A Pair Of Projects To Scare The Trick-or-Treaters

October 29, 2014 by Bryan Cockfield No comments

The countdown is on! There’s only a few days left until Halloween, and if you’re still looking for something to spice up the experience for the kids heading to your door, [MagicWolfi] has just what you need. He’s put together two motion-sensing projects that are sure to startle any trick-or-treater.

The first project is a chain of LED-lit pumpkins that are activated by a motion sensor. A set of inverters paired with RC delay lines light up the pumpkins sequentially. They are arranged almost like a strand of Christmas lights and are powered by AA batteries, so in theory they could be expanded to make a strand as long as needed. The project was inspired by a motion-sensing dress and works pretty well as a Halloween decoration!

[MagicWolfi] is pairing the LED pumpkins with his second project which uses another motion sensor to play scary sound effects. Dubbed the Scare-o-Matic, this device uses a 45-millimeter speaker connected to a SparkFun microSD audio module to produce the scary sound effects. Each time it is triggered it plays a different sound from the list. There are videos and schematics for each of these projects on the project sites if you are interested in recreating any of these before Friday!

Water Softener Level Detector Keeps You Out Of Trouble With Wife

October 29, 2014 by Rich Bremer 81 Comments

Some households have water supplies that contain higher than desired levels of minerals. This condition is called hard water. There is nothing harmful about hard water but it does leave mineral deposits on pipes and appliances and makes cleaning a little bit more difficult. The solution is to have a water softener system which is basically a tank filled with salt that the household water passes through. This tank has to be refilled about every month and [David] was catching a little flak from his wife because he kept forgetting to fill it. He then set out to do what any great husband would do and built a Water Softener Monitor that reports the quantity of salt in the basement tank up to the living quarters.

[David] started thinking that he should test the salinity of the water to determine if salt needed to be added but after thinking about it for a while decided against it because any metal in that salty water would surely corrode. A non-contact approach would be to use an IR distance sensor mounted to the top of the tank and measure the distance to the pile of salt that slowly lowers as it dissolves into the water. In this case, he used a Sharp GP2D12 that can measure accurately from 10 to 80cm.

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A Proof Of Concept Flash Cart For The WonderSwan

October 28, 2014 by Brian Benchoff 22 Comments

Unless you’ve been to Japan or are fairly deep into the retro game collecting, you’ve probably never heard of the WonderSwan. It’s a handheld console, released after the Game Boy Color was beginning to show its age, and a bit before the introduction of the Game Boy Advance. It sold rather well in the only country it was released in, the game library is somewhat impressive, and there are quite a few homebrew games. Actually running these homebrew games is a challenge, though: each WonderSwan has a memory controller that maps the game ROM into the CPU’s memory. Without knowing how this controller chip works, the only way to run a homebrew cartridge is to turn on the machine with a real cart, go to the system menu, and swap the carts out. It turns out there’s a better solution, that includes programming CPLDs and looking at the output of a logic analyzer.

The first step towards [Godzil]’s efforts to create a Flash cart for the WonderSwan is to figure out the pinout of the cartridge connector – something that isn’t well documented for a system without a homebrew hardware scene. This was done in the usual way; with a lot of ribbon cable and patience This only provided an incomplete picture of how the WonderSwan interfaced with its carts, but after digging up an official development board, [Godzil] was able to make sense of all the signals.

After building a breakout board for the cartridge port, [Godzil] connected a DE0 Nano FPGA board and looked at all the signals. With just a little bit of VHDL, the memory controller could be reverse engineered and reimplemented. [Godzil] has his proof of concept working – video below – and the next part of his project will be to turn this into a proper Flash cart.

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This Home-Made 6-Axis Robotic Arm Is Quite The Looker

October 28, 2014 by Sarah Petkus 41 Comments

With a background in software engineering, [Kris Temmerman] decided to make a physical demonstration of his knowledge in the form of a six axis robotic arm… the final product is a delicious display of mechanical eye candy.

Built from mostly aluminum stock, [Kris] machined the bulk of his parts with a CNC mill which he picked up for cheap from China. These custom pieces coupled with some hefty stepper motors ensure the arm’s accuracy as it twists freely and slides along the gantry it’s mounted to. Though the majority of the arm is metal, the hand at the end of his robot was built with 3D printed parts and can be switched out with the future attachments [Kris] plans to design. This classic gripper piece is driven separately with its own Arduino brain controlling the individual servos in the fingers.

