Epoxy Too Thin? Use Wood Flour As A Thixotropic Filler

December 23, 2018 by 27 Comments

The world of glues is wide and varied, and it pays to use the right glue for the job. When [Eric] needed to stick a wide and flat 3D printed mount onto the back of a PCB that had been weatherproofed with an uneven epoxy coating, he needed a gap-filling adhesive that would bond to both surfaces. It seemed like a job for the hot glue gun, but the surface was a bit larger than [Eric] was comfortable using with hot glue for. The larger the surface to be glued, the harder it is to do the whole thing before hot glue cools too much to bond properly.

What [Eric] really wanted to use was a high quality two-part epoxy that he already had on hand, but the stuff was too runny to work properly for this application. His solution was to thicken it with a thixotropic filler, which yields a mixture that is akin to peanut butter: sticky, easily spread to where it’s needed, but otherwise stays in place without dripping or sagging and doesn’t affect bonding.

3D printed pad stuck to back of PCB with thickened epoxy.

Common thixotropic fillers include ground silica or plastic fibers, but [Eric]’s choice was wood flour. Wood flour is really just very fine sawdust, and easily obtained from the bag on his orbital sander. Simply mix up a batch of thin two-part epoxy and stir in some wood flour until the sticky mixture holds its shape. Apply as needed, and allow it to cure.

Thanks to this, [Eric] was able to securely glue a 3D printed pad to the back of his animated LED snowflakes to help mount them in tricky spots. Whether for small projects or huge installations, LEDs, PCBs, and snowflakes are a good combination.

Nintendo Does Sony, Better Than Sony

December 23, 2018 by 23 Comments

Fans of game consoles from the golden era of TV game appliances have been in for a treat over the past couple of years as a slew of official reboots of the stars of the past have reached the market. These so-called “classic” consoles closely follow the styling of the originals, but under the hood they pack modern hardware running an emulator to play a selection of games from ROM. Even better, with a bit of hacking they can run more than just the supplied emulator, people have managed to use them to emulate completely different consoles. Even then, it’s unexpected to find that a PlayStation emulator on a Super Nintendo Classic runs PlayStation games better than the same emulator built in to Sony’s own PlayStation Classic console.

The feat from [8 Bit Flashback] is achieved despite both machines having near-identical hardware specifications based upon the Allwinner R16 system-on-chip. The Nintendo provides smoother action and more responsive controls, making for a far superior gaming experience. How is this achieved? The most significant difference is that the SNES Classic had the RetroArch front end installed upon it, which may have lent some optimisations and tweaks to make the system more efficient.

Readers with an eye for unusual consoles may remember another Nintendo/Sony hybrid, the ill-fated early-1990s prototype SNES with a CD-ROM which was the first machine to bear the name “PlayStation” (or “Play Station” as it was sometimes styled, leading Sony marketeers to be hot on writers using a space between the words a few years later).

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Sanding Seashells By The Seashore

December 22, 2018 by 5 Comments

We all maintain this balancing act between the cool things we want, the money we can spend, and our free time. When the pièce de résistance is a couple of orders of magnitude out of our budget, the only question is, “Do I want to spend the time to build my own?” [Nick Charlton] clearly answered “Yes,” and documented the process for his Nautilus speakers. The speaker design was inspired by Bowers & Wilkins and revised from a previous Thingiverse model which is credited.

The sound or acoustic modeling is not what we want to focus on since the original looks like something out of a sci-fi parody. We want to talk about the smart finishing touches that transform a couple of 3D printed shells into enviable centerpieces. The first, and most apparent is the surface. 3D prints from consumer FDM printers are prone to layer lines, and that aesthetic has ceased to be trendy. Textured paint will cover them nicely and requires minimal elbow grease. Besides sand and shells go together naturally. At first glance, the tripod legs holding these speakers seemed like a classy purchase from an upscale furniture store, but they are, in fact, stained wood and ground-down bolts. Nicely done.

The moral is to work smarter, take pictures, then drop us a line.

Old Game Development IDE Goes FPGA

December 22, 2018 by 3 Comments

If you have a thing for old game development — things like the Atari 2600 or similar period arcade games — you might already know about the 8bitworkshop IDE. There you can develop code in your browser for those platforms. In a recent blog post, the site announced you can now also do FPGA development in the IDE.

According to the site:

Most computers are fast enough to render a game at 60 Hz, which requires simulating Verilog at almost 5 million ticks per second.

To activate Verilog, you need to select the hamburger menu to the top left, select Platform, and then under Hardware, check Verilog. What makes this different from, say, EDA Playground, is that the output can be waveforms or the output to a virtual TV monitor. For example, here’s one of the examples:

The Verilog code is generating horizontal and vertical sync along with an RGB output and the results appear on the monitor to the right. There is a handle at the bottom of the screen. If you drag it up you will see the logic analyzer output. Drag it down and you’ll see the screen again. The examples include an 8-bit and 16-bit CPU, and example games that can even read the mouse.

