Tales From The Global Chip Shortage: Smoothieboard

July 17, 2021 by Stephen Ogier 27 Comments

The semiconductor shortage sparked by the pandemic is showing no signs of slowing down. Although auto manufacturers were some of the first affected, the shortage has now spread and is impacting all sorts of projects, including the Smoothieboard open-source CNC controllers.

[Chris Cecil] walks through the production woes they’ve had over the last few months. It began this spring with a batch of the V1.1 boards. The prices of some of their chips started jumping, and then they were informed that the microcontroller that serves as the brains of the Smoothieboard was only available for five times the old price. In the end, they placed a smaller order, and V1.1 Smoothieboards will likely be scarce until the microcontroller’s price returns to normal.

Getting V2 of the boards into production has been even more difficult. Just weeks before the final prototype, it was discovered that the LPC4330 microcontroller the V2 was built around was also sold out worldwide. With the shortage in mind, a hole was left in the layout of the final version of V2 so that they could finish the design around whatever microcontroller they were able to get. In the end, they were able to lock down a supply of STM32H745 controllers, which are actually substantially more capable than the original device.

If you’re interested in the origins of the chip shortage, this article from January is a good place to start. This isn’t the first time parts shortages have wreaked havoc on the world of electronics—does anyone remember the global resistor shortage of ’18?

A Perfect Clock For Any Hacker’s Ohm

July 15, 2021 by Adam Zeloof 29 Comments

The vast majority of us are satisfied with a standard, base ten display for representing time. Fewer of us like to be a bit old-fashioned and use a dial with a couple of hands that indicate the time, modulo twelve. And an even smaller minority, with a true love for the esoteric, are a fan of binary readouts. Well, there’s a new time-telling game in town, and as far as we’re concerned it’s one of the best ones yet: resistor color codes.

The Ohm Clock is, as you may have guessed, a giant model of a resistor that uses its color bands to represent time. Each of the four bands represents a digit in the standard HH:MM representation of time, and for anybody well-versed in resistor codes this is sure to be a breeze to read. The clock itself was designed by [John Bradnam]. It’s body is 3D printed, with RGB LEDs to brightly illuminate each segment. The whole thing is controlled by an old favorite – an ATtiny, supported by a Real Time Clock (RTC) chip for accurate timekeeping.

You can set the time in the traditional fashion using buttons, or — and here’s the brilliant part — you can use a resistor. Yup, that’s right. Connecting a 220 Ohm resistor across two terminals on the clock will set the time to 2:20. Genius.

When you come across an art as old as timekeeping, it’s easy to assume that everything’s already been done. We have sundials, hourglasses, analog clocks, digital watches, those cool clocks that use words instead of numbers, the list goes on. That’s why it’s so exciting to see a new (and fun!) idea like this one emerge.

NFC Who’s At The Door

July 13, 2021 by Michael Shaub 8 Comments

RevK_NFC_v1-Prototype-Photo — An early prototype that worked on the first try, except for one LED

[RevK] wanted to learn about NFC readers, and we agree that the best way to do so is to dive in and build one yourself.

There are readers available from multiple sources, but [RevK] found them either compact but with no prototyping space or plenty of prototyping space and a large footprint. High-speed UART (HSU) was selected over I2C for communication with an ESP32 as testing showed it was just as fast and more reliable over long distances at the cost of only one additional wire.

After a few versions, the resulting PN532 based NFC reader has just enough GPIO for a doorbell and tamper switch and three status LEDs, with board files and a 3D-printed case design included in the open source project on GitHub. When looking into the project, we appreciated learning about tamper switches that can include closed or open contact status when an NFC is read, most often used in the packaging of high-value and collectible products. If you have worked with this tamper feature of NFCs, let us know about it.

Thanks for the tip, [Simon]

From Printer To Vinyl Cutter

July 2, 2021 by Matthew Carlson 14 Comments

Some might look at a cheap inkjet printer and see a clunky device that costs more to replace the ink than to buy a new one. [Abhishek Verma] saw an old inkjet printer and instead saw a smooth gantry and feed mechanism, the perfect platform to build his own DIY vinyl cutter.

