Powdered Glue Activates When Squished

November 15, 2015 by Al Williams 37 Comments

Sometimes a hack needs something more than duct tape. Cyanoacrylate glue is great, if you don’t mind sticking your fingers together. But it doesn’t stick to everything, nor does it fill gaps. Epoxy is strong, but isn’t nearly as convenient. The point is, one type of glue doesn’t fit every situation, and that’s why you have to keep a lot of options. [Syuji Fujii] of Japan’s Osaka Institute of Technology (and his colleagues) have a new option: a glue that goes on dry and sticks when squished.

According to New Scientist, the researchers rolled spheres of a latex liquid in a layer of calcium-carbonate nanoparticles. The resulting spheres are a few millimeters across and pour easily. When put under pressure for a few seconds, the nanoparticles are pushed inside, and the sticky liquid contacts the surface. The source paper is also available if you want to read the gory details. Or you can cut right to the video below to see it in action.

If you don’t think glue is a good hacking material, you don’t know [Kevin Dady]. You can even glue wires if you really hate soldering, although we’d rather solder.

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How To Build Beautiful Enclosures From FR4 — Aka PCBs

June 3, 2015 by Voja Antonic 90 Comments

Most hobbyists say that it is easier to build a functional prototype of an electronic device, than to make the enclosure for it. You could say that there are a lot of ready-made enclosures on the market, but they are never exactly what you need. You could also use a 3D printer to build a custom enclosure, but high-end 3D printers are too expensive, and the cheaper ones produce housings which are often not robust enough, and also require a lot of additional treatment.

Another way is to build the enclosure out of FR4, a material which is commonly used in PCB production. Such enclosures are low-cost, with thin walls but yet very strong, nice looking, pleasant to the touch and have excellent thermal and moisture stability. FR4 offers some more possibilities – efficient wiring with no wires inside the housing, integrated UHF or SHF antennas or RFID coils, capacitive switches, electrical shielding, selective semi-transparency, water or air tightness, and even integration of complex mechanical assemblies.

Here I shall explain the process of building those “magic” enclosures. It is based on nearly fifty years of personal experience and more than a hundred enclosures, built for most of my projects. Here are two examples – this case for a hardware password manager is just a few centimeters long, while the other one (protective transportation cover for my son’s synthesizer) measures 125cm (about 49 inches), and yet both of them are strong enough to withstand a grown man standing on top of them.

The global approach is simple – you take the sheet of single-sided copper clad FR4, cut it and solder the parts together. That sounds simple, but there are a lot of details which should be met if you want to get top results. Please read about them carefully. You might be tempted to skip some of the steps described here, but if you do so, you will most likely end up being disappointed with the results.

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A Automated Optical Inspection machine, inspecting the USB Armory board

Meet The Machines That Build Complex PCBs

March 31, 2015 by Eric Evenchick 12 Comments

You can etch a simple PCB at home with a few chemicals and some patience. However, once you get to multilayer boards, you’re going to want to pay someone to do the dirty work.

The folks behind the USB Armory project visited the factories that build their 6 layer PCB and assemble their final product. Then they posted a full walkthrough of the machines used in the manufacturing process.

The boards start out as layers of copper laminates. Each one is etched by applying a film, using a laser to print the design from a Gerber file, and etching away the unwanted copper in a solution. Then the copper and fibreglass prepreg sandwich is bonded together with epoxy and a big press.

Bonded boards then get drilled for vias, run through plating and solder mask processes and finally plated using an Electroless Nickel Immersion Gold (ENIG) process to give them that shiny gold finish. These completed boards are shipped off to another company, where a pick and place followed by reflow soldering mounts all the components to the board. An X-Ray is used to verify that the BGA parts are soldered correctly.

The walkthrough gives a detailed explanation of the process. It shows us the machines that create products we rely on daily, but never get to see.

Penny And Paper Clip Heat Sinks

March 8, 2015 by Anool Mahidharia 45 Comments

A bunch of audio heads over at the Head-Fi forum were discussing handy and quick heat sinking methods, leading to much speculation and conjecture. This finally prompted [tangentsoft] to take matters in his own hands and run some tests on DIY Heat Sinks.

The question that sparked this debate was if a paper clip is a good enough heat sink to be used for a TO220 package. Some folks suggested copper pennies (old ones minted 1981 and earlier – the new ones are zinc with copper plating and won’t help much). [tangentsoft] built a jig to test six LM317 regulators in constant current mode set to 0.125A and 2w dissipation. The six configurations were a paper clip, a single penny bolted to the regulator, a regular Aavid TO220 heat sink, a set of 4 pennies bolted, a single penny epoxy glued and finally a single penny soldered directly to the regulator.

