This ESP32 Pico Wristwatch Has Plenty Of Potential

February 12, 2022 by Dave Rowntree 12 Comments

First hand-built prototype. Nurse! isopropyl alcohol, stat!

Prolific hacker [Sulfuroid] is a medical doctor by day, and an electronics hobbyist by night, and quite how he finds the time, we have no idea.

The project we want to highlight is an ESP32 based LED smart watch, which we’ll sure you’ll agree, looks pretty nicely developed so far, and [Sulfuroid] has bigger plans, as you may find, when you dig into the GitHub repo. This analog-style design uses four groups of 0603-sized LEDs, arranged circularly to indicate the passage of time, or anything else you fancy. Since there are four control buttons, a pancake vibration motor, as well as Wi-Fi and Bluetooth, the possibilities are endless.

In order to stand a hope of driving those 192 LEDs from a single ESP32-Pico-D4, it was necessary to use a multiplexed LED driver, courtesy of the Lumissil IS31FL3733 device, which can handle arrays up to 12 x 16 devices. This chip is one to remember, since it has some really nice features, such as global current control to reduce CPU overhead, automatic breathing loops for those fancy fade effects, and even includes a handy open/short detection function, so it can report back assembly problems, assisting in reworking your dodgy soldering!

Power and interfacing are taken care of via USB-C, with a TP4054 single Li-Ion cell charger chip handling the battery. This is a Taiwanese clone of the popular LTC4054, but that chip may be a bit hard to get at the moment. There is the common-as-muck CP2104 USB chip dealing with the emulated serial port side of things, since for some reason, the ESP32 still does not support USB. The Pico-D4 does have RTC support, but [Sulfuroid] decided to use a DS3231M RTC chip instead. We noticed the touch functionality wasn’t broken out – that could be added easily in the next revision!

We’ve covered watches a lot, because who doesn’t want custom geek-wear! Here’s a slick one, a fun one with the brains on display, and finally one using charlieplexing to get the component count down.

Genius Or Cursed, This USB-C Connector Is Flexible

January 1, 2022 by Jenny List 18 Comments

USB connectors have lent themselves to creative interpretations of their mechanical specifications ever since the first experimenter made a PCB fit into a USB-A socket. The USB-C standard with its smaller connector has so far mostly escaped this trend, though this might be about to change thanks to the work of [Sam Ettinger]. His own description of his USB-C connector using a flexible PCB and a BGA-packaged ATTiny84A microcontroller is “cursed”, but we can’t decide whether or not it should also be called “genius”.

Key to this inspired piece of connector fabrication is the realization that the thickness of BGA and flex PCB together comes to the required 0.7 mm. The BGA provides the necessary stiffness, and though it’s a one-sided connector it fits the space perfectly. There are several demo boards as proofs-of-concept, and the whole lot can be found in a GitHub repository.

We can see this technique finding a use in all kinds of diminutive USB-C projects, however cursed or genius it may be. We like to see projects that push the edges of what can be done with the medium, with a nod to a previous cursed USB-C device.

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Why Wait For Apple? Upgrade Your IPhone With USB-C Today!

October 15, 2021 by Jenny List 22 Comments

Apple iPhones ship with the company’s Lightning cable, a capable and robust connector, but one that’s not cheap and is only useful for the company’s products. When the competition had only micro-USB it might have made sense, but now that basically all new non-fruity phones ship with USB-C, that’s probably the right way to go.

[Ken Pilonell] has addressed this by modifying his iPhone to sport a USB connector. The blog post and the first video below the break show us the proof of concept, but an update in the works and a teaser video show that he made it.

We’re a bit hazy on the individual iPhone model involves, but the essence of the work involves taking the internals of a Lightning-to-USB-C cable and hooking it up to the phone’s internal Lightning port. The proof-of-concept does it by putting the Apple flexible PCB outside the phone and plugging the cable part in directly, but it seems his final work involves a custom flexible board on which the reverse-engineered USB-C converter parts are mounted along with the USB-C socket itself. We see a glimpse of machining the slot in the phone’s case to USB-C dimensions, and we can’t wait for the full second installment.

It’s purely coincidental, but this comes against a backdrop of the European Union preparing to mandate USB-C on all applicable devices.

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Adding Wireless Charging To The Switch Lite

October 13, 2021 by Tom Nardi 3 Comments

The Nintendo Switch is a monstrously popular machine, and it’s had no difficulty raking in the bucks for the Japanese gaming giant, but there’s no denying that it’s technologically a bit behind the curve. Until the long-rumored “Pro” version of the Switch materializes, industrious gamers like [Robotanv] will simply have to make up for Nintendo’s Luddite ways by hacking in their own upgraded hardware.