The printer was carefully disassembled. The feed mechanism was reworked to be driven by a stepper motor with some 3D printed adapter plates. A solenoid-based push/pull mechanism for the cutting blade was added with a 3D printed housing along with a relay module. An Arduino Uno takes in commands from a computer with the help of a CNC GRBL shield.

What we love about this build is the ingenuity and reuse of parts inside the old printer. For example, the old PCB was cut and connectors were re-used. From the outside, it’s hard to believe that HP didn’t manufacture this as a vinyl cutter.

If you don’t have a printer on hand, you can always use your CNC as a vinyl cutter. But if you don’t have a CNC, [Abhishek] shares all the STL files for his cutter as well as the schematic. Video after the break.

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Random Numbers From A Smoke Detector

June 26, 2021 by Jenny List 21 Comments

The quest for truly random numbers is something to which scientists and engineers have devoted a lot of time and effort. The trick is to find an unpredictable source of naturally occurring noise that can be sampled, so they have looked towards noisy gas discharge tubes or semiconductor junctions, and radioactive decay. Noisy electrical circuits have appeared in these pages before as random number generators, but we’d be forgiven for thinking that radioactive decay might involve something a little less run-of-the-mill. In fact we all probably have just such a device in our houses, in the form of the ionisation chamber that’s part of most household smoke detectors. [Lukas Koch] has built a project that shows us just how this can be done.

A smoke detector of this type uses a metal shell to house a tiny sample of radioactive americium that emits alpha particles into the space between two electrodes. These ionise the air in that space, and the detectable effect on the space between the two electrodes is increased when ionised gasses from smoke are present. However it can also quite happily detect the ionisation from individual alpha particles, which means that it’s perfect as a source of random noise. A sensitive current amplifier requires significant shielding to avoid the device merely becoming a source of mains hum, and to that end he’s achieved a working breadboard prototype.

This is still a work in progress and though it has as yet no schematic he promises us that it will arrive in due course. It’s a project that’s definitely worth watching, because despite getting more up-close and personal than most of us have with radioactive components, it’s one we’re genuinely interested to see come to fruition.

Of course, we’ve seen smoke detectors in more detail before here at Hackaday.

Where Are All The Cheap X86 Single Board PCs?

June 17, 2021 by Jenny List 154 Comments

If we were to think of a retrocomputer, the chances are we might have something from the classic 8-bit days or maybe a game console spring to mind. It’s almost a shock to see mundane desktop PCs of the DOS and Pentium era join them, but those machines now form an important way to play DOS and Windows 95 games which are unsuited to more modern operating systems. For those who wish to play the games on appropriate hardware without a grubby beige mini-tower and a huge CRT monitor, there’s even the option to buy one of these machines new: in the form of a much more svelte Pentium-based PC104 industrial PC.

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Z80 Family Reunion Discovered In Old PoS Card Swiper

June 14, 2021 by Chris Lott 19 Comments

[Ben Heck] found an old card-swipe point-of-sale box at the Goodwill store, took it home, and tore it down to see what was inside. He found a completely serviceable single board computer based on the Z80. In fact, there’s a whole family of four Z80 chips: the CPU itself, the DART chip (dual UART), the PIO chip (parallel input/output interface), and the CTC chip (counter/timer circuit). That’s not all — there’s a landline telephone modem, a real time clock, 32K of RAM and UV-EPROM. The second PCB of this assembly holds a hefty sixteen-key keypad and a sixteen-character vacuum fluorescent alphanumeric display. All this for the bargain price of $2.99.

Surely [Ben] will dig into the Z80 system in the future, but in this video he tries to make the display work. An OKI Semiconductor controller drives the VFD. After tracking down the data sheet, [Ben] wires it up to an Arduino and writes a quick program. Only a few YouTube minutes later, he conquers the display, drawing sample text anywhere he wants on the screen with any brightness he desires.

You never know what you may find lurking inside old equipment like this. You might find a proprietary ASIC with no documentation, or like [Ben] did here, you could find a fully functioning embedded computer. If [Ben] can whip up a RAM-based emulator to replace the 32K UV-EPROM, he’ll have a perfect evaluation board for Z80 projects.

Let us know in the comments if you have found any treasures like this. Also, how would you use this board if you had found it? Thanks to reader [Nikša Barlović] for sending in the tip.

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