Honestly, we don’t think anyone would suggest using Verilog to write in-browser games. That isn’t really the point here. However, if you are trying to learn Verilog, it is great fun to be able to produce something other than just abstract waveforms from simulation. The only downside is that to move to a real piece of hardware, you’d need to duplicate the interfaces provided by the IDE. That would not be very hard, and — of course — if you are just using it to learn you can try a different project for the real world.

If you need help getting going in Verilog, we have a series of boot camps that can help. Those tutorials use EDA Playground, but they’d probably work here, too. If you try them in the IDE, be sure to let us know your experience.

Refurbishing A Classic Electrostatic Speaker PSU

December 22, 2018 by 8 Comments

Sometimes a project takes longer than it should to land in the Hackaday in-tray, but when we read about it there’s such gold to be found that it’s worth sharing with you our readers despite its slight lack of freshness. So it is with [Andrew Back]’s refurbishment of his Quad electrostatic speaker system power supply, it may have been published back in August but the glimpse it gives us into these legendary audio components is fascinating.

The inner workings of an electrostatic loudspeaker
The inner workings of an electrostatic loudspeaker

An electrostatic speaker is in effect a capacitor with a very large surface area, of which one plate is a flexible membrane suspended between two pieces of acoustically transparent mesh that form the other plates. A very high DC bias voltage in the multiple kilovolts region is applied across the capacitor, and the audio is superimposed upon it at a peak-to-peak voltage of somewhere under a kilovolt through a step-up transformer from the audio amplifier. There are some refinements such as that the audio is fed as a push-pull signal to the opposing mesh plates and that there are bass and treble panels with different thickness membranes, but these speakers are otherwise surprisingly simple devices.

The problem with [Andrew]’s speakers became apparent when he took a high voltage probe to them, one speaker delivered 3 kV from its power supply while the other delivered only 1 kV. Each supply took the form of a mains transformer and a voltage multiplier board, so from there it became a case of replacing the aged diodes and capacitors with modern equivalents before applying an insulating layer for safety.

Electrostatic speakers are no stranger to Hackaday, we’ve taken an in-depth look at them in the past. You may also find some of our colleague [Steven Dufresne]’s writing on the matter to be of interest, on measuring high voltages, and his experience wrangling high voltage.

Get Your Tweets Without Looking

December 22, 2018 by 5 Comments

Head-mounted displays range from cumbersome to glass-hole-ish. Smart watches have their niche, but they still take your eyes away from whatever you are doing, like driving. Voice assistants can read to you, but they require a speaker that everyone else in the car has to listen to, or a headset that blocks out important sound. Ignoring incoming messages is out of the question so the answer may be to use a different sense than vision. A joint project between Facebook Inc. and the Massachusetts Institute of Technology have a solution which uses the somatosensory reception of your forearm.

A similar idea came across our desk years ago and seemed promising, but it is hard to sell something that is more difficult than the current technique, even if it is advantageous in the long run. In 2013, a wearer had his or her back covered in vibrator motors, and it acted like the haptic version of a spectrum analyzer. Now, the vibrators have been reduced in number to fit under a sleeve by utilizing patterns. It is being developed for people with hearing or vision impairment but what drivers aren’t impaired while looking at their phones?

Patterns are what really set this version apart. Rather than relaying a discrete note on a finger, or a range of values across the back, the 39 English phenomes are given a unique sequence of vibrations which is enough to encode any word. A phenome phoneme is the smallest distinct unit of speech. The video below shows how those phonemes are translated to haptic feedback. Hopefully, we can send tweets without using our hands or mouths to upgrade to complete telepathy.

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Clever Wedges That Will Increase Your PCB Assembly Yield

December 22, 2018 by 22 Comments

If there’s one thing that will bring down the yield of your PCB assembly, it’s your solder paste. Put too much on, and you’ll get bridged leads. If you don’t put enough on, that pad might not make good contact. [ScalarElectric] has an amazing trick that’s sure to astonish and astound. Just use wedges and you’ll get better yield with fine-pitched components.

The trick here is to define the cream/solder paste layer of each package as a wedge on each pad instead of the usual rectangle. This gives a few benefits, the largest being the increased gap between paste shapes. You’re also getting a reduction in the total amount of paste applied, and a subsequent improvement in yield. (Reportedly, we’d love to see some data on this.)

PCB design tools usually have a way to alter the size of the cream/solder paste layer of a design, and indeed one option is to simply shrink the size of the paste layer elements. The trick to the wedges is increasing the total distance between solderpaste blobs while keeping the total amount of solderpaste high. This technique can be used down to 0.5mm pitch parts, and everything works like a charm.

While this is a little outside of our wheelhouse here at Hackaday — it is, after all, a novel use of existing tools that is mostly applicable to electronic design and production. [Ed Note: Sarcasm.] You can check out a few pics of this technique in the slideshow below. If you test this technique out, be sure to let us know how it went!