In this case, [Robotanv] wanted to add Qi wireless charging to his Switch Lite. He figured that if all of his other mobile devices supported the convenient charging standard, why not his portable gaming system? Luckily, the system already supports the increasingly ubiquitous USB-C, so finding an aftermarket Qi receiver that would connect to it was no problem. He just needed to install it into the handheld’s case.

After liberating the Qi receiver from its protective pouch enclosure to get it a bit thinner, [Robotanv] taped it to the inside of the system’s case and ran thin wires to the rear of the USB-C port. As luck would have it, Nintendo was kind enough to put some test pads for the power pins right behind the port, which made for an ideal spot to connect the charger.

At first he only connected the positive and negative lines from the charger, but quickly realized he also had to connect the CC pin to get the juice flowing. After that, it was just a matter of buttoning the system back up. All told, it looks like a pretty simple modification for anyone who’s not bashful about taking a soldering iron to their $199 console.

We’ve seen these Qi receivers retrofitted into devices before, and it remains an excellent way to add the feature not only to commercial products, but to your own projects.

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Showdown Time For Non-Standard Chargers In Europe

October 12, 2021 by Jenny List 115 Comments

It seems that few features of a consumer electronic product will generate as much rancour as a mobile phone charger socket. For those of us with Android phones, the world has slowly been moving over the last few years from micro-USB to USB-C, while iPhone users regard their Lightning connector as the ultimate in connectivity. Get a set of different phone owners together and this can become a full-on feud, as micro-USB owners complain that nobody has a handy charging cable any more, USB-C owners become smug bores, and Apple owners do what they’ve always done and pretend that Steve Jobs invented USB. Throwing a flaming torch into this incendiary mix is the European Union, which is proposing to mandate the use of USB-C on all phones sold in its 27 member nations with the aim of reducing considerably the quantity of e-waste generated.

Minor annoyances over having to carry an extra micro-USB cable for an oddball device aside, we can’t find any reason not to applaud this move, because USB-C is a connector born of several decades of USB evolution and brings with it not only the reversible plug but also the enhanced power delivery standards that enable fast charging no matter whose USB-PD charger you are using. Mandating USB-C will put an end to needlessly overpriced proprietary cables, and bring eventual unity to a fractured world. Continue reading “Showdown Time For Non-Standard Chargers In Europe” →

Powering Up With USB: Untangling The USB Power Delivery Standards

September 16, 2021 by Maya Posch 37 Comments

Powering external devices directly from a PC’s I/O ports has been a thing long before USB was even a twinkle in an engineer’s eye. Some of us may remember the all too common PS/2 pass-through leads that’d tap into the 275 mA that is available via these ports. When USB was first released, it initially provided a maximum of 500 mA which USB 3.0 increased to 900 mA.

For the longest time, this provided power was meant only to provide a way for peripherals like keyboards, mice and similar trivial devices to be powered rather than require each of these to come with its own power adapter. As the number of computer-connected gadgets increased USB would become the primary way to not only power small devices directly, but to also charge battery-powered devices and ultimately deliver power more generally.

Which brings us to the USB Power Delivery (USB-PD) protocol. Confusingly, USB-PD encompasses a number of different standards, ranging from fixed voltage charging to Programmable Power Supply and Adjustable Voltage Supply. What are the exact differences between these modes, and how does one go about using them? Continue reading “Powering Up With USB: Untangling The USB Power Delivery Standards” →

Building A Solar Powered Game Boy Pocket

August 8, 2021 by Matthew Carlson 5 Comments

Light has always been a key part of the classic Game Boy experience. Some of us have fond memories of riding along in the back seat of a car at night, pausing and unpausing the game as the street lights overhead briefly give enough light to see the unlit display. The availability of third party IPS displays for these classic handhelds has largely eradicated this problem today, but as you might expect, the increased power requirements of the more modern screen reduces the system’s runtime.

As part of their examination into energy production, the [Houston Museum of Natural Science] set out to see if they could improve things by adding a solar panel to the back of a Game Boy Pocket that had already been modified with an IPS display. The Pocket version of the Game Boy was selected as it has a nice flat back that made it easy to attach a solar panel, and in fact the panel sourced for this mod is so well dimensioned, it almost looks like the device came that way.

In the video below, you can see the modification starts by cutting away a large section of the Game Boy’s rear panel to fit the 1000 mAh LiPo battery. The solar panel is then affixed over the back with super glue. A diode is soldered onto the solar cell, and then wired into a charge controller that came with USB-C input. The placement of the charge controller ended up being trickier than expected, but with a little hot glue, it works just fine. Overall this is a simple mod but a brilliant idea.

This isn’t the first solar-powered handheld game system we’ve seen, but it’s nice to see the idea revisited and expanded on, particularly regarding ergonomics. In addition, we love the incredible detail of narration that’s given as this hack slowly takes shape. Video after the break.

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