How NOT To Make Ground-hugging Fog

Poor [Todd Harrison] spent all of Saturday and Sunday trying to make some ground-hugging fog for his Halloween decor. His fog machine hack turned out to be an utter failure. But he admits it and reports that he still had a lot of fun. Don’t feel bad [Todd], this happens to everyone from time to time. And anyone that has doubts about [Todd’s] skills need not look very far to find out that he does know what he’s doing.

The project started off with a theater-style fog machine. The problem is that this fills a room with a thin foggy-haze that doesn’t take shape outdoors. He wanted that ankle-deep graveyard effect and had seen several examples online that use a fog-machine with a bucked of dry ice. He though he’d just use his own bucket full of regular ice and salt water. Inside the bucket seen above there is a 15′ coil of copper tubing through which the fog machine’s output is passed. On the other side of the bucket there’s a plastic tube that goes to a sheet of plastic meant to distribute the cooled fog.

The problem here is that the fog machine puts out a hot mist. When it hits the ice bath the mist condenses into liquid form and that’s the end of the fog. As he attests in the video after the break, the dry-ice fog hack isn’t pumping out fog. It’s just using the heated steam to pump out carbon-dioxide vapor boiling off of the dry ice.

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Semi-professional Board Assembly For Your Workshop

[Zach Hoeken] has the answer to assembling multiple surface mount PCBs in the home workshop. It’s certainly not for everyone. But if you’ve ever thought of marketing your own small runs he has the equipment and methodology you need.

He had tried using hacked together equipment, but after encountering a range of issues he finds the investment in a few key items saves time and money in the long run. The first is a precision tooling fixture block; that metal plate with a grid of holes that makes up the background of the image above. It comes with machined pegs which fit the holes perfectly, and as you can see, his panel of 16 boards include tooling holes that line up with the fixture. Once in place, a steel solder stencil is aligned with the board using its own tooling holes. The alignment of the stencil and its uniformed thickness ensure that the perfect amount of solder paste is easy to apply with a squeegee. [Zach] hand places his components but he did invest in a proper reflow oven to make the soldering a set and forget process.

A Collection Of Hands To Inspire Your Halloween Animatronics

Jump scares are a lot of fun, but if you want to hold the attention of all those trick-or-treaters we’d suggest a creepy prop. One of the best choices in that category is a ghoulishly lifelike hand. You can draw some inspiration from this roundup of robot hands which Adafruit put together.

We’ve chosen four examples for the image above but there are more to be had than just these. In the upper left there is a laser-cut acrylic hand that actually features some force sensitive resistors on the fingertips to help implement some haptic feedback. This project was inspired by the hand seen in the lower right which uses flex sensors on a glove to control the bot’s movement. If you’re looking for something more realistic the 3D printed parts on the lower left are the best bet. But if you’re looking to put something together by Halloween night the offering in the upper right is the way to go. It’s hacked together using cardboard templates to cut out plastic parts and using polymorph to form joints and brackets.

DIY Pick And Place Builds Boards, Is Awesome

In what can probably be attributed to the pains of placing a lot of SMD components, [gravelrash] built his own home-made pick and place machine.

Instead of being frustrated with tweezers, stereo microscopes, and having an inordinate amount of concentration, [gravelrash] built a pick and place machine from a Chinese CNC router. The build doesn’t use automated feeders for its reels of parts. Instead,[gravelrash] picked up five manual feeders from eBay, allowing his pick and place to hold 25 different reels of components.

There is, of course, a vacuum pump for sucking up SMD parts and a two-axis gantry capable of moving components from reel to board. The software is Mach3, a program normally used with spinning cutters to mill away wood, metal and plastic. [gravelrash] replaced this motor with a few vacuum controlled needles to pick up, move, and drop components onto the board.

While the build may not be as fast as some other pick and place machines we’ve seen, it’s almost as fast as hand-placing components with the added bonus of not tearing your hair out over very tiny parts.

Tip ‘o the hat to [Alexander] for sending this one in.

