Parts

761 Articles

The Chip Shortage Leads To The Strangest Things

August 13, 2022 by 19 Comments

The global chip shortage has not made the life of the electronic design engineer an easy one, as products have been designed around whatever parts are available rather than the first choices. This has manifested itself in some unexpected ways, including as [CNX software] investigates, products whose multiple-choice bill of materials has led to mistakes being made in manufacture.

On the face of it, designing a PCB with two sets of footprints to accommodate more than one part choice is a clever move. But as Radxa found out with their Rock 3A single board computer, this could lead to a production mishap as some boards left the production line with a mix-and-match BoM in their USB PD circuitry which left them unable to operate from voltages above 5 V. The board has footprints for both an Injoinic and a WCH part, and the faulty boards appear to have the support components fitted for the other chip to the one on the board.

We’d join [CNX] in congratulating Radxa for coming clean, and we like that one of the options to fix it is to be sent the chip to fit yourself. We’re left rather glad that it wasn’t us on whose watch such a mistake occurred, as from experience we know these things can happen all too easily.

Has the chip shortage led to any similar production mistakes in your life? Let us know in the comments.

Should’ve Used A 555 — Or 276 Of Them

August 10, 2022 by 33 Comments

When asked to whip up a simple egg timer, most of us could probably come up with a quick design based on the ubiquitous 555 timer. Add a couple of passives around the little eight-pin DIP, put an LED on it to show when time runs out, and maybe even add a pot for variable timing intervals if we’re feeling fancy. Heck, many of us could do it from memory.

So why exactly did [Jesse Farrell] manage to do essentially the same thing using a whopping 276 555s? Easy — because why not? Originally started as an entry in the latest iteration of our 555 Contest, [Jesse]’s goal was simple — build a functional timer with a digital display using nothing but 555s and the necessary passives. He ended up needing a few transistors and diodes to pull it off, but that’s a minor concession when you consider how many chips he replaced with 555s, including counters, decoders, multiplexers, and display drivers. All these chips were built up from basic logic gates, a latch, and a flip-flop, all made from one or more 555s, or variants like the 556 or 558.

As one can imagine, 276 chips take a lot of real estate, and it took eleven PCBs to complete the timer. A main board acts as the timer’s control panel as well as serving as a motherboard for ten other cards, each devoted to a different block of functions. It’s all neat and tidy, and very well-executed, which is in keeping with the excellent documentation [Jesse] produced. The whole thing is wonderfully, needlessly complex, and we couldn’t be more tickled to feature it.

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Turning A Pair Of Syringes Into A Tiny Water Pump

July 31, 2022 by 6 Comments

There is something inherently fascinating about tiny mechanical devices, especially when you’re used to seeing much larger versions. This is the case with [Penguin DIY]’s tiny centrifugal water pump built from 5 ml syringes.

The pump is powered by a small 8 mm diameter brushed DC motor, likely the same type that is used for small toy-grade quadcopters. The tiny impeller is a section of the syringe’s original plunger, with its cross-shaped body acting as the impeller blades. [Penguin DIY] first experimented with the original plunger seal to protect the motor from water, but it quickly melted from friction with the spinning shaft. Silicone sealant was used instead, and the motor shaft was covered with a layer of oil to prevent the sealant from sticking to it. Then the blob of sealant was flattened with a translucent plastic disc to allow clearance for the impeller.

A hole was drilled in the side of the syringe where the impeller sits, and a nozzle cut from the tip of another syringe was glued in place as the outlet. It’s notoriously difficult to get anything to stick to polypropylene syringes, but [Penguin DIY] says in the comments he was able to find an “organic superglue” that worked. With the motor and impeller inserted, the remaining space was also sealed with silicone.

This tiny pump packs a surprising amount of power, and was able to empty a 1.5 l bottle in about one minute with enough pressure to send the jet of water flying. There are still some issues that need to be addressed, though. With the motor completely sealed, it could burn itself quite quickly. A commenter also mentioned that it might suck water into the motor past the shaft after a hot run, as the air inside the motor cools and contracts. Even so, this little pump might be practical for applications that only require short runs, like watering potted plants. If you need more power you could always 3D print a larger pump.

Continue reading “Turning A Pair Of Syringes Into A Tiny Water Pump” →

Fix Old Caps, But Keep That “Can Capacitor” Look

July 30, 2022 by 21 Comments

Vintage electronics and capacitor replacements tend to go hand-in-hand. Why? Because electrolytic capacitors just don’t last, not the way most other components do, anyway.

The metal terminal ring and the central plate are kept for re-use, and the metal case re-crimped after the internals of the capacitor are replaced with a modern equivalent.

It’s one thing to swap old caps with modern replacements, but what about electronics where the components are not hidden away, and are an important part of the equipment’s look? [lens42] shares a method for replacing antique can-style capacitors in a way that leaves them looking completely original. All it takes is some careful application of technique.

