Advances In Flat-Pack PCBs

November 28, 2018 by Brian Benchoff 44 Comments

Right now, we’ve got artistic PCBs, we’ve got #badgelife, and we have reverse-mounted LEDs that shine through the fiberglass substrate. All of this is great for PCBs that are functional works of art. Artists, though, need to keep pushing boundaries and the next step is obviously a PCB that doesn’t look like it has any components at all. We’re not quite there yet, but [Stephan] sent in a project that’s the closest we’ve seen yet. It’s a PCB where all the components are contained within the board itself. A 2D PCB, if you will.

[Stephen]’s project is somewhat simple as far as a #badgelife project goes. It’s a Christmas ornament, powered by two coin cells, hosting an ATTiny25 and blinking two dozen LEDs via Charlieplexing. The PCB was made in KiCAD, with some help from Inkscape and Gimp. So far, so good.

The trick is mounting all the components in this project so they don’t poke out above the surface of the board. This is done by milling a rectangular hole where every part should go and adding castellated pads to one side of the hole. The parts are then soldered in one at a time against these castellated pads, so the thickness of the completed, populated board is just the thickness of the PCB.

The parts used in this project are standard jellybean parts, but there are a few ways to improve the implementation of this project. The LEDs are standard 0805s, but side-emitting LEDs do exist. If you’d like to take this idea further, it could be possible to create a sandwich of PCBs, with the middle layer full of holes for components. These layers of PCBs can then be soldered or epoxied together to make a PCB that actually does something, but doesn’t look like it does. This technique is done in extremely high-end PCBs, but it’s expensive as all get out.

Still, this is a great example of what can be done with standard PCB processes and boards ordered from a random fab house. It also makes for a great Christmas ornament and pushes the boundaries of what can be done with PCB art.

A Sub-$1000, Non-X86 Motherboard

November 26, 2018 by Brian Benchoff 101 Comments

If you’re building a computer, your options are nearly limitless. You can get a motherboard with red LEDs, with blue LEDs, green LEDs, or if you’re feeling spendy, RGB LEDs. You can get custom-milled heat spreaders in any shape you want, as long as it’s angular and screams ‘gamer’. If you want a motherboard that doesn’t use x86 — either AMD or Intel — you’re kind of out of luck. Either it doesn’t exist, or it’s going to cost a small fortune.

Raptor Engineering have just released a motherboard that isn’t x86 and doesn’t cost as much as a cheap car. The Blackbird mainboard is designed for an IBM Power9 CPU and it only costs $800. Add in a four-core CPU and the total cost comes out to about $1200. Add in some ECC RAM and you’re still under two grand. Building with a non-x86 CPU has never been cheaper. This is a significant change from earlier releases from Raptor Engineering, where just the motherboard cost $3700.

The Blackbird mainboard features dual DDR4 ECC DIMM slots, one PCI Express 4.0 x16 slot, one PCI Express 4.0 x8 slot, dual Gigabit Ethernet ports, 4 x SATA 3.0 ports, 4 x USB 3.0 ports, 1 x USB 2.0 port, and an HDMI display output.

The only reason you would build a Power9-based computer is simply to get around the black box that has become Intel and AMD CPUs. No one is really sure what’s going on in the Intel Management Engine, AMD has similar black boxes littered around. However, using a Power9 CPU has a secure boot mode and provided your computer is physically secure, you’re more or less assured you’re running your firmware and your kernel and your userspace apps. It’s security for the security-minded. RISC architecture is going to change everything.

Applied Science Rolls An Electroluminescent Controller

November 26, 2018 by Brian Benchoff 30 Comments

After LEDs and TFTs and OLEDs and liquid crystals, there’s another display technology that doesn’t get a lot of attention. Electroluminescent displays have been around for ages, and there still aren’t a whole lot of applications for them. That might change soon, because Applied Science a.k.a. [Ben Krasnow] figured out an easy way to build EL displays on anything, and created a simple circuit that’s capable of driving video on a remarkable blue phosphor EL display.

