Misc Hacks

4179 Articles

Data Mining And Saving Money With Octopart’s Historical Pricing

July 6, 2012 by 6 Comments

[Greg Shikhman] is at Octopart this summer as a software development intern. In between the time he’s spending getting coffee for the other devs, he came up with historical pricing for thousands of components available at Octopart

There’s a lot of cool data out there, like this bit of pricing info for a 555 timer. We’re guessing a few people were out of stock of 555s around the end of May, explaining why they were selling (well, available for) $1.68 a piece. If you’re trying to source components, it might be worth your while to check out Octopart’s historical price index. Buying a PIC microcontroller last August was a roll of the dice; in one day the price changed from $5 to just over $2.

With all this data, it’s even possible to data mine for real life events unrelated to shipping and stocking issues. Japanese manufacturer Renesas was hit pretty hard by last year’s earthquake, and this shows up in the historical prices for one of their microcontrollers. Not bad for an intern’s project.

Anti-Sanecraft ARTillery Cannon Is Farm Boy Engineering At Its Finest

July 5, 2012 by 13 Comments

The term “just enough knowledge to be dangerous” comes immediately to mind with this one. The official description is “a large scale pan and tilt propane Flame Effect” but that hardly does this thing justice. The Anti-Sanecraft ARTillery Cannon is a three-barrel fire cannon that can move around like its namesake and launch massive propane bursts from two 1″ diameter barrels. The third barrel is somewhat special, it is constructed of stronger steel and can be pre-fed with oxygen to create one massive intense propane-O2 mixed fire burst.

The trick about the whole thing is that when oxygen and propane are mixed it is a highly volatile and dangerous thing, in a closed space they classify as an explosive. Instead oxygen is filled directly into the open ended barrel separately and is allowed to sit until propane fires it out. This mixes the two fuels in the open air where it is safer and far away from any bystanders. We would not suggest you try this at all ever, as the effect was so loud during the Transformus festival that neighbors, miles away from the large festival ground, were complaining  about rattling windows. This is the kind of place where several thousand watt sound systems are pushed near the red with no issue, just to give a bit of a comparison.

We can’t seem to find a video of this thing in action either [Beyond Joy] just posted a video of this crazy contraption in action (without the O2 effect), check it out after the jump! Don’t forget to check the facebook photo album for all the NPT pipe fitting action, (warning some images of the phallic controls are very mildly NSFW).

Photo Credit: [Bert Reed Photography]

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The Cool Kids All File Their Resistors For Accuracy

July 5, 2012 by 43 Comments

Here’s a tip to keep in your back pocket, you can use a metal file to adjust your resistors. [Gareth] shows off this technique in the video after the break. A metal file is literally all that you need to do some fine tuning. Just make sure you’re starting off with a carbon film resistor as this will not work with the metal film variety.

His example shows a 10k resistor which is reading just 9.92k on his multimeter. But he needs precisely 10k. After getting through the protective layer he makes just a couple of passes with a small file, each time adding about 20 Ohms of resistance. Now he does mention that excessive deep cuts can hurt the power rating of the resistor. But this certainly isn’t damaging it if done correctly. It turns out this is how they are tuned at the factory.

One possible use he mentions is trimming the balance on a hacked servo motor.

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A Guide For Laying Out 4+ Layer PCBs

June 29, 2012 by 21 Comments

Learning to lay out a printed circuit board takes some time. But after you’ve churned out a few it’s really pretty easy. If you find yourself at that point it may be time to learn about more complicated board fabrication. We think a good primer is this multi-layer PCB layout guide which [Rik te Winkel] recently put together. It’s one of the results of his internship experience.

One of the major differences with boards that have more than two layers is the ability to alter what layers are actually connected by vias. Vias are plated holes through the substrate that connect different layers of copper. In the case of a 2-layer board these just go right through and connect the top to the bottom. But as you can see above, there are additional choices when it comes to multi-layer boards. #1 is a through via connecting all of the layers. #2 is a blind via; it stops part way through the board. And #3 is a buried via; it connects internal layers but cannot be seen from either side.

The guide is aimed at Eagle CAD. To use more than two layers you’ll have to purchase a license. But we think the concepts can easily be translated to other PCB layout software like Kicad.

Dollar Store Terminator Replica

June 28, 2012 by 16 Comments

Okay, now we think [James] is just on a mission to see what he can build using the dollar store as his parts bin. This is the nearly finished replica of the cyborg skeleton from the Terminator franchise. It’s made mostly from things that cost $0.99.

Actually we’ve got that a bit wrong. [James] is really shopping at the £0.99 store but the concept is basically the same. He’s already shown us that he’s a pro at this with the arc reactor replica we recently saw from him. This time around a set of speakers donate their enclosures to build up the spinal column supporting the skull. Fittingly these are glued together using a hot glue gun from the store. The sides of the skull are carefully crafted from a set of four plastic bowls. The jaw comes together thanks to the corners of a plastic box’s lid. And finally the majority of the face is from a golden skull costume mask. Spray it all grey and pop in some LEDs for the eyes and he’s done it! He show’s off his final creation in the video after the break.

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How About A Nice Game Of Nixie Chess?

June 27, 2012 by 12 Comments

[Tony] sent in a Nixie tube chess set he’s been working on, and we’re just floored with the quality of this build. The chess pieces glow without any visible wires, the board is extremely elegant with touches of gilding and brass, and extremely well designed using (mostly) materials and components contemporary to the old Russian Nixie tubes.

Instead of numeric Nixies, [Tony] chose IN-7 and IN-7A tubes originally made to display scientific symbols such as A, V, and ~. To power the these tubes, [Tony] used 64 air-core transformers underneath each square on the chess board, allowing these Nixie tubes to be powered just like an induction charger.

Even though his blog posts are a little thin on details, we’ve got to hand it to [Tony] for an amazing build. He says there will be a kit available that includes a gigantic PCB, but we wouldn’t hazard a guess as to how much that will cost.

You can check out a pair of videos of the Nixie chess set in action after the break.

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Knut Logs Data, Sends It To Your Email

June 24, 2012 by 7 Comments

[Richard] and [Jay] needed a WiFi connected data logger for remotely monitored aquariums. After working diligently for three years, they’re finally finished. While the Knut was originally designed to keep tabs on a few huge aquariums, it’s more than capable to log all sorts of data and send those sensor readings to your email address.

Knut is a small WiFi enabled device replete with a few plugs for temperature, humidity, accelerometer, and other sensors. All this data goes directly into the memory of Knut, and when the memory is full the data is sent to an email address. As a bonus, there’s also an iDevice app (Android and Windows coming soon) to parse the generated .CSV file and display the results on an iPhone

The Knut may be a touch expensive for our tastes, but if you’re looking for an off-the-shelf solution for sending alerts, logging data, or just reading a few sensors via WiFi, Knut may be just the ticket.

[Richard] and [Jay] put together a demo video showing off the capabilities and operation of the Knut app; check that out after the break.

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