Hackaday Links: May 26, 2019

Thinkpads are great, especially the old ones. You find a T420, and you can have a battery hanging off the back, a battery in the optical drive bay, and for some old Thinkpads, there’s a gigantic ‘slice’ battery that doubles the thickness of your laptop. Here’s the most batteries in a Thinkpad ever, with the requisite reddit post. It’s 27 cells, with an all-up capacity of 212 Watt-hours. There are two interesting takeaways from the discussion here. First, this may, technically, be allowed on a commercial flight. The FAA limit is 100 Watt-hours per battery, and the Ultrabay is a second battery. You’re allowed two additional, removable batteries on a carry on, and this is removable and reconfigurable into some form that the TSA should allow it on a plane. Of course no TSA agent is going to allow this on a plane so that really doesn’t matter. Secondly, the creator of this Frankenpad had an argument if Hatsune Miku is anime or not. Because, yeah, of course the guy with a Thinkpad covered in Monster energy drink stickers and two dozen batteries glued on is going to have an opinion of Miku being anime or not. That’s just the way the world works.

Prices for vintage computers are now absurd. The best example I can call upon is expansion cards for the Macintosh SE/30, and for this computer you have a few choice cards that have historically commanded a few hundred dollars on eBay. The Micron XCEED Color 30 Video Card, particularly, is a special bit of computer paraphernalia that allows for grayscale on the internal monitor. One of these just sold for two grand. That’s not all, either: a CPU accelerator just sold for $1200. These prices are double what they were just a few years ago. We’re getting to the point where a project to reverse engineer and produce clones of these special cards may make financial sense.

The biggest news in consumer electronics this week is the Playdate. It’s a pocket game console that has a crank. Does the crank do anything? No, except that it has a rotary encoder, so this can nominally be used for games. It will cost $150, and there are zero details on the hardware other than the industrial design was done by Teenage Engineering. There’s WiFi, and games will be delivered wireless on a weekly basis. A hundred thousand people are on the wait list to buy this.

If you want a pick and place in your garage workshop, there aren’t many options. There’s a Neoden for about ten grand, but nothing cheaper or smaller. The Boarditto is a two thousand dollar pick and place machine that fits comfortably on your desk. It has automatic tape feeders, a vision system, and for the most part it looks like what you’d expect a small, desktop pick and place machine to be. That’s all the information for now, with the pre-order units shipping in December 2019.

Vacuum Tubes: Shipping Through EBay Now Challenging?

There is disquiet in the world of vacuum electronics, that something as simple as shipping a vacuum tube could now be very difficult to achieve. It’s a concern expressed among other places in a video by [Guitologist] that we’ve included below, and includes tales of vacuum tubes being impounded as either dangerous to ship, or not allowed to be shipped across international borders.

Upon investigation it appears that the common thread in all the stories lies with eBay’s Global Shipping Program, the centralised shipping service operated by the online auction giant. We reached out to eBay’s press office on the subject but have yet to receive a reply. It’s best to ask someone who ships a lot of tubes for comment when you have a tube shipping story, so we also had a conversation with TC Tubes. They’re a small company dealing in tubes, and as you might imagine they ship a lot of them (Their website is likely to detain you for a while if you are a tube-head). [Chelsea] from TC Tubes told us that they have encountered no regulatory barriers to tube shipping, and that their only bad experience has been yet again with eBay’s Global Shipping Program.

So it seems there is no cause for panic if you ship tubes, CE marking or RoHS rules haven’t come for your EL34s and your 6550s. Ebay have evidently got some kind of issue with tubes in their shipping operation, and perhaps you should ship by other means if you wish to avoid your tubes going astray. The consensus here among the Hackaday crew is that it could be as simple as uninformed employees not being aware of what tubes are because they aren’t as common as they used to be. After all, with over a hundred years of history behind them it’s not as though any potential issues with their shipping haven’t been comprehensively explored.

We’d still be interested to hear from eBay on the matter though, if they would care to comment.

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Fail Of The Week: Cheap Chips Cause Chaos

We all know the old saw: if it’s too good to be true, it probably is. But nowhere does this rule seem to break down as regularly as when we order parts. Banggood, AliExpress, and eBay are flooded with parts ready to be magically transported across the globe to our doorsteps, all at prices that seem to defy the laws of economics.

Most of these transactions go off without a hitch and we get exactly what we need to complete our Next Cool Thing. But it’s not always so smooth, as [Kerry Wong] recently discovered with an eBay order that resulted in some suspicious chips. [Kerry] ordered the AD633 analog multiplier chips as a follow-up to his recent Lorenz Attractor X-Y recorder project, where he used an Arduino to generate the chaotic butterfly’s data set as a demo for the vintage instrument. Challenged in the comments to do it again in analog, [Kerry] did his homework and found a circuit to make it happen. The needed multipliers were $10 a pop on DigiKey, so he sourced cheaper chips from eBay. The $2 chips seemed legit, with the Analog Devices logo and everything, but the circuit didn’t work. [Kerry]’s diagnosis in the video below is interesting, and it’s clear that the chips are fakes. Caveat emptor.