For this build, [Ben] is using a specialty product from Lumilor consisting of a copper-ish conductive base layer, a clear dielectric, the ‘lumicolor’ phosphor, and a clear conductive top coat. All of these layers are applied with an airbrush, and the patterns are made with a desktop vinyl cutter. This is an entire system designed to put electroluminescent displays on motorcycle gas tanks and to have doors that go like *this* and glow. That said, the system isn’t very dependent on the substrate, and [Ben] has had successful experiments in creating EL displays on plastic sheets, 3D printed parts, and even paper.

Compared to previous (and ongoing) efforts to create EL displays such as [Fran]’s recreation of the Apollo DSKY, the Lumilor system seems extraordinarily easy and clean. Current efforts as with [Fran]’s example are using a silkscreen process, which is a mess no matter how you look at it and can’t be applied to non-flat surfaces.

But EL displays are more than just putting a few layers of chemicals on a substrate — you need to drive these displays with high-frequency, high-voltage AC. For this, [Ben] designed a multi-channel electroluminescent driver based on the Adafruit Trinket M0, two LT3468 ICs to generate a high voltage, and either a an HV507 or HV513 to drive 8 or 64 channels.

With the ability to create EL displays and drive 64 channels, there really was only one thing to do: a 32×32 display. Even seeing a few lines scan across a 32×32 EL display is magical, but it’s got another trick up its sleeve: it also plays a low-resolution video of Never Gonna Give You Up.

This isn’t a video to be missed, check it out below.

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Watch The Low-Cost Mechatronics Lab Dispense Candy, Sort Cups

November 26, 2018 by Donald Papp 5 Comments

A lot can be done with simple motors and linear motion when they are mated to the right mechanical design and control systems. Teaching these principles is the goal behind the LCMT (Low Cost Mechatronics Trainer) which is intended primarily as an educational tool. The LCMT takes a “learn by doing” approach to teach a variety of principles by creating a system that takes a cup from a hopper, fills it with candy from a dispenser, then sorts the cups based on color, all done by using the proper combinations of relatively simple systems.

The Low Cost Mechatronics Trainer can be built for under $1,000 and is the wonderful work of a team from the Anne Arundel Community College in Maryland, USA. The LCMT is clearly no one-off project; there are complete CAD files and build documentation on the site, as well as a complete lab guide for educators.

A demo video of the assembled system is embedded below, with a walkthrough done by [Tim Callinan]. It’s worth a watch to see how cleanly designed the system is, and the visual learners among you may learn a thing or two just by watching the system go through its motions.

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Put That DLP Printer To Use Making PCBs

November 24, 2018 by Tom Nardi 38 Comments

Now that these DLP printers are cheaper and more widely available, we’re starting to see hackers poking around the edge of the envelope to see what else the machines are capable of. [Electronoobs] recently got his hands on a couple of these printers, and thought he would do some experiments with using them for PCB production.

Rather than extruding molten plastic, these printers use light to cure resin layer-by-layer. In theory if the printer is good enough to cure the light-activated resin for a high resolution print, it should be able to do much the same thing with photosensitive PCBs.

Unfortunately, getting an STL out of a PCB design program takes a few intermediary steps. In the video after the break, [Electronoobs] shows his workflow that takes his design from EasyADA and turning it into a three dimensional object the DLP printer will understand. He does this with Blender and it looks pretty straightforward, but in the past we’ve seen people do similar tricks with Inkscape if that’s more your style.

Once you’ve grafted another dimension onto your PCB design, you may need to scale it to the appropriate size. [Electronoobs] notes that his STL for a 60 mm wide PCB came out of Blender as less than 2 mm wide, so you might need to break out the dreaded mathematics to find the appropriate scale value. Once the dimensions look good, you can load this file up into the printer as you would any normal print.

