Parts

717 Articles

Mobile Power From Cordless Tool Batteries

June 12, 2020 by 26 Comments

For years, [Michael Davis] has been using a large lead-acid battery to power the electronic components of his custom Dobsonian telescope; but that doesn’t mean he particularly enjoyed it. The battery was heavy, and you always had to be mindful of the wires connecting it to the scope. Looking to improve on the situation somewhat, he decided to build an adapter for Ryobi cordless tool batteries.

[Michael] had already seen similar 3D printed adapters, but decided to make his the traditional way. Well, sort of. He used a CNC router to cut out the distinctive shape required to accept the 18 V lithium-ion battery pack, but the rest was assembled from hardware store parts.

Bent mending plates with nuts and bolts were used to create adjustable contacts, and a spring added to the top ensures that there’s always a bit of tension in the system so it makes a good electrical contact. This setup makes for a very robust connector, and as [Michael] points out, the bolts make a convenient place to attach your wires.

With the logistics of physically connecting to the Ryobi batteries sorted out, the next step was turning that into useful power for the telescope. A stable 12 V is produced by way of a compact DC-DC converter, and a toggle switch and fuse connect it to a pair of automotive-style power sockets. Everything is held inside of a wooden box that’s far smaller and lighter than the lead-acid monster it replaced, meaning it can get mounted directly to the telescope rather than laying on the ground.

If you want to build a similar adapter, the 3D printing route will potentially save you some time and effort. But we have to admit that the heavy-duty connection [Michael] has rigged up here looks quite stout. If you’ve got an application where the battery could be knocked around or vibrated lose, this may be the way to go.

The Descendants Of Ancient Computers

May 31, 2020 by 13 Comments

Building computers from discrete components is a fairly common hobby project, but it used to be the only way to build a computer until integrated circuits came on the scene. If you’re living in the modern times, however, you can get a computer like this running easily enough, but if you want to dive deep into high performance you’ll need to understand how those components work on a fundamental level.

[Tim] and [Yann] have been working on replicating circuitry found in the CDC6600, the first Cray supercomputer built in the 1960s. Part of what made this computer remarkable was its insane (for the time) clock speed of 10 MHz. This was achieved by using bipolar junction transistors (BJTs) that were capable of switching much more quickly than typical transistors, and by making sure that the support circuitry of resistors and capacitors were tuned to get everything working as efficiently as possible.

The duo found that not only are the BJTs used in the original Cray supercomputer long out of production, but the successors to those transistors are also out of production. Luckily they were able to find one that meets their needs, but it doesn’t seem like there is much demand for a BJT with these characteristics anymore.

[Tim] also posted an interesting discussion about some other methods of speeding up circuitry like this, namely by using reach-through capacitors and Baker clamps. It’s worth a read in its own right, but if you want to see some highlights be sure to check out this 16-bit computer built from individual transistors.

Psst – Wanna Buy A Control Panel From A Nuclear Power Station?

May 28, 2020 by 73 Comments

Doing the rounds today is an interesting lot in an otherwise unexciting industrial dispersal auction in Lincolnshire, UK. On sale is an “Ex nuclear plant reactor control/monitoring system“, at the time of writing attracting the low low bid of £220 ($270), but we guess it will rise. Everyone who has watched Chernobyl (or maybe The Simpsons) is now gazing awestruck at a crescent of metal consoles covered in screens, buttons, and joysticks just waiting for a staff of white-coated technicians to pore over them.

Chernobyl Unit 3 control room (still active). [Source: IAEA Imagebank on Flickr CC-SA 2.0]
It’s a very cool lot indeed, but it raises more questions than it answers. The auction house has very little information indeed, so we’re left guessing, where did it come from? From this image showing the unit 3 control room at Chernobyl it’s obvious didn’t come from there (/s). Since it is for sale in the UK, and the country has decommissioned the majority of its first-generation reactors by now, so there is no shortage of candidates. But that intriguing possibility raises another question. Is it even a reactor control panel in the first place?

British civilian nuclear plants have tight security but they are hardly a secret, so plenty of photos are online showing their interiors. And in studying those we hit a problem, this panel doesn’t resemble any of the control panel images we can find. The first generation of Magnox (Magnetic Oxide Magnesium Non Oxidising) plants had panels covered in analogue dials and chart recorders so it’s unlikely to be one of those. The second-generation AGR (Advanced Gas-cooled Reactor) stations had similarly complex panels, and it’s evidently not one of them.

Looking closely at the photos it becomes apparent that there are a lot of camera controls and monitors, and even what looks like a uMatic video recorder. It’s definitely nuclear-related and the 1980s look of it suggests maybe it could have come from an Advanced Gas-Cooled Reactor (AGR) station, but could it be a little closer to Sector 7G than the centre of the action? Is it a video monitoring console used to keep a physical eye on its operation?

Be careful if you bid, you could end up with a rather cool but absurdly large 1980s CCTV system. Can any of our readers shed any light on the matter?

Thanks [Gregg “Cabe” Bond] for the tip.

