Easier UART to 1-Wire Interface

The 1-Wire protocol is usually found in temperature sensors, but you’ll also find it in chips ranging from load sensors, a battery sensor and LED driver that is oddly yet officially called a ‘gas gauge’, and iButtons. It’s a protocol that has its niche, and there are a few interesting application notes for implementing the 1-wire protocol with a UART. Application notes are best practices, but [rawe] has figured out an even easier way to do this.

The standard way of reading 1-Wire sensors with a UART is to plop a pair of transistors and resistors on the Tx and Rx lines of the UART and connect them to the… one… wire on the 1-Wire device. [rawe]’s simplification of this is to get rid of the transistors and just plop a single 1N4148 diode in there.

This would of course be useless without the software to communicate with 1-Wire devices, and [rawe] has you covered there, too. There’s a small little command line tool that will talk to the usual 1-Wire temperature sensors. Both the circuit and the tool work with the most common USB to UART adapters.

Using HID Tricks to Drop Malicious Files

[Nikhil] has been experimenting with human interface devices (HID) in relation to security. We’ve seen in the past how HID can be exploited using inexpensive equipment. [Nikhil] has built his own simple device to drop malicious files onto target computers using HID technology.

The system runs on a Teensy 3.0. The Teensy is like a very small version of Arduino that has built-in functionality for emulating human interface devices, such as keyboards. This means that you can trick a computer into believing the Teensy is a keyboard. The computer will treat it as such, and the Teensy can enter keystrokes into the computer as though it were a human typing them. You can see how this might be a security problem.

[Nikhil’s] device uses a very simple trick to install files on a target machine. It simply opens up Powershell and runs a one-liner command. Generally, this commend will create a file based on input received from a web site controlled by the attacker. The script might download a trojan virus, or it might create a shortcut on the user’s desktop which will run a malicious script. The device can also create hot keys that will run a specific script every time the user presses that key.

Protecting from this type off attack can be difficult. Your primary option would be to strictly control USB devices, but this can be difficult to manage, especially in large organizations. Web filtering would also help in this specific case, since the attack relies on downloading files from the web. Your best bet might be to train users to not plug in any old USB device they find lying around. Regardless of the methodology, it’s important to know that this stuff is out there in the wild.

A Remote for CHDK Cameras Made Possible with Arduino

[AlxDroidDev] built himself a nice remote control box for CHDK-enabled cameras. If you haven’t heard of CHDK, it’s a pretty cool software modification for some Canon cameras. CHDK adds many new features to inexpensive cameras. In this case, [AlxDroidDev] is using a feature that allows the camera shutter to be activated via USB. CHDK can be run from the SD card, so no permanent modifications need to be made to the camera.

[AlxDroidDev’s] device runs off of an ATMega328p with Arduino. It operates from a 9V battery. The circuit contains an infrared receiver and also a Bluetooth module. This allows [AlxDroidDev] to control his camera using either method. The device interfaces to the camera using a standard USB connector and cable. It contains three LEDs, red, green, and blue. Each one indicates the status of a different function.

The Arduino uses Ken Shirrif’s IR Remote library to handle the infrared remote control functions. SoftwareSerial is used to connect to the Bluetooth module. The Arduino code has built-in functionality for both Canon and Nikon infrared remote controls. To control the camera via Bluetooth, [AlxDroidDev] built a custom Android application. The app can not only control the camera’s shutter, but it can also control the level of zoom.

DIY USB Stereo Headphone Amplifier

The biggest and best audiophile projects are usually huge tube amps, monstrous speaker cab builds, or something else equally impressive. It doesn’t always have to be that way, though, as [lowderd] demonstrates with a tiny DIY USB DAC build that turns a USB port into a headphone output.

In the Bad Old Days™ putting a DAC on a USB bus would require some rather fancy hardware and a good amount of skill. These days, you can just buy a single chip USB stereo DAC that still has very good specs. [lowderd] used the TI PCM2707 USB DAC, a chip that identifies as a USB Audio Class 1.0 device, so no drivers are needed for it to work in either Windows or OS X.

The circuit fits on a tiny PCB with a USB port on one side, a headphone jack on the other, and the chip and all related components in between. There are some pins on the chip that allow for volume, play/pause. and skip, but these pins were left unconnected for sake of simplicity.

The board was fabbed up at OSH Park, and the second revision of the case laser cut out of bamboo and acrylic by Ponoko. It’s a great looking little box, and something that fits right inside [lowderd]’s headphone case.

Sigzig data loggers ditch the noise while pimping the case

We ran into [Paul Allen] at CES. He was showing off Sigzig, a super-low noise data logger which his company is just rolling out.

IMG_20150107_174520A couple of years ago he worked on a standalone chemical sensor and had a few extra boards sitting around after the project was done. As any resourceful hacker will do, he reached for them as the closest and easiest solution when needing to log data as a quick test. It wasn’t for quite some time that he went back to try out commercially available loggers and found a problem in doing so.

