Turning 3D Prints Into Aluminum Castings

September 25, 2012 by Brian Benchoff 54 Comments

[Jeshua] needed a laser head attachment for a 5×10 foot CNC machine he’s working on. Because he has a 3D printer, [Jeshua] could easily print a laser mount and attach it to his CNC gantry, but that wouldn’t look very professional. Instead of decorating his gigantic machine with brightly colored plastic, he decided for a more industrial look by casting a laser head in aluminum using a 3D printed master.

[Jeshua] designed two parts for his laser cutter in OpenSCAD and printed them out on his 3D printer. A few bits of foam insulation were glued on to act as sprues, and an investment mold was made out of 1 part Plaster of Paris and 1 part playground sand.

After the mold had cured, [Jeshua] put is mold in a coffee can furnace to burn out the wax and foam. These hollow molds were placed in sand and the crucible loaded up with aluminum scrap.

The finished laser head fit his CNC machine perfectly – no small feat, considering [Jeshua] needed to take in to account how much the aluminum would contract after cooling. Not bad for one day’s work.

UV LEDs Expose PCBs, Gives You A Tan

September 24, 2012 by Brian Benchoff 30 Comments

Among the projects that define electronic design, a UV exposure box is right up at the top of the list. These boxes shine UV light on a work piece and are used for everything from exposing photosensitive PCBs to erasing EPROMs. [carlolog] decided to build his own and ended up with a fairly impressive array of ultraviolet LEDs perfect for making PCBs or tanning the back of your hand.

One important thing to remember when making large arrays of LEDs is current consumption and power needed to light the device up. [carlolog] naive assessment of how much power would be required used a 12 volt supply with 135 LEDs and 135 resistors, wasting a lot of energy and producing 24 Watts of heat.

Of course this power consumption can be reduced by putting a few LEDs in series, so [carlolog] wired 3 LEDs together with a 150Ω resistor. This array requires just over 11 Watts and consumes less than 1 Amp; perfect for a desktop UV box.

The enclosure for the box was crafted out of three Ikea photo frames, and a small timer circuit powered by an ATmega8 was added. Now whenever [carlolog] needs to wipe an EPROM, he can put the chip in the box, set the timer, and walk away.

A very nice build, but when dealing with a lot of UV we must remind our readers: do not look into the UV array with your remaining eye.

Etching Brass And Copper With The Etchinator

September 16, 2012 by Brian Benchoff 16 Comments

If you’re in to making your own PCBs at home, you know the trials of etching copper clad boards. It’s slow, even if you’re gently rocking your etch tank or even using an aquarium pump to agitate your etching solution. [cunning_fellow] over on Instructables has the solution to your etching problems, and can even produce printmaking plates, jewelry, photochemically machine small parts, and make small brass logos of your second favorite website.

The Etchinator is a spray etcher, so instead of submerging a copper clad board into a vat of ferric or cupric chloride, etching solution is sprayed onto the board. We’ve seen this technique before, but previous builds use pumps to spray the etching solution and cost a bundle. [cunning_fellow]’s Etchinator doesn’t used pumps; it’s driven by two cordless drill motors sucking up etching solution through a hollow tube.

The basic idea behind the build is sticking a vertical PVC pipe in a box with etching solution. Mount an impeller in the bottom of the tube, drill many small holes in the side of the tube, and spin it with a motor up top. The solution is sucked up the tube, sprayed out the sides, and falls back down into the reservoir. Put a masked off copper board in the tank and Bob’s your uncle.

Not only did [cunning_fellow] come up with an awesome PCB etching solution, but the same machine can be used for etching brass plate for printmaking, and even photoetching brass sheets for model planes, trains, and automobiles. The quality is really amazing; the Instructables robot above was etched out of 0.7 mm thick brass, with an etch depth of 0.35 mm with only 0.05 mm of undercut. A very awesome build that is already on our ‘to build’ project list.

Augmented Reality Welding Mask

September 11, 2012 by Mike Szczys 53 Comments

There are so many good ideas crammed into this project its hard for us to believe this isn’t already widely used for critical welding applications. Traditional welding masks simply filter out light to protect the welder’s eyes. This mask doesn’t have a window in it at all. Instead, the mask includes two cameras on the outside and two LCD screens on the inside. It filters light by processing the video which lends itself to that grab-bag of features we mentioned earlier.

Possibly the best of the system is its ability to selectively filter the brightness of the weld. What this means is that areas outside of the welding arc appear at a normal brightness level, whereas before they would have been greatly dimmed. A demonstration of augmented reality is also shown, where a computer monitors the welding surface, giving the welder a target to follow and measuring the distance between the weld and the filament. The video mentions that an FPGA would be well suited for the image processing, making us think this could be produced at a reasonable cost. After all, they already use X-ray machines for some welds, we’d bet a set of these helmets could be supplied to a crew at a similar cost.

[via Reddit]

Beautifully Crafted Geiger Counter A Must If You Live In A Hot Zone

September 8, 2012 by Mike Szczys 10 Comments

Have a little class when you’re screening for radioactive particles. You can follow the example which [Moustachenator] has set with this gorgeous Geiger counter case.

The business end includes the same Geiger tube we see in all of these projects, but he took the time to solder together a tidy circuit board and housed it in an acrylic tube. it connects to the base unit using a springy telephone handset cord. The laser cut walnut enclosure offers plenty of room for the ATX power supply hidden inside. This feeds the Arduino which runs the system, and provides a powerful source for the Nixie tubes which serve as the display. The attention to detail when it came time to assemble the case is what lends an antique look to the project, even though everything was built from the ground up. Check out the video after the break to see a brief demonstration.

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Scratch-built RFID Reader

September 7, 2012 by Mike Szczys 11 Comments

We never bought an RFID reader because it seems too simple to be all that much fun. But [Abdullah] really caught our eye with his latest project. It’s an RFID reader built from discrete parts, and that’s an adventure we can get behind!

His write-up dives right into the theory of the device. He wrapped his own coil, which measure about one microhenry, then shares an equation used to calculate the appropriate capacitor pair for it. This is fed by a 125 kHz oscillator and works as the most basic reader. In practice this needs more components for rock-solid operation and he quickly moves to a marginally more complicated circuit which still does exactly the same thing.

He is now able to detect RFID tag data by reading this circuit with an oscilloscope. But the signal is very very weak. The rest of the post focuses on how to best utilize an OpAmp to increase signal quality and on/off time.

If you’re looking to recreate his reader [Abdullah] included a Kicad schematic and board layout.

Saving The ISS By Hacking A Toothbrush

September 7, 2012 by Caleb Kraft 32 Comments

We absolutely love these stories of hacker ingenuity saving peoples lives. In this case, it was aboard the ISS, and the item being hacked was a toothbrush.

The story is as follows. Some equipment failed, as space junk tends to do, and the astronauts found themselves needing to do some repairs. Upon inspection, they couldn’t remove some modules due to an accumulation of “space dust” around some bolts. This was especially troubling as the unit in question was something that was supposed to route power from some of the solar arrays to the ISS. Even more troubling is that another unit failed while they were assessing the situation.

Realizing they had to act fast so as not to lose too much power to function, they cobbled together some tools to allow them to clean out the access ports and remove the units for repair. A task that sounds like an easy solution here on earth proved to be life threatening in space. Eventually though, their makeshift tools came to the rescue and they were able to repair and restore power.