Milling A Custom 6-Pin DIN Connector

May 22, 2020 by 18 Comments

When [Charles Ouweland] found himself in need of a DIN connector that had a somewhat unusual pin arrangement, he figured he could fashion his own in less time than it would take to have a replacement shipped to him. In the end it sounds as though it took a lot longer than expected, but given the worldwide situation, we don’t doubt this bespoke connector was still put to work before its eBay counterpart would have arrived.

More importantly, the connector [Charles] produced looks fantastic. If we weren’t told otherwise, we’d have assumed the finished product was commercially produced. Although to be fair, he did have a little help there. The housing and pins themselves were pulled from a sacrificial connector; his primary contribution was the insulating block that holds the pins in their proper position.

So how did he make it? He had considered using a piece of scrap material and just putting the holes in it with a drill press, but he was worried getting the aliment right. Instead, he decided to call his cheap CNC router into service. By routing his design out of copper clad PCB, he was even able to tie the appropriate pins together right in the connector.

Admittedly, we don’t see a lot of hardware that still uses DIN connectors these days. But this tip is certainly worth filing away just in case. You never know when you might find an old piece of hardware that just needs a little TLC to get up and running again. Who knows, you might even find a dumpster full of them.

New Teensy 4.1 Arrives With 100 Mbps Ethernet, High-Speed USB, 8 MB Flash

May 11, 2020 by 83 Comments

It was only last August that PJRC released Teensy 4.0. At that time, the 4.0 became the fastest microcontroller development board on the planet, a title it still holds as of this writing — or, well, not exactly. Today the Teensy 4.1 has been released, and using the same 600 MHz ARM Cortex M7 under the hood, is now also the fastest microcontroller board. What the 4.1 brings to the table is more peripherals, memory, and GPIOs. While Teensy 4.0 used the same small form factor as the 3.2, Teensy 4.1 uses the larger board size of the 3.5/3.6 to expose the extra goodies.

The now slightly older Teensy 4.0 — released on August 7th of last year — is priced at $19.95, with the new 4.1 version offered at $26.85. It seems that the 4.1 isn’t intended as a replacement for the 4.0, as they serve different segments of the market. If you’re looking for an ultra-fast affordable microcontroller board that lives up to its Teensy name, the 4.0 fits the bill. On the other hand, if you need the additional peripherals broken out and can afford the space of the larger board, the not-as-teensy-sized 4.1 is for you. How big is it? The sample board I measured was 61 x 18 mm (2.4 x 0. 7″), not counting the small protrusion of the micro-usb jack on one end.

Let’s have a look at all the fun stuff PJRC was able to pack into this space. Continue reading “New Teensy 4.1 Arrives With 100 Mbps Ethernet, High-Speed USB, 8 MB Flash” →

Arm Gives Gift To Startups: Zero Cost

May 4, 2020 by 24 Comments

Who hasn’t dreamed of pulling together some gadget in their garage and turning it into a big business? Of course, most gadgets today have a CPU in them, and Arm CPUs power just about any kind of embedded device you can think of. If you just want to use a chip, that’s easy. You buy them from a licensee and you use their tools for development. But if you want to integrate ARM’s devices into your own chips, that’s a different story. You have to pay fees, buy tools, and pay licenses on each chip you produce. Until now. Arm’s flexible access for startups program will let you apply to get all of that free.

To qualify, you have to be an “early stage silicon startup with limited funding.” Normally, flexible access costs about $75,000 to $200,000 a year and that doesn’t cover your license fees and royalties. The plan offered to qualifying startups is the $75,000 package, but that still includes access to nearly all Arm products, technical support, a few introductory training credits, and development tools. After your first tape-out, though, it looks as though you’ll have to pony up.

Continue reading “Arm Gives Gift To Startups: Zero Cost” →

Take This Cylindrical Coupler Design For A Spin

May 4, 2020 by 19 Comments

We’re not exactly sure what kind of shenanigans [Conrad Brindle] gets himself into, but apparently it often requires cylindrical couplings to attach 3D printed parts to each other. He found himself designing and redesigning this type of connector so often that he decided to just make a parametric version of it that could be scaled to whatever dimensions are necessary for that particular application.

In the video after the break, [Concrad] explains the concept behind the coupler and how he designed it. Put simply, the tabs inside of the coupler are designed to grab onto each other once the coupler is spun. When he demonstrates the action, you can see that both sides of the coupler are pulled together tightly with a satisfying little snap, but then can be easily removed just by rotating them back in the opposite direction.

The nature of desktop 3D printing means that the female side of the connection requires support when printing, and depending on your printer, that might mean a relatively rough mating surface. [Conrad] notes that you’ll need to experiment a bit to find how small your particular machine can print out the design before things get too gummed up.

We can see how this would be useful for some applications, but if you need a printed joint that can handle a decent amount of torque before giving up the ghost, you might want to look into (mis)using one half of a spider coupling.

Continue reading “Take This Cylindrical Coupler Design For A Spin” →