The performance of off-the-shelf data loggers wasn’t doing it for [Paul’s] team. They kept having issues with the noise level found in the samples. Since he had been patching into the chemical sensor PCBs and getting better results, the impetus for a new product appeared.

The flagship 24-bit 8-channel Sigzig samples 0-5v with less than 1uV of noise. A less expensive 4-channel differential unit offers 18-bit with 10-12 uV of noise. They are targeting $199 and $399 price points for the two units. We asked about the sample rate in the video below. The smaller version shown here captures up to 240 samples per second. The big guy has the hardware potential to sample 30,000 times per second but since the data is continuously streaming over USB that rate is currently limited to much less.

Update: It has been pointed out in the comments that USB may not be the choke point for sample rate.

 

A SEGA Dreamcast Controller With a Built-in Screen

[Fibbef] was hard at work on a project for a build-off competition when he accidentally fried the circuit board. Not one to give up easily, he opted to start a new project with only two days left in the competition. He managed to modify a SEGA Dreamcast controller to hold a color screen in that short amount of time.

The Dreamcast controller’s shape is somewhat conducive to this type of mod. It already has a small window to ensure the view of the visual memory card is not obstructed. Unfortunately [Fibbef’s] screen was a bit too large for this window. That meant he would have to expand the controller and the circuit board.

After taking the controller apart, he desoldered the memory card connectors. He then cut the circuit board cleanly in half vertically. He had to re-wire all of the traces back together by hand. It turned out initially that he had messed something up and accidentally fried the right half of the controller. To fix it, he cut a second controller in half and soldered the two boards together.

With some more horizontal space to work with on the PCB side of things, [Fibbef] now needed to expand the controller’s housing. He cut the controller into several pieces, making sure to keep the start button centered for aesthetics. He then used duct tape to hold popsicle sticks in place to make up for the missing pieces of the case. All of the sticks were then covered with a thick layer of ABS cement to make for a more rigid enclosure. All of this ended up being covered in Bondo, a common trick in video game console mods. It was then sanded smooth and painted with black primer to make for a surprisingly nice finish.

The screen itself still needed a way to get power and a video signal. [Fibbef] built an adapter box to take both of these signals and pass them to the controller via a single cable. The box as a USB-A connector for power input, and a composite connector for video. There’s also a USB-B connector for the output signals. [Fibbef] uses a standard printer USB cable to send power and video signals to the controller. The end result looks great and serves to make the Dreamcast slightly more portable. Check out the demo video below to see it in action. Continue reading “A SEGA Dreamcast Controller With a Built-in Screen”

New Part Day: Three-dimensional USB Connectors

There’s an old joke that says USB cables do not exist in three-dimensional Euclidian space. Try to plug a USB cable in a socket, and the first try will always be wrong. Flip it, try to plug it in, and that will also be wrong. You will only succeed on the third try, and this is proof that USB connectors exist in higher planes of reality with arcane geometries. The joke is as old as the Pythagoreans, who venerated USB connectors as gods.

The waveform has collapsed, the gods profaned, and USB connectors that exist in only three dimensions have arrived. We’re talking, of course, about reversible USB Type A connector that will plug in the first time, every time. No need for electromancy or the “looking on the cable for the USB logo and plugging it in with that side up” method used by tech plebeians.

This discovery came after going through my daily roundup of crowdfunding press releases, eventually landing me on this idiotic project. It’s a USB charge cable that’s supposed to charge your phone twice as fast, despite the fact that charging speed is a function of current, and that’s determined by whatever you’re charging from, not the cable. Terrible idea, but they do have something interesting: a three-dimensional USB connector.

connUSBThe connector isn’t the brand new USB 3.1 Type C connector that will eventually find its way into phones, laptops, wearables of all types. This is your standard Type A USB plug you’ve known and loved for the past eighteen years. The difference here is that the chunky block of plastic that has made the common USB cable non-reversible for so many years is gone. In its place is a tiny strip of plastic that has contacts on both sides. Yes, it took nearly two decades for someone to figure out this would be a marketable idea.

While searching for a source for these three-dimensional USB connectors, the only source I could come up with was Wurth Elektronik, With Farnell/Element14 carrying a selection of connectors, a few available on Digikey, and some available on Mouser. There are even a few pre-made reversible cables available, with Tripp Lite leading the game right now.

For integrating one of these connectors into your build, there’s only one thing to watch out for: the pinout for these plugs is mirrored on each side of the thin strip of plastic going down the middle of the connector. This means your VCC and GND pins will be right next to each other, your D+ and D- signal pins right next to each other, and now you have to do your layout with eight pins instead of only four.

While it may not be groundbreaking and it makes for some confusing PCB layout work, but as told by a highly successful crowdfunding campaign, this can be a real feature for a product.

If you’ve recently come across a component, connector, or part that’s unique, interesting, or downright cool everyone should know about, send it on in and we’ll take a look at it.