Bench Supplies Get Smaller Thanks To USB-C

October 19, 2020 by Bryan Cockfield 17 Comments

Bench power supplies are an indispensable tool when prototyping electronics. Being able to set custom voltages and having some sort of current limiting feature are key to making sure that the smoke stays inside all of the parts. Buying a modern bench supply might be a little too expensive though, and converting an ATX power supply can be janky and unreliable. Thanks to the miracle of USB-C, though, you can build your own fully-featured benchtop power supply like [Brian] did without taking up hardly any space, and for only around $12.

USB-C can be used to deliver up to 100W but is limited to a few set voltage levels. For voltages that USB-C doesn’t support, [Brian] turns to an inexpensive ZK-4KX buck-boost DC-DC converter that allows for millivolt-level precision for his supply’s output. Another key aspect of using USB-C is making sure that your power supply can correctly negotiate for the amount of power that it needs. There’s an electronic handshake that goes on over the USB connection, and without it there’s not a useful amount of power that can be delivered. This build includes a small chip for performing this negotiation as well.

With all the electronics taken care of, [Brian] houses all of this in a 3D-printed enclosure complete with a set of banana plugs. While it may not be able to provide the wattage of a modern production unit, for most smaller use cases this would work perfectly. If you already have an ATX supply around, though, you can modify [Brian]’s build using that as the supply and case too.

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Building A USB-C Charger For Canon NB-4L Batteries

September 23, 2020 by Tom Nardi 17 Comments

One of the most appealing aspects of USB-C is that it promises to be a unified power delivery system. You’ll no longer need to have a separate power cords for for your phone, camera, and laptop; physically they’ll all use USB-C connectors, and the circuitry in the charger will know how much juice to send down the line for each gadget. But in reality, we’ve all got at least a few pieces of older equipment that we’re not about to toss in the trash just because it doesn’t support the latest USB spec.

Case in point, the old Canon camera that [Purkkaviritys] modified to take infrared pictures. Instead of abandoning it, he decided to make a custom USB-C charger for its NB-4L batteries. Since they’re just single cell 3.7 V lithium-ions, all he had to do was wire them up to the ubiquitous TP4056 charger module and design a 3D printed case to hold everything together.

He did go the extra mile and replace the SMD charging indicator LEDs on the PCB with 5 mm LEDs embedded into the 3D printed enclosure, though you could certainly skip this step if you were in a hurry. We imagine if you print the enclosure in a light enough color, you should be able to see the original LEDs glowing through the plastic.

This project is yet another example of how incredibly useful the TP4056 module really is. If there’s even a chance you might want to build a rechargeable gadget in the near future, you should have a few of these cheap boards ready to go in the parts bin.

Fewer Millimeters Make A Useful ESP32 Devboard

July 31, 2020 by Kerry Scharfglass 32 Comments

Sometimes the most useful hacks aren’t the flashiest, they’re the ones that improve an already great tool and make something better. Through hole components are still the fastest and perhaps most satisfying way to prototype a new electronics project so it’s extra frustrating when the happy hacker discovers their new devboard is too wide to fit in a standard breadboard. [Tobias] had the same thought and redesigned the standard ESP32 “NodeMCU” style devboard to be almost exactly the same, but narrower.

Not to trivialize, but that’s pretty much it. And we love it! The new design retains the great support of the original devboard but adds a few nice tweaks. Obviously there’s the small size change that allows it to fit on a standard 5×5 breadboard leaving sockets available on either side for interfacing. Even in this smaller size [Tobias] managed to retain the boot mode and reset buttons though the overall pinout has changed slightly. And for easier connections ye olde micro USB socket has been swapped for sleek modern USB-C. You have cables for that common standard now, right?

How do you get one? As far as we know [Tobias] isn’t selling these but the design is completely open source and the design, fab, and BOM files are all in the github repository. [Tobias] even went so far as to include the extremely handy interactive BOM to speed up hand assembly. The real trick here is that the board is designed to facilitate the extremely inexpensive turnkey assembly now available from our favorite fab houses, with an example cost of $8/piece for a run of five. The repo includes a properly formatted BOM and fab files to make ordering them a snap. See the bottom of the README for details about what to order.

