Fail of the Week: Robotic 1950 Mercury Boogies, Won’t Come Back From Dead Man’s Curve

1950 Mercury[Dave] wanted to make an Arduino robot out of a remote-control 1950 Mercury. He removed the RC portion from the car and kept the drive and steering motors. The idea was to use three ultrasonic rangefinders in the grille real estate and move the car forward based on the longest distance detected.

He initially used a Seeed motor controller and some Grove cables soldered to his sensors to power the steering. It went forward, but only forward, and [Dave] decided the motor controller and the car’s steering motor weren’t playing well together.

[Dave] had the idea to use relays instead to both power the motor and determine polarity. Now, the Merc was turning and avoid obstacles about half the time, but it was also getting dinged up from hitting walls. He figured out that his sensor arrangement was making the car turn immediately and decided to give the program information from the wheels with a reed switch and a rare earth magnet. The only problem is that the caliber of magnet required to trip the reed switch is too heavy and strong. [Dave] and has concluded that he simply can’t exercise the kind of control over the car that he needs. and will build his own robot chassis.


2013-09-05-Hackaday-Fail-tips-tileFail of the Week is a Hackaday column which runs every Wednesday. Help keep the fun rolling by writing about your past failures and sending us a link to the story — or sending in links to fail write ups you find in your Internet travels.

The Spooky Nature of Electromagnetic Radiation

image of the face of einstein

Our story begins a little over one hundred years ago in Bern, Switzerland, where a young man employed as a patent clerk went off to work. He took the electric trolley in each day, and each day he would pass an unassuming clock tower. But today was different, it was special. For today he would pose to himself a question – a question whose answer would set forth a fascinating dilemma.

The hands of the clock appeared to move the same no matter if his trolley was stopped or was speeding away from the clock tower. He knew that the electromagnetic radiation which enabled him to see the clock traveled at a finite speed. He also knew that the speed of the light was incredibly great compared to the speed of his trolley. So great that there would not be any noticeable difference in how he saw the hands of the clock move, despite him being at rest or in motion. But what if his trolley was moving at the speed of the reflected light coming from the clock? How would the hands of the clock appear to move? Indeed, they could not. Or if they did, it would not appear so to him. It would appear as if all movement of the clock’s hands had stopped – frozen in an instant of time.  But yet if he looked at the hands of the watch in his pocket, they would appear to move normally. How does one explain the difference between the time of the clock tower versus the time of his watch? And which one was correct?

There was no way for him to know that it would take three years to answer this question. No way for him to know that the answer would eventually lead to the discovery of matter and energy being one and the same. No way to know that he, this underemployed patent clerk making a simple observation, would soon unearth the answer to one of the greatest mysteries that had stumped every mind that came before his – the very nature of time itself.

Now it might have taken Einstein a few years to develop the answer we now know as the Special Theory of Relativity, but it most certainly took him no longer than a few days to realize that Isaac Newton…

must be wrong.

[Read more...]

Retrotechtacular: The CURTA Mechanical Calculator

CURTA mechanical calculatorThe 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.

[Read more...]

Developed on Hackaday: Mooltipass Arduino Shields Compatibility

Mooltipass arduino

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.

[Read more...]

Hacklet 15 – Arcade Fire

15

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!

blackvortex[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!

custom-crtNext 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.

controlpanel[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.

trongame[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!

mikesArcade[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

titanium casting failYou 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.

[Read more...]

Retrotechtacular: There’s More Than One Way to Escape a Submarine

submarine escape title cardAnd 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 COabsorbent.

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

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.

[Read more...]

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