Homemade EDM Can Cut Through Difficult Materials Like Magnets With Ease

August 7, 2016 by 32 Comments

Many years ago [ScorchWorks] built an electrical-discharge machining tool (EDM) and recently decided to write about it. And there’s a video embedded after the break.

The build is based on the designs described in the book “Build an EDM” by Robert Langolois. An EDM works by creating lots of little electrical discharges between an electrode in the desired shape and a material underneath a dielectric solvent bath. This dissolves the material exactly where the operator would like it dissolved. It is one of the most precise and gentle machining operations possible.

His EDM is built mostly out of found parts. The power supply is a microwave oven transformer rewired with 18 gauge wire to drop the voltage to sixty volts instead of the oven’s original boost to 1.5kV.  The power resistor comes from a dryer element robbed from a unit sitting beside the road. The control board was etched using a hand traced schematic on the copper with a Sharpie.

The linear motion element are two square brass tubes, one sliding inside the other. A stepper motor slowly drives the electrode into the part. Coolant is pumped through the electrode which is held by a little 3D printed part.

The EDM works well, and he has a few example parts showing its ability to perform difficult cuts. Things such as a hole through a razor blade., a small hole through a very small piece of thick steel, and even a hole through a magnet.

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Vegapin: A Beautiful Virtual Pinball Machine

August 7, 2016 by 7 Comments

One click on the wrong YouTube link, and one sleepless night after being introduced to virtual pinball, and [Sascha Rossier], aka Swiss hip-hop rapper [Der Lügner], was at work on his own design. You can watch the plans, and the build progress on [Sascha]’s project diary (in German, translated here). The awesome case, huge monitor serving as the playfield, bump and tilt sensors make this a droolworthy device.

We also learned how to say “greebles” in Swiss-German: “greebles“. And there are greebles galore in this build. [Sascha]’s 3D printer was working overtime churning out not only fan ducts for the computer that lives inside the case, but also dia-de-los-muertos themed foot brackets and all sorts of loudspeaker covers and dinosaur accoutrements. This is clearly a labor of love. (And [Sascha] wrote us back about the date in the name: it’s when he and his girlfriend met 20 years ago, playing pinball nonetheless!)

Head off to [Sascha]’s website and check it out. All of the details are there, from the mechanical design to the part selection. This is probably the most elaborate virtual pinball build we’ve seen, but it’s not the only one. Heck, we’ve even seen a virtual machine built into a real pinball machine’s case. But never before have we seen one with so darn many greebles.

Jump In When The Water Is Just Right With A Wireless Swimming Pool Thermometer

August 7, 2016 by 21 Comments

[David]’s family acquired a swimming pool. While it’s not his favorite activity in the world, every now and then he’ll indulge in the blue plastic bin full of water occupying previously pristine land in his backyard.

As he says, cool beer is pleasant, but cool water tends to put a damper on the experience. Rather than do something pedestrian like touch the water himself to discover its temperature; he saw an opportunity for a fun little project in a wireless temperature monitor.

The heart of the device is a Telecom Design TD1208 which runs on the French SigFox network. For a small fee any device on the network can send up to 140 12byte packets of data a day. Not a lot, but certainly acceptable for the Microchip MCP9700 temperature sensor it uses. He got the board up and running, and even made his own custom helical coil antenna.

The case was 3D printed out of PLA. It’s a tiered cylindrical bobber. The wider top section floats on the water and the base acts as a ballast, holding the battery and sensor.  The bobber is powered by a combination of  a questionable Chinese lithium battery, charging circuit, and solar panel. [Dave] was keen to point out that the battery is, technically, water cooled.

He wrapped up the code for the bobber and used SigFox’s SDK to build a nice web interface. Now, when the rare mood strikes him, he can remain inside if the conditions aren’t right for a swim.

Refurbishing Six Commodore 64s In Parallel

August 7, 2016 by 12 Comments

[Drygol] found himself with six Commodore 64’s in various states of disrepair. Because batch work is often more efficient, he detailed the process of restoring all of them in parallel in this one-, two-, three-part series.

The first step was to whiten the cases. Old cases turn yellow from the degradation of the fire retardant additives in the plastic. The proven method to fix this is with a paste called Retr0bright. [Drygol] used hair bleaching paste which is very similar. The cases came out nicely whitened from their treatment.

Next he repaired the keyboard PCB and whitened the keys as well. Drinking was involved, but it all came out okay. The circuit boards were cleaned and inspected. There were a few corroded spots, broken chips, and bad solder joints to be repaired. A few common mods were also installed.

In the final part of the series two of the C64s have SD cards installed into them. A few interesting fixes were done to repair broken plastics. Lastly the two worst cases were painted. In the end [Drygol] found himself with six perfectly working and attractive C64s. Who know’s what he’ll do with them, but we all know that was not the point.

Single Motor Lets This Robot Do The Worm

August 7, 2016 by 17 Comments

With more and more research in the field of autonomous robotics, new methods of locomotion are coming on the scene at a rapid pace. Forget wheels and tracks, forget bi-, quad-, hexa- and octopods, and forget fancy rolling BB-8 clones. If you want to get a mini robot moving, maybe you should teach it to do the worm.

Neither the Gizmodo article nor the abstract of [David Zarrouk]’s paper gives too many details on the construction of this vermiform robot, but there are some clues to be gleaned from the video below. At the 1:41 mark we see the secret of the design – a long corkscrew in the center of the 3D-printed linkages.
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Hackaday Prize Entry: The Strength Of 3D Printed Parts

August 6, 2016 by 16 Comments

[Sam Barrett] is doing something that is sorely needed. He’s doing real materials research on FDM parts.

There’s nothing wrong with the rough experiments like hanging a 1 L bottle of water from the end of a rectangular test print to compare strengths. We also have our rules-of-thumb, like expecting the print to perform at 30% of injection molded strength. But these experiments are primitive and the guidelines are based on hearsay. Like early metallurgy or engineering; 3D printing is full of made-up stuff.

What [Sam] has done here is really amazing. He’s produced a model of a printed ABS part and experimentally verified it to behave close enough to the real thing. He’s also set a method for testing and proposed a new set of questions. If it couldn’t be better, he also included his full research notebook. Make sure to read the FDMProperties-report (PDF) in the files section of Hackaday.io.

Sam finally answered a question we've had of what it looks like when the printer over extrudes.
Sam finally answered a question we’ve had of what it looks like when the printer over extrudes.

If research like this is being done elsewhere, it’s either internal to a large 3D printer manufacturer, or it’s behind a paywall so thorough only the Russians can help a regular peasant get through to them. Anyone with access to a materials testing lab can continue the work (looking at you every single engineering student who reads this site) and begin to help everyone achieve an understanding of 3D printed parts that could lead to some really cool stuff one day.

Weird CPU

August 6, 2016 by 24 Comments

How many instructions does [agp.cooper’s] computer have? Just one. How many strip boards does it use? Apparently, 41 five 41-track boards. While being one shy from the answer to life, it is still a lot of boards for a single instruction. The high board count is due to the use of 1970’s vintage ICs including TTL parts, 2114 RAM chips, and 74S571 PROMs.

There are several different architectures for single instruction computers and [agp’s] uses what is technically at TTA (transfer-triggered architecture). That is, the one instruction is a move and the destination or source of the move determines the operation. For example, the Wierd CPU (that’s the name of it) has a P and Q register. If you load those registers and then the ADD register will contain the sum of the two numbers.

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