Each finger includes some load bearing sensors which [Kris] harvested from an old scale so that the gripper can tell whether or not it has a hold of an object without crushing it. To orchestrate the robot’s movement, he wrote some nice looking software in C++ which visualizes the inverse kinematics at work in each point of articulation. For the sake of demonstrating his creation in action, he whipped up a basic demo that can locate and move colored blocks laid at random on a surface. A small camera mounted on the hand determines the orientation of the blocks relative to the machine so that the wrist can rotate itself in the proper alignment in order to pick them up.

[Kris] documented the build of his robot in a fascinating speed video which includes footage of the finished arm in action at the end:

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Make Flexible PCBs With Your 3D Printer

October 28, 2014 by Adam Fabio 25 Comments

The last few years have seen great strides in budget printed circuit board manufacturing. These days you can have boards made in a week for only a few dollars a square inch. Flexible PCBs still tend to be rather expensive though. [Mikey77] is changing that by making flex circuits at home with his 3D printer. [Mikey77] utilized one of the properties of Ninjaflex Thermoplastic Elastomer (TPE) filament – it sticks to bare copper!

The TPE filament acts as an etch resist, similar to methods using laser printer toner. For a substrate, [Mikey77] lists 3 options:

.004″ thick “Scissor cut” copper clad board from Electronics Goldmine

.002″ thick pure copper polyester taffeta fabric from lessEMF.com

<.001″ Pyralux material from Adafruit, which is one of the materials used to make professional flex PCBs.

A bit of spray adhesive will hold the Flex PCB down on the printer’s bed. The only issue is convincing the printer to print a few thousandths of an inch higher than the actual bed level. Rather than change the home position on his Z axis, [Mikey77] used AutoDesk 123D to create 3D PCB designs. Each of his .stl files has a “spacer bar”, which sits at the bed level. The actual tracks to be printed are in the air a few thousandths of an inch above the bed – exactly the thickness of the substrate material. The printer prints the spacer bar on the bed, then raises its Z height and prints on the flexible PCB material. We’re sure that forcing the printer to print in mid-air like this would cause some printer software to throw errors, but the system worked for [Mikey77] and his Makerbot.

Once the designs have been printed, the boards are etched with standard etching solutions such as ferric chloride. Be careful though – these thin substrates can etch much faster than regular PCB.

Retrotechtacular: Fire Control Computers In Navy Ships

October 28, 2014 by Kristina Panos 29 Comments

Here is a two-part Navy training film from 1953 that describes the inner workings of mechanical fire control computers. It covers seven mechanisms: shafts, gears, cams, differentials, component solvers, integrators, and multipliers, and does so in the well-executed fashion typical of the era.

Fire control systems depend on many factors that occur simultaneously, not the least of which are own ship’s speed and course, distance to a target, bearing, the target’s speed and course if not stationary, initial shell velocity, and wind speed and direction.

The mechanisms are introduced with a rack and pinion demonstration in two dimensions. Principally speaking, a shaft carries a value based on revolutions. From this, a system can be geared at different ratios.

Cams take this idea further, transferring a regular motion such as rotation to an irregular motion. They do so using a working surface as input and a follower as output. We are shown how cams change rotary motion to linear motion. While the simplest example is limited to a single revolution, additional revolutions can be obtained by extending the working surface. This is usually done with a ball in a groove.

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New To The Store: Bulbdial Clock And Free Shipping Option

October 28, 2014 by Mike Szczys 22 Comments

New to the Hackaday Store today is the Bulbdial Clock by Evil Mad Scientist Laboratories. I’ve had my eye on this kit for years and finally pulled the trigger after visiting [Lenore] and [Windell] at their shop a few weeks back. Assembling the beautifully-engineered kit was a delight, and I have a handful of hacks I’d like to try out — some of which I mentioned in the product description.

Free shipping based on order price

We always listen to what the Hackaday community has to say. After receiving several requests for better international shipping prices we came up with a way to ease the pain for orders no matter where they are headed. All domestic orders totaling $25 or more now receive free shipping. All international orders totaling $50 or more now receive free shipping.

Is there anything else you’d like to see different about the store? How about a hackable product you think we should stock? We’re listening via the store contact form.