The first thing to do is carefully file away the crimp of the metal can until one can release the ring and plate that hold the terminals. Once that is off, the internals can be pulled from the metal can for disposal. Since the insides of the old cap won’t be re-used, [lens42] recommends simply drilling a hole, screwing in a lag bolt to use as a handle, and pulling everything out. There’s now plenty of space inside the old can to hold modern replacements for the capacitor, and one can even re-use the original terminals.

That leaves the job of re-crimping the old can around the terminal ring to restore a factory-made appearance. To best do this, [lens42] created a tapered collar. Gently hammering the can forces the bottom into the taper, and the opening gradually crimps around the terminal ring. It’s also possible to carefully hammer the flange directly, but the finish won’t be as nice. This new crimp job may not look exactly the same as before, but once the cap is re-installed into the original equipment, it won’t be possible to tell it has been modified in any way.

If this sounds a bit intimidating, don’t worry. [lens42] provides plenty of pictures. And if this kind of thing is up your alley, you may want to check out the Caps Wiki, an effort to centralize and share details about tech repair, especially for vintage electronics.

A New Way To Produce PCBs With Your 3D Printer

July 26, 2022 by 50 Comments

With the low-cost PCB fabrication services available to hackers and makers these days, we’ll admit that making your own boards at home doesn’t hold quite the appeal that it did in the past. But even if getting your boards professionally made is cheaper and easier than it ever has been before, at-home production still can’t be beat when you absolutely must have a usable board before the end of the day.

If you find yourself in such a situation, this new method of DIY PCB production detailed by [Adalbert] might be just what you need. This unique approach uses a desktop fused deposition modeling (FDM) 3D printer throughout all of its phases, from creating a stencil based on the exported board design, to warming the UV soldermask to accelerate the curing process. It may not be an ideal choice for densely packed boards with fine-pitch components, but could definitely see it being useful for many prototypes.

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3D Printing A Check Valve In Metal

July 21, 2022 by 34 Comments

[SunShine] has been working on 3D printed pumps and similar parts with an aim towards building smaller and more compact hydraulic systems. His latest effort involves printing working hydraulic check valves that can be integrated seamlessly into his designs. 

Unlike many 3D printing enthusiasts, [SunShine] works with metal printers of the laser powder bed type. His expectations for his parts are thus very high, and he aimed to create check valves that could withstand high hydraulic pressures.

After much work, [SunShine] came up with two designs for 3D-printed check valves that would work. However, they both needed internal removal of support structures that couldn’t be achieved without cutting them open. He then figured out that he could use a special process using nitric acid to carefully eat away a very precise amount of metal inside the valves, which would remove the support material without destroying the whole valve itself.

While the valves couldn’t be tested beyond 400 bar due to the available equipment, they did work as intended. As a bonus, they actually sealed better as they were used more, as the sealing surfaces bedded in and deformed to match each other.

The video is then rounded out with a simple plastic check valve design you can print at home. It reminds us of other valves we’ve seen created with 3D printing before. Video after the break.

Continue reading “3D Printing A Check Valve In Metal” →

Ride DIY Or Die This Badge-Less Suzuki

July 3, 2022 by 12 Comments

A few years ago, [Charles] picked up a sweet Suzuki motorcycle that checked all the boxen: it was in good shape, bore a few useful upgrades and a box of spare parts, plus the price was right. Though he assumed that he had pored over every picture on the classified site before buying, it wasn’t until later that [Charles] realized that something was indeed missing from the bike — a piece of chrome that does little more than to cover the tee in the brake line and bear the Suzuki brand. Once he saw the problem, he couldn’t un-see it, you know? And at that point, he just had to have that little piece, even if he had to make it himself.

That wasn’t the original plan, of course, but bike parts are expensive to begin with and only get worse as size, condition, and rarity increase. [Charles]’ quest to find this piece was halfway successful; he found a reasonable-but-rusty facsimile of the right part, although the emblem portion was long gone. Then he remembered the wife’s vinyl cutter.

Now, let’s stop right there. If you know anything at all about these vinyl cutters, you know that they are basically glorified 2D plotters with a knife attached where a pen would be. Send it any 2D file and you’re good? No, no; of course not. These things are locked down by the manufacturers.

Fortunately, [Charles] found inkscape-silhouette, which makes light work of sending SVGs to the machine. After much back and forth and maybe a bit of coin-flipping, [Charles] settled on the classy, stylized ‘S’ version rather than the full-on Suzuki badge. We think it looks great, and we’ll never tell anyone.

While this isn’t quite the type of badge we’d normally talk about, it’s a great project nonetheless, and it’s always nice to hear about projects that open up otherwise closed-source hardware.