The results were pretty interesting. The paper clip scored better than any of the single pennies! The quad-penny and the Aavid heat sink fared above all the other configurations, and almost at par with each other. [tangentsoft] posts his review of each configurations performance and also provides details of his test method, in case someone else wants to replicate his tests to corroborate the results. He tested each configuration independently for one hour, gathering just over 10000 readings for each setup. Other nearby heat sources were turned off, and he placed strategic barriers around the test circuit to isolate it from the effects of other cooling / heating sources. He even removed himself from the test area and monitored his data logging remotely from another room. When he noticed a couple of suspect deviations, he restarted the test.

[tangentsoft] put all the data through Mathematica and plotted his results for analysis, available at this link [pdf, 2.8MB]. So the next time you want to heat sink a regulator for cheap, just hunt for Clippy in your box of office supplies. Do remember that these methods will work for only a couple of watts dissipation. If you would like to cast and build your own heat sinks out of aluminum, check out this post about DIY Aluminum heat sink casting. And if you need help calculating heat sink parameters, jump to 12:00 minutes in this video from [Dave]’s EEVBlog episode on Dummy loads and heat sinks.

Thanks to [Greg] for sending in this tip.

Using Surface Mount Devices On A Breadboard

July 25, 2014 by Brian Benchoff 17 Comments

[Czar] was working on a project with the Raspberry Pi using the MCP3008 analog to digital converter. The surface mount SOIC version of this chip was slightly cheaper, and there’s always a way to make that work (Portuguese, Google Translation). How [Czar] did it is fairly impressive, as it’s a bit more flexible for breadboard designs than a through-hole version, and done correctly, is an extremely sturdy hack.

A few new leads needed to be soldered onto the SOIC package, and for this [Czar] chose jumper wires. This makes each pin easy to plug into a solderless breadboard, and since [Czar] was extremely clever, all the wires for power, ground, analog, and SPI are color coded.

Simply soldering a few jumper wires onto a chip won’t last for very long. To solve this problem, [Czar] potted the entire chip and its connections with hot glue. Probably not the best solution, and a heavy-duty epoxy would have been better, but the current build is more than enough to stand up to the relatively minor abuse it will receive on the workbench.

Rebuilding A Custom IC Saves HP Pulse Generator

April 21, 2014 by Adam Fabio 38 Comments

Rebuilding an HP Custom IC [Matthew] got himself into a real pickle. It all started when he was troubleshooting a broken Hewlett Packard 8007A pulse generator. While trying to desolder one of the integrated circuits, [Matthew] accidentally cracked it. Unfortunately, the chip was a custom HP Pulse shaper IC – not an easy part to source by any means. That broken chip began a 5 year mission: to explore strange new repair methods. To seek out new life for that HP 8007A. To boldy fix what no one had fixed before.

[Matthew’s] first repair attempt was to build a drop in replacement for the HP chip. He took a look at the block diagram, and realized the chip was just some simple logic gates. He built his version with a small PCB and Fairchild TinyLogic gates. Unfortunately, the TinyLogic series is fast CMOS, while HP’s original chip used Emitter-coupled Logic (ECL). Thanks to the wildly different voltage levels of the two logic families, this design had no chance of working.

Five years later, [Matthew] was going to school at MIT, and had access to a wire bonding machine. He rebuilt the package using some epoxy, and managed to re-run the various bond wires. While everything looked promising, this attempt was also a failure. After all that work, the chip was blown.

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Developed On Hackaday: The Top PCB Dilemna

April 12, 2014 by Mathieu Stephan 15 Comments

The Hackaday community offline password keeper is slowly coming together. A few days ago we received the top PCB for Olivier’s design (shown above). If you look at the picture below, you may see the problem we discovered when opening our package: the soldermask was the wrong color! Given the board is meant to be placed behind a tinted acrylic panel, this was quite a problem…

After using some spray paint, we managed to get to the point shown in the bottom left of the picture. The next task was to find the best way to illuminate the input interface with reverse mount LEDs. Using a CNC mill we machined openings (top right PCB) but also removed some epoxy on both PCB’s sides, thinking it would provide a better light diffusion. We then wrote part of the Mooltipass PWM code and took these pictures:

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