USB-C Where It Was Never Intended To Be

July 24, 2020 by Jenny List 25 Comments

The USB-C revolution is well under way, as first your new phone, then your single-board computer, and now your laptop are likely so sport the familiar reversible round-cornered connector. We’re still in the crossover period of requiring to keep micro USB, proprietary laptop, and USB-C power supplies at hand, but the promise of a USB-C-only world is tantalisingly close. For [Purkkaviritys] that’s a little bit closer now, as he’s modified his Thinkpad T440s to take a USB charger instead of its proprietary Lenovo square-plug part. (Video, embedded below.)

At its heart is a USB-PD emulator module that does all the hard work of negotiation with the power supply, giving the laptop the DC voltage it needs. It’s not quite that simple though, because a resistor is required to reassure the laptop that it’s got a genuine power supply. The module is encased in a carefully-designed surround that neatly takes the space vacated by the original connector, and since this laptop has its internal power connector on a short cable it is made very straightforward to fit into the case. If you didn’t know it was a home-made upgrade, you could be forgiven for thinking that this laptop left the factory with a USB-C power socket.

The USB-C module used here is a versatile part. We’ve previously seen it in a soldering iron conversion.

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Hacking A ThinkPad USB-C Adapter

June 28, 2020 by Lewin Day 29 Comments

USB-C has brought the world much more powerful charging options in a slimline connector. With laptop chargers and portable battery packs using the standard, many with older hardware are converting their devices over to work with USB-C. [victorc] was trying to do just that, purchasing an adapter cable to charge a ThinkPad. Things didn’t quite work out of the box, so some hacking was required.

The problem was the power rating of the adapter cable, versus the battery pack [victorc] was trying to use. In order to allow the fastest charging rates, the adapter cable features a resistor value which tells the attached Lenovo laptop it can draw up to 90 W. The battery pack in question could only deliver 45 W, so it would quickly shut down when the laptop tried to draw above this limit.

To rectify this, [victorc] looked up the standard, finding the correct resistor value to set the limit lower. Then, hacking open the cable, the original resistor on the Lenovo connector was removed, and replaced with the correct value. With this done, the cable works perfectly, and [victorc] is able to charge their laptop on the go.

For all the benefits USB-C has brought, there’s been plenty of consternation, too. Whether this clears up, only time will tell!

USB-C Is Taking Over… When, Exactly?

June 23, 2020 by Lewin Day 179 Comments

USB is one of the most beloved computer interfaces of all time. Developed in the mid-1990s, it undertook a slow but steady march to the top. Offering an interface with good speeds and a compact connector, it became the standard for hooking up interface devices, storage, and even became the de-facto way to talk old-school serial, too.

In late 2014, the USB Implementers Forum finalised the standard for the USB-C plug. Its first major application was on smartphones like the Nexus 5X, and it has come to dominate the smartphone market, at least if you leave aside the iPhone. However, it’s yet to truly send USB-A packing, especially on the desktop. What gives? Continue reading “USB-C Is Taking Over… When, Exactly?” →

Solving Buyer’s Remorse With A Rotary Tool And Soldering Iron

June 9, 2020 by Sven Gregori 19 Comments

At this point, it’s pretty clear that USB-C has become the new standard connector for an increasing amount of applications, but predominantly charging. Even Apple is on board this time, and thanks to backwards compatibility, you don’t have to abandon devices using the older standards you may prefer for their simplicity or superior lint-resilience either. For [Mat] on the other hand, it’s USB-C all the way nowadays. Yet back in the day when he bought his laptop, he had the price tag convince him otherwise, and has come to regret it, as all the convenience of a slim design is cancelled out by dragging a bulky charger for the laptop’s proprietary charging port along.

Well, as the saying goes for situations like this: love it, leave it, or get out the tools and rework that sucker. Lucky enough, the original charger provides 20 V, which matches nicely the USB power delivery (PD) specification, and after opening up the laptop, [Mat] was happy to see that the interior provided enough room to fit the USB-C module he was planning to use. Even better, the charging port itself was a standalone component attached to a cable, so no modifications to the mainboard were necessary. Once the USB-C module was soldered to that same cable, the only thing left to do was carving a bigger hole on the laptop case, and saying good bye to the obsoleted charger.

The downside is of course the lack of actual USB functionality with that shiny new charging port, but that was never the goal here anyway. With more and more USB-C devices popping up, it’s also no surprise that we’ve seen modifications like this before, and not only with laptops. In case you’re thinking of upgrading one of your own devices to USB-C, and do wish for actual USB functionality, don’t worry, we got you covered as well.

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