[Glen]’s project sounds perfectly straightforward: have a big industrial-style push button act as a one-key USB keyboard. He could have hacked something together in any number of ways, but instead he decided to create a truly elegant solution. His custom PCB mates to the factory parts perfectly, and the USB cable between the button and the computer even fits through the button enclosure’s lead hole.
It turns out that industrial push buttons have standardized components which can be assembled in an almost LEGO-like manner, with components mixed and matched to provide different switch actions, light indicators, and things of that nature. [Glen] decided to leverage this feature to make his custom PCB (the same design used in his one-key keyboard project) fit just like a factory component. With a 3D printed adapter, the PCB locks in just like any other component, and even lines up with the lead hole in the button’s enclosure for easy connecting of the USB cable.
What does [Glen] use the big button for? Currently he has two applications: one provides a simple, one-button screen lock on a Linux box running a virtual machine at his place of work. It first disengages the keyboard capture of the virtual machine, then engages the screen lock on the host. The other inserts a poop emoji into Microsoft documents. Code and PCB design files for [Glen]’s small keyboards are available on GitHub.
What if there were something like a KVM switch for your micro programmer, logic analyzer, and other various tools? There was a time when KVM switches (keyboard, video, and mouse, by the way) were metal enclosures surrounding an absurdly complicated rotary switch. This fact has a few applications if you ever want to switch a whole lot of stuff; if you ever need a bazillion-pole, two-way rotary switch, don’t spend your money at Mouser or Digikey, just look at eBay for some really old KVM or parallel port switches. Modern times require modern solutions, so here’s a 16-channel, bi-directional switched bus multiplexer. It connects wires to other wires with USB control, and if you need something like this, you really need something like this.
The SensorDots Port MuxR is a crowdfunding project for a project that began as a programming jig for another project. The MappyDot is a micro LIDAR unit that’s about the size of a postage stamp and has a microcontroller. Obviously, programming those microcontrollers was a pain (and don’t get me started on buying pre-programmed microcontrollers from the manufacturer), but there was a solution: a custom programming rig with dozens of pogo pins that automated the programming of an entire panel of boards. It was a useful tool, and now it’s a good idea for a Kickstarter project.
The Port MuxR takes a set of eight pins, and sends that out to one of eight ports. Alternatively, it can take a set of four pins, and send that to sixteen ports. All of this is controlled via USB, and it works with 0-5V signaling. If you know what this means, you probably have a reason to be interested in it.
Is it a sexy project? No, not at all. It’s an 8-pole, 8-throw rotary switch, controllable over USB. It is interesting, and it’s something a lot of us are going to need eventually.
The keyboard and mouse are great, we’re big fans. But for some tasks, such as seeking around in audio and video files, a rotary encoder is a more intuitive way to get the job done. [VincentMakes] liked the idea of having a knob he could turn to adjust his system volume or move forward and backwards through a stream in VLC, but he also wanted to be able to repeatedly enter keyboard commands with it; something commercial offerings apparently weren’t able to do.
So he decided to build his own USB knob that not only looks fantastic, but offers the features he couldn’t find anywhere else. It’s another project which proves that DIY projects don’t have to look DIY. In fact, they can often give their commercial counterparts a run for their money. But this “Infinity USB Knob” isn’t just a pretty face, it allows the user to do some very interesting things such as quickly undo and redo changes to see how they compare.
As you might imagine, the electronics for this project aren’t terribly complex. The main components are the Adafruit Trinket M0 microcontroller and the EC11 rotary encoder itself. To provide nice visual feedback he added in a NeoPixel ring, but that’s not strictly necessary if you’re trying to rig this up yourself. Though we have to say the lighting effects are a big part of what makes this build look so good.
Though certainly not the only part. The aluminum enclosure, combined with the home theater style knob on the encoder, really give the finished product a professional look. We especially like his method of drilling out the top of the case and filling in the holes with epoxy to create easy and durable LED diffusers. Something to keep in mind for your next control panel build, perhaps.
[VincentMakes] has done an excellent job of documenting the hardware and software sides of this build on Hackaday.io, and gives the reader enough information that replicating this project should be pretty straightforward for anyone who’s interested. While we’ve seen several rotary encoder peripherals for the computer in the past, we have to admit this is one of the most compelling yet from a visual and usability standpoint. If this build doesn’t make you consider adding a USB knob to your arsenal, nothing will.
Continue reading “A Classy USB Knob For The Discerning Computerist”
When we get a new device these days, somewhere in the package is likely to be a wall-wart USB power supply. We look for a place to plug in the little switch-mode dongle, rearrange a few plugs in the mains power strip, and curse its designers for the overly cozy outlet spacing. And all the while that USB-A plug on the power supply cable taunts us with its neat, compact form factor. If only there were a USB power strip.