Here’s hoping that [Kerry] sources good chips soon and regales us with a successful build. Until then, what are your experiences with cheap chips? Have you been burned by overseas or domestic suppliers before? Does any single supplier seem like a better bet to you, or is it all hit or miss? Sound off in the comments below.

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Drop-in Controller For EBay K40 Laser Engraver Gets Results

[Paul de Groot] wrote in to let us know about a drop-in controller replacement he designed for those economical K40 laser engravers that are everywhere on eBay. With the replacement controller, greatly improved engraving results are possible along with a simplified toolchain. Trade in the proprietary software and that clunky security dongle for Inkscape and a couple of plugins! [Paul] felt that the work he accomplished was too good to keep to himself, and is considering a small production run.

Laser engravers are in many ways not particularly complex devices; a motion controller moves the head in x and y, and the laser is turned on or off when needed. But of course, the devil is in the details and there can be a surprising amount of stuff between having a design on your screen and getting it cut or engraved in the machine. Designing in Inkscape, exporting to DXF, importing the DXF to proprietary software (which requires a USB security dongle to run), cleaning up any DXF import glitches, then finally cutting the job isn’t unusual. And engraving an image with varying shades and complex dithering? The hardware may be capable, but the stock software and controller? Not so much. It’s easy to see why projects to replace the proprietary controllers and software with open-source solutions have grown.

Cheap laser engravers may come with proprietary controllers and software, but they don’t need to stay that way. Other efforts we have seen in this area include LaserWeb, which provides a browser-based interface to a variety of open-source motion controllers like Grbl or Smoothieware. And if you’re considering a laser engraver, take a few minutes to learn from the mistakes of other people.

The Long Tail Of DIY Electronics

These are the Golden Years of electronics hacking. The home DIY hacker can get their hands on virtually any part that he or she could desire, and for not much money. Two economic factors underlie this Garden of Electronic Eden that we’re living in. Economies of scale make the parts cheap: when a factory turns out the same MEMS accelerometer chip for hundreds of millions of cell phones, their setup and other fixed costs are spread across all of these chips, and a $40 million factory ends up only costing $0.50 per unit sold.

But the unsung hero of the present DIY paradise is how so many different parts are available, and from so many different suppliers, many of them on the other side of the globe. “The Internet” you say, as if that explains it. Well, that’s not wrong, but it’s deeper than that. The reason that we have so much to choose from is that the marginal cost of variety has fallen, and with that many niche products and firms have become profitable where before they weren’t.

So let’s take a few minutes to sing the praises of the most important, and sometimes overlooked, facet of the DIY economy over the last twenty years: the falling marginal cost of variety.

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Ultrasuede Bench Power Supply Got Style

From the look of it sitting on his bench, you’d never guess that [3nz01]’s power supply was actually a couple of el-cheapo modules from eBay, but now we all know the dirty truth.

Re-using or re-purposing an enclosure can be a great way to get a project done faster and get on to the next one. In [3nz01]’s case (tee-hee!), it was an old clock with a broken and annoying buzzer that needed to go. The clock was a nice piece of wood, but that Plexiglas front panel just wasn’t cutting it. That’s why it’s good to have a tailor for a father — a suitable piece of ultrasuede wrapped around the plexi makes the build look swank.

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Design For Hackers

Near the end of the lifecycle of mass-market commercial product development, an engineering team may come in and make a design for manufacturability (DFM) pass. The goal is to make the device easy, cheap, and reliable to build and actually improve reliability at the same time. We hackers don’t usually take this last step, because when you’re producing just a couple of any given device, it hardly makes sense. But when you release an open-source hardware design to the world, if a lot of people re-build your widget, it might be worth it to consider DFM, or at least a hardware hacker’s version of DFM.

If you want people to make their own versions of your project, make it easy and cheap for them to do so and don’t forget to also make it hackable. This isn’t the same as industrial DFM: rather than designing for 100,000s of boards to be put together by robot assembly machines, you are designing for an audience of penny-pinching hackers, each building your project only once. But thinking about how buildable your design is will still be worthwhile.

In this article, I’m going to touch on a couple of Design for Hackers (DFH) best practices. I really want to hear your experience and desires in the comments. What would you like to see in someone else’s open designs? What drives you nuts when replicating a project? What tricks do you know to make a project easily and cheaply buildable by the average hacker?

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