Protect Yourself — And Your Project — While Working With Mains Power

June 5, 2019 by Ted Yapo 33 Comments

When debugging ordinary low-voltage circuitry, you’re pretty safe: unless you have some really power-hungry devices that need a ton of current, there aren’t that many truly bad things that can happen, so you can take a lot of liberties with electrical-safety rules. With mains-powered devices, you don’t have this luxury, and a lack of knowledge, sloppy work practices, or simple mistakes can cost you — and your project — dearly. While you still need to know what you’re doing and use the requisite caution, [Yann Guidon]’s latest project — and entry in the 2019 Hackaday Prize — a mains protection box, might keep simple mistakes from becoming a disaster.

There are a number of precautions you can take when working with mains power. We’ve all used the simple in-line power strip so you can quickly switch off the current, but [Yann] has included a number of devices that can be configured in different ways to experiment with mains-powered devices safely. Built into a sturdy open-topped wooden box with carry handles, the project evokes the traditional breadboard in appearance and functionality. A number of different devices are included, which could be re-configured into different topologies if needed.

[Yann] included an isolation transformer, which can be useful not only for protection against shock in case of accidentally grounding, but also for noise suppression. There is also a variac, which allows the output voltage to be adjusted over a wide range for testing. Of course, circuit breakers are a must, and current and voltage meters keep you informed about what’s going on. A big, easy-to-access switch cuts the power quickly when needed.

The (maybe) final touch is an adjustable output current limit, which is still a work in progress. Built around a current-monitoring relay and a DPDT relay wired as a latch, this allows the output to be disconnected if it draws more than a specified current, equivalent to between 10 W and 100 W. This is the perfect thing for initial testing of new projects.

So, if you’re thinking of working on mains-powered projects, have a close look at what [Yann] has assembled, and learn proper safety procedures before you begin. One place to start is with a great series by our own Jenny List about mains safety: part one and part two. Stay safe out there!

Simple Arduino Universal Remote Control

June 4, 2019 by Tom Nardi 11 Comments

The infrared remote control might not hold the seat of honor in the average home theater setup that it once enjoyed, but it’s not quite out to pasture yet. After all, what are you going to use to stop Netflix once the Chromecast invariably disconnects from your phone? As long as there are devices out there that will respond to commands blasted their way via an IR LED, hackers will be looking to get in on the action.

In an effort to make IR remote hacking just a bit easier, [sjm4306] has submitted his Remoteduino for the 2019 Hackaday Prize. With this handy tool in your arsenal, you can focus on developing the software side of your next IR remote project without worry about the hardware. Just upload your code, and get clicking.

As you might imagine, the design is rather simple. On the front edge of the PCB you’ve got the prerequisite IR LED, and a healthy supply of tactile buttons that your code can use as input. The remote features a fairly standard layout on the top half, complete with silkscreened labels for the common functions, but below that [sjm4306] has packed in six general purpose buttons that can be used for whatever you like.

The Remoteduino is powered by an ATmega328P, and the whole thing runs on a CR2032 cell mounted on the backside. [sjm4306] mentions in his write-up on Hackaday.io that battery life was always a consideration during development of the Remoteduino, so he’s made a few energy-saving considerations. Using the internal 8 MHz oscillator instead of an external crystal shaved a bit off the top, and the aggressive sleep routines got him the rest of the way. In testing, he estimates the battery should last a few years even with daily use.

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A Work Light For Hacker Events

May 31, 2019 by Jenny List No comments

If you’ve ever attended a hacker camp, you’ll know the problem of a field of tents lit only by the glow of laser illumination through the haze and set to the distant thump of electronic dance music. You need to complete that project, but the sun’s gone down and you didn’t have space in your pack to bring a floodlight.

In Days of Yore you might have stuck a flickering candle in an empty Club-Mate bottle and carried on, but this is the 21st century. [Jana Marie] has the solution for you, and instead of a candle, her Club-Mate bottle is topped a stack of LED-adorned PCBs with a lithium-ion battery providing a high intensity downlight. It’s more than just a simple light though, it features variable brightness and colour temperature through touch controls on the top surface, as well as the ability to charge extra 18650 cells. At its heart is an STM32F334 microcontroller with a nifty use of its onboard timer to drive a boost converter, and power input is via USB-C.

We first saw an early take on this project providing illumination for a bit of after-dark Hacky Racer fettling at last year’s EMF 2018 hacker camp, since then it has seen some revisions. It’s all open-source so you can give it a go yourself if you like it.

Linear CCDs Make For Better Cameras

May 30, 2019 by Brian Benchoff 28 Comments

Digital cameras have been around for forty years or so, and the first ones were built around CCDs. These were two-dimensional CCDs, and if you’ve ever looked inside a copier, scanner, or one of those weird handheld scanners from the 90s, you’ll find something entirely unlike what you’d see in a digital camera. Linear CCDs are exactly what they sound like — a single line of pixels. It’s great if you’re into spectroscopy, but these linear CCDs also have the advantage of having some crazy resolutions. A four-inch wide linear CCD will have thousands of pixels, and if you could somehow drag a linear CCD across an image, you would have a fantastic camera.