Unwilling to suffer such indignity any longer, [Scott M. Baker] took matters into his own hands and designed this USB power distribution system. We were surprised to hear that he was unable to find a commercial USB power strip, but even if he had, it likely wouldn’t have had the bells and whistles that he added to his. The circuit went through a couple of revs, but each was focused on protection of the connected USB devices. He included both overcurrent protection, in the form of an electronic fuse built around a TPS2421 hot-swap controller, and overvoltage protection using a crowbar circuit with the usual zener-SCR arrangement. There’s also a transient voltage suppression diode to keep any inductive spikes at bay. Interestingly, each USB outlet has all these protections – it’s not just one protected bus feeding a bunch of USB outlets in parallel, but individual modules with all the circuitry. The modules are gangable and live inside a laser-cut acrylic case. The video below shows the design and build process in some detail.
We have to say that we always learn a lot about circuit design from [Scott]’s projects. You may recall his custom Atari 2600 controller or his dual-port memory retro game console, both interesting and instructive builds in their own right.
Continue reading “Well-Protected USB Power Strip Makes It Easy to Plug In”
DC power bricks were never a particularly nice way to run home electronics. Heavy and unwieldy, they had a tendency to fall out and block adjacent outlets from use. In recent years, more and more gadgets are shipping with USB ports for power input. However, power over USB has always been fraught with different companies using all manner of different methods to communicate safe current limits between chargers and hardware.
These days, we’re lucky enough to have the official USB Power Delivery standard in place. Even laptop chargers are using USB now, and [FPVtv DRONES] decided to see if it was possible to use such a device as a high current power supply to charge batteries.
The test starts with a MI brand USB C laptop charger. A USB power meter is plugged inline to determine voltage and current output of the charger, while a small microcontroller device is used to speak with the laptop charger and set it to high voltage, high current delivery mode. A lithium battery charger is then plugged in, and the setup is tested by charging two large 4-cell LiPos at over 1.4 amps concurrently.
The setup demonstrates that, with the right off-the-shelf modules, it’s possible to use your laptop charger to run high-current devices, as long as you can spoof it into switching into the right mode. This is the natural evolution of USB power technology – a road which started long ago with projects like the MintyBoost, way back when. Video after the break.
Continue reading “Charging LiPos with USB Power Delivery”
Just for the challenge, just for fun, just for bragging rights, and just to do a little showing off – all perfectly valid reasons to take on a project. It seems like one or more of those are behind this tiny ESP32 board that’s barely larger than the coin cell that powers it.
From the video below, [Mike Rankin] has been working down the scale in terms of powering and sizing his ESP32 builds. He recently completed a project with an ESP32 Pico D4 and an OLED display that fits exactly on an AA battery holder, which he populated with a rechargeable 14550. Not satisfied with that form factor, he designed another board, this time barely larger than the LIR2450 rechargeable coin cell in its battery holder. In addition to the Pico D4, the board sports a USB charging and programming socket, a low drop-out (LDO) voltage regulator, an accelerometer, a tiny RGB LED, and a 96×16 OLED display. Rather than claim real estate for switches, [Mike] chose to add a pair of pads to the back of the board and use them as capacitive touch sensors. We found that bit very clever.
Sadly, the board doesn’t do much – yet – but that doesn’t mean we’re not impressed. And [Mike]’s no stranger to miniaturization projects, of course; last year’s Open Hardware Summit badge was his brainchild.
Continue reading “A Coin Cell Powers This Tiny ESP32 Dev Board”
It is a bit of a paradox that we are storing more and more information digitally, yet every year more and more of it is becoming harder to access. Data on a variety of tapes and disks that were once common, is now trapped on media due to lack of hardware to read it. Do you have a ZIP drive? Do you have a computer that it will work with? Floppies are problem too. You might think you beat the system just by having a USB floppy drive. While these do exist, they typically won’t read oddball formats. That is, except for Flux Engine, an open source USB floppy drive.
The device uses a $15 Cypress development board and just some wiring (along with a 3.5 or 5.25 floppy drive, of course). Currently, the firmware only supports read only access to IBM standard disks and Acorn DFS/ADFS disks. It can also read and write Brother word processor disks. However, being open source, it could do more. The author, [David Given], is looking for Commodore 1541 and Apple CLV disks to borrow so he can get those working. He’s also offered to entertain other formats if you are willing to loan him a disk.
The software uses libusb and is known to work on Linux and Windows with Cygwin. It should also work with OSX. However, you will need a Windows box of some sort to build the Cypress firmware because the Cypress tools won’t work anywhere else. [David] wants to change processors because of this, but if he does, he’ll miss the PSoC function blocks, we are guessing.
The design is actually rather simple. The firmware only measures the time between flux transitions and sends them to the attached PC. All the heavy lifting occurs on the PC, which means it should be pretty easy to analyze and decode new formats. While writing is possible, it appears there is more work that needs to happen to make it reliable. [David] comments that you really need a real drive to test your writing with so you don’t write things only you can read back. Makes sense.
This certainly is more user-friendly than the last method we looked at. We had to wonder if [David] has thought about 8-inch floppies.