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QR Clock Is Unreadable By Humans And Computers Alike

The clock is a perfect technology. For just a few dollars, you can buy a digital wristwatch and chronometer able to keep extremely accurate time for years without winding a spring or replacing a battery. Anything ‘improvement’ on the design of a clock only makes it harder to read, a feature exploited by the very 1337 binary clocks we see from time to time. [Ch00f] decided it was time to give way to the march of progress and build a completely unreadable clock. He came up with a QR code clock that is unreadable by humans and cellphones alike.

The hardware is built around nine 8×8 LED matrix panels resulting in a 24 x 24 pixel display, perfect for displaying a 21 pixel square QR code. The LED drivers are a standard multiplexed affair, but this project really shines in the firmware department.

The microcontroller [Ch00f] used – an ATMega328 – is far too small to store the 1440 QR codes for every minute of the day. No, this project would have to dynamically generate QR codes on the fly, not exactly an easy problem.

After looking over the official QR code standard, [Ch00f] wrote a rather large program that turns alphanumeric sequences into QR code. This runs on the microcontroller every minute, generating a new QR code for every minute of the day.

It’s nigh impossible for a human to read a QR code, but [Ch00f] figured he could make his project even less useful. By multiplexing the LEDs at a very low duty cycle [Ch00f] made it impossible for a camera to capture the entire QR code, even though the pattern of pixels is still visible to the human eye. A fabulously useless build that really steps up the game for unreadable clocks.

Video after the break.

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Bora Board Teaches Binary Hardware

If you’re just starting out in your quest to build really cool electronic devices, you’ll find a ton of options ready for the beginner. The Arduino makes toggling pins dead simple, and the Raspi brings the wonders of blinking a LED from the command line down from the gods and into the hands of the common man. These are all software platforms, though, and if you want to learn digital logic with hardware the best option is still a drawer full of 7400-series logic chips.

[Colin O’Flynn] hopes to change this with a beginners board for digital logic hardware design. It’s called the BORA, or Binary explORer boArd, and brings digital logic to a convenient package that is far less frustrating than a breadboard full of logic chips.

The BORA is based around a CPLD – a cousin of the FPGA-powered devices we see from time to time – that allows any student of digital logic to program the device and fill macrocells with NANDs, NORs, and ANDs.

The Xilinx device used in the BORA has about 1600 gates that can be programmed; more than enough to complete all the projects in the online lectures [Colin] has put together. You can check out the documentation for the BORA over on the official site, and the demo video after the break.

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Hackaday Retro Edition: The Macintosh SE/30

In 1988, Apple introduced the Macintosh IIx, an upgrade of the Mac II that included a Motorola 68030 CPU. The IIcx – a compact version of the IIx, also with a 68030 – was introduced in 1989. That same year, product designers at Apple created a more powerful version of the all-in-one Macintosh SE using the same CPU found in the IIx and IIcx. Unfortunately, the naming convention didn’t hold but the Macintosh SE/30 is still the greatest computer Apple will ever build.

Earlier this month, [Greg] sent in a submission for our retro edition successes. A huge mac fan, [Greg] connected his Powerbook Duo to an Ethernet adapter and loaded up our retro edition. [Greg] is back again, this time with an SE/30.

In the three pictures [Greg] sent us (in the gallery after the break), you can see his extremely clean SE/30 booting into System 7 and loading up our retro site. In the third picture, you can see [Greg] playing Bolo, one of the first network-enabled games ever made, and still a very fun waste of time today.

If you’re wondering what makes the SE/30 so great, consider this: the SE/30 is able to address up to 128 MB of RAM. Keep in mind this computer is from an era when one or two Megabytes of RAM would be more than enough to get just about any job done. The SE/30 also made a fabulous server. Even today it would be a capable home media server if it weren’t for its relatively slow networking capabilities and 2 Gigabyte file size (not volume size) limit.

[Greg] has a very cool machine on his hands here, and we’re pleased as punch his SE/30 could make its way over to our retro site.

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