On the printer side of things, [Electronoobs] manually laminates UV photoresist film onto some copper clad boards with an iron, but you could skip this step and buy pre-sensitized boards as well. In any event, you drop the board where the UV resin normally goes, press the print button, and wait about ten minutes. That should give it enough time to expose the board, and you then proceed with the normal washing and acid bath process that hackers have been doing since time immemorial.

As [Electronoobs] shows, the results are quite impressive. While this still won’t make it any easier for you to do double-sided PCBs in the home lab, it looks like a very compelling method for producing even SMD boards with relative ease. This isn’t the first time somebody has tried using a DLP printer to run off some PCBs, but now that the technology has matured a bit it looks like it’s finally becoming practical.

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Energy Sipping Neodymium Sphere Keeps On Spinning

November 23, 2018 by Tom Nardi 16 Comments

At this point we’re sure you are aware, but around these parts we don’t deduct points for projects which we can’t immediately see a practical application for. We don’t make it our business to say what is and isn’t worth your time as an individual hacker. If you got a kick out of it, great. Learned something? Even better. If you did both of those things and took the time to document it, well that’s precisely the business we’re in.

So when [Science Toolbar] sent in this project which documents the construction of an exceptionally energy efficient spinning neodymium sphere, we knew it was our kind of thing. In the documentation it’s referred to as a motor, though it doesn’t appear to have the torque to do any useful work. But still, if it can spin continuously off of the power provided by a calculator-style photovoltaic cell, it’s still a neat trick.

But how does it work? It starts by cracking open one of those little solar powered toys; the ones that wave or dance around as soon as any light hits the panel in their base. As [Science Toolbar] explains, inside these seemingly magical little gadgets is a capacitor and the classic black epoxy blob that contains an oscillator circuit. A charge is built up in the capacitor and dumped into a coil at roughly 1 Hz, which provides just enough of a push to get the mechanism going.

In the video after the break, [Science Toolbar] demonstrates how you can take those internals and pair it with a much larger coil. Rather than prompting a little sunflower or hula girl to do its thing, the coil in this version provides the motive force for getting the neodymium sphere spinning. To help things along, they’re even using a junk box zero friction magnetic bearing made up of a wood screw and a magnetized screwdriver tip.

It’s an interesting example of how a tiny charge can be built up over time, and with a nice enough enclosure this will make for a pretty cool desk toy. We’ve previously seen teardowns of similar toys, which revealed a surprising amount of complexity inside that little epoxy blob. No word on whether or not the version [Science Toolbar] cannibalized was quite so clever, however.

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Many Ways To Drive A Small Motor

November 19, 2018 by Kerry Scharfglass 17 Comments

Tiny motors used for haptic feedback and vibration come in a variety of shapes and sizes. The most familiar is the “eccentric rotating mass” (ERM) variety which just spins an imbalanced weight on a small motor and comes packaged in two form factors. The classic is the pager “pager motor” which just looks like a tiny, adorable motor and the squat cylindrical “pancake style”. ERMs are simple to use but provide imprecise response when compared to their new-age cousin the “linear resonant actuator”. Unlike the motor in an ERM, LRAs are typically an enclosed mass on a spring placed near a coil which pushes the mass back and forth. The name LRA might not be familiar but Apple’s branded implementation, the Taptic Engine, might be a little more recognisable.

[Precision Microdrives] is a vendor of these sorts of devices who happens to have a pleasantly approachable set of application notes covering any conceivable related topic. A great place to start is this primer on ways to drive motors with constant voltage in a battery powered environment. It starts with the most simple option (a voltage divider, duh) and works through a few other options through using an LDO or controller.

If you’re thinking about adding haptics to a project and are wondering what kind of actuator to use (see: the top of this post) AB-028 is a great resource. It has a thorough discussion on the different options available and considerations for mounting location, PCB attachment, drive modes, and more. Digging around their site yields some other interesting documents too like this one on mounting to fabric and other flexible surfaces. Or this one on choosing PWM frequencies.