do, which of course is to send several hundred amps through that poor rod using a DC arc welder. Special precautions are necessary due to the reaction between oxygen and heated titanium. His trusty graphite crucible is grounded to the bottom of a big aluminium tub, and a cozy blanket of argon from a TIG welder will shield the titanium from burnination.

Well . . . the titanium didn’t melt. Furthermore, the crucible is toast. On the up side, vise-enabled cross-sectional examination of the crucible proved that there was still gold in them there walls.

Do you have any (constructive, on-topic) suggestions for [Chris]? Let him know below.

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Retrotechtacular: There’s More Than One Way To Escape A Submarine

September 9, 2014 by Kristina Panos 29 Comments

And this 1953 United States Navy training film describes two ways to do so: collective escape via rescue chamber, and individual escape using SEAs.

The film first follows a fellow named [Baxter] and his men in the aft torpedo room. His sub has failed to surface as scheduled. There are no officers present at the time of distress, so [Baxter, Torpedoman First] is in charge. His first directive is that [Johnson] extinguish his Chesterfield. There’ll be time enough for smoking on the rescue ship, [Johnson].

[Baxter] releases a marker buoy because it is daytime and the weather is fair. Had other conditions prevailed, [Baxter] would send up flares and bang on the hull to provide a sonic beacon for rescuers. Next, he checks the forward compartments. If they are clear, he leaves the hatches open to give his men more air. He checks the air purity and engages [Brooklyn] to pull down some CO₂absorbent.

[Baxter] and his men will be okay for a while. They have plenty of drinking water, food, juice, supplemental oxygen, and CO₂absorbent. Their best move is to take it easy and wait for the rescue chamber. That way, they’ll avoid drowning, exposure, and CO₂poisoning.

Elsewhere in the forward torpedo chamber, there’s a chlorine leak and it can’t be stopped. These nameless sailors have to work quickly to escape the noxious gas. First, they pass around the SEAs and turn them into respirators. Soda lime will filter out the chlorine gas from their lungs and eyes. They too will release a marker buoy, but the first order of business is to move to the escape trunk.

Communicating through gestures, the lead man assigns three men to break out the life raft. The men move to the trunk with the buoy, raft, ascending line, and a divers’ knife. They also take a battle lantern, hand tools, and spare SEAs, but leave their shoes behind. After equalizing the pressure in the trunk, they can get going on their escape. They open the hatch, float the buoy, and tie it off. Now the raft can be floated up the buoy line. Since they are 100 feet down, they send a man every ten seconds up the buoy line and he is to move approximately one foot per second. First man to surface inflates the raft, and Bob’s your uncle. Now, they just have to prevent sunburn and tell stories until the rescue ship finds them.

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Hacklet 14 – Hacks Around The House

September 5, 2014 by Adam Fabio 25 Comments

In this weeks Hacklet we’re looking at household hacks. Not necessarily globally connected home automation hacks, but task specific hacks that we want in our lives yesterday!

We’ve all had it happen, you’re burning the midnight oil on a project when you realize it’s garbage night. The mad dash to collect empty anti-static bags, last night’s Chinese food, and the rest of the trash before actually venturing outside in the dark.

[Mehmet-cileli] doesn’t have to deal with any of that, thanks to My Bins, his automated trash and recycling can moving system. Normally the bins are stationed near the house. Each garbage night, the system springs into action. The cans and their platform pivots 90 degrees. The entire system then rolls along a track to the curb. Once the cans have been collected, everything rolls back ready for more trash. We just hope [Mehmet’s] garbage men are nice enough to put the bins back on their platform!

Next we have the perfect cup of tea. [Marcel] kept forgetting his tea while it was steeping. After ending up with ink a few times, he built this Automatic Tea Timer. A button starts the timer, and after a few minutes, the tea bag is automatically lifted and a light illuminates to let you know your tea is ready. [Marcel] used a ~~Raspberry Pi~~ ~~Arduino~~ ~~555~~ simple R-C timer circuit to create his delay. The lift arm is a discarded hard drive read arm. The light bulb limits current through the voice coils.

[Juan Sandu] always has veggies with his Smart Small Greenhouse. [Juan] has created a desktop sized greenhouse that gives plants what they crave. No, not Brawndo, we’re talking water, warmth, and light. An Arduino Uno uses sensors to monitor humidity, temperature, light, and moisture. Based upon one of two pre-set plant types, the system determines when to water, turn on lights, or even power up a fan to keep temperatures plant friendly. [Juan] is still working on his greenhouse, but his code is already up on Github.

Next up is [nerwal] with his entry in The Hackaday Prize, GrillUp. GrillUp is a remote grill temperature monitoring system with a cooling spray. Up to 6 food grade thermometers provide GrillUp with its temperature data. If things are getting a bit too hot, Grillup cools the situation down by spraying water, beer, or your favorite marinade. The system is controlled over Bluetooth Low Energy from an android smart phone. A laser pointer helps to aim the water spray. Once the cooling zones are set up, the system runs automatically. It even has a sprinkler mode, where it sprays everything down.

Every hacker’s house needs some Sci-fi mood lights, right? [spetku and maehem] round out this weeks Hacklet with their Fifth Element Stone Mood Lighting. Originally an entry in the Hackaday Sci-fi contest, these mood lights are based on the elemental stones in everyone’s favorite Bruce Willis movie. The lights are 3D printed in sections which stack over foamboard cores. The actual light comes from a trio of RGB LEDs. LED control is from the same brain board which controls the team’s Robot Army. The lights are designed to open up just like the ones in the movie, though fire, earth, wind, and water are not required. The servos [spetku and maehem] selected weren’t quite up to the task, but they mention this will be remedied in a future revision.

That’s a wrap for this week’s Hacklet. As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!

Ask Hackaday: Who Wants An All DC House?

September 4, 2014 by Will Sweatman 268 Comments

Sometimes when working on a righteous hack, we get goosebumps while watching our code execute faster than we could ever possibly comprehend. Seeing the pixels of the LCD come alive, hearing the chatter of relays and the hum of fans…it’s an amazing thing what electricity can do. And it is equally amazing when you realize that it all started one hundred and thirty five years ago, when [Thomas Edison] changed the world forever with the first practical electric light bulb.

That bulb was lit by a Direct Current – the same thing that runs the computer you’re reading this article on. The same thing that runs many of the hacks you read about here on Hack a Day, and almost all electronic devices in your house. But somewhere in the mix must exist a device that changes the Alternating Current from your wall outlet to the needed DC. Why? Why is it that we transport electricity as AC only to convert it to DC in our homes? You might answer:

“This argument was played out in the War of Currents back in the 1880’s.”

Indeed, it was. But that was a long time ago. Technology has changed. Changed so much to the point that the arguments in the War of Currents might no longer be valid. Join us after the break, where we rehash these arguments, and explore the feasibility of an all DC environment.

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