Many have tried, few have succeeded, and [heye.everts]’ linear CCD camera is the best attempt at making a linear CCD camera yet. It took a fuzzy picture of a tree, which is good enough for a proof of concept.

The linear CCD used in this project works something like an analog shift register. With a differential clock, you simply push values out of the CCD and feed them into an ADC. The driver board for this CCD uses a lot of current and the timings are a bit tricky but it does work with a Teensy 3.6. But that’s only one line of an image, you need to move that CCD too. For that, this project uses something resembling a homebrew CD drive. There’s a tiny stepper motor and a leadscrew dragging the CCD across the image plane. All of this is attached to the back of a Mamiya RZ67 camera body.

Does it work? Yes. Surprisingly yes. After a lot of work, an image of a tree was captured. This is an RGB CCD, and at the moment it’s only using one color channel, but it does work. It’s a proof of concept rendered in a 2000 x 3000 grayscale bitmap. The eventual goal is to build a 37.5 Megapixel medium format camera around this CCD, and the progress is looking great.

A Stylish Solution For Bike Navigation

May 29, 2019 by Tom Nardi 7 Comments

[André Biagioni] is developing an open hardware bicycle navigation device called Aurora that’s so gorgeous it just might be enough to get you pedaling your way to work. This slick frame-mounted device relays information to the user through a circular array of SK6812 RGB LEDs, allowing you to find out what you need to know with just a quick glance down. No screen to squint at or buttons to press.

The hardware has already gone through several revisions, which is exactly what we’d expect to see for an entry into the 2019 Hackaday Prize. The proof of concept that [André] zip-tied to the front of his bike might have worked, but it wasn’t exactly the epitome of industrial design. It was enough to let him see that the idea had merit, and from there he’s been working on miniaturizing the design.

So how does it work? The nRF52832-powered Aurora connects to your phone over Bluetooth, and relays turn-by-turn navigation information to you via the circular LED array. This prevents you from having to fumble with your phone, which [André] hopes will improve safety. When you’re not heading anywhere specific, Aurora can also function as a futuristic magnetic compass.

With what appears to be at least three revisions of the Aurora hardware already completed by the time [André] put the project up on Hackaday.io, we’re very interested in seeing where it goes from here. The theme for this year’s Hackaday Prize is moving past the one-off prototype stage and designing something that’s suitable for production, and so far we’d say the Aurora project is definitely rising to the challenge.

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One Arduino Handheld To Rule Them All

May 28, 2019 by Tom Nardi 9 Comments

There’s nothing quite as annoying as duplicated effort. Having to jump through the same hoops over and over again is a perfect way to burn yourself out, and might even keep you from tackling the project that’s been floating around in the back of your mind. [Alain Mauer] found that he’d build enough Arduino gadgets that were similar enough he could save himself some time by creating a standardized piece of hardware that he can load his code du jour on.

He’s come to call this device the Arduino Nano QP (which stands for Quick Project), and now it’s part of the 2019 Hackaday Prize. [Alain] doesn’t promise that it’s the perfect fit for everything, but estimates around 85% of the simple Arduino projects that he’s come up with could be realized on QP. This is thanks to the screw terminals on the bottom of the device which let you easily hook up any hardware that’s not already on the board.

The QP board itself has the ubiquitous 16×2 character LCD display (complete with contrast control trimmer), seven tactile buttons arranged in a vaguely Game Boy style layout, and of course a spot to solder on your Arduino Nano. All of which is protected by a very slick laser cut acrylic case, complete with retained buttons and etched labels.

We’ve seen no shortage of handheld Arduino devices, but we have to admit, something about the utilitarian nature of this one has us intrigued. We wouldn’t mind having one of these laying around the lab next time we want to do a quick test.

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Eurorack Synth Module Runs On ESP32

May 24, 2019 by Lewin Day 8 Comments

The ESP32 is well known for both its wireless communication abilities, as well as the serious amount of processing power it possesses for a microcontroller platform. [Robert Manzke] has leveraged the hardware to produce a Eurorack audio synthesis platform with some serious capabilities.

Starting out as a benchmarking project, [Robert] combined the ESP32 with an WM8731 CODEC chip to handle audio, and an MCP3208 analog-to-digital converter. This gives the platform stereo audio, and the ability to handle eight control-voltage inputs.

The resulting hardware came together into what [Robert] calls the CTAG Strämpler. It’s a sampling-based synthesizer, with a wide feature set for some serious sonic fun. On top of all the usual bells and whistles, it features the ability to connect to the freesound.org database over the Internet, thanks to the ESP’s WiFi connection. This means that new samples can be pulled directly into the synth through its LCD screen interface.

With the amount of power and peripherals packed into the ESP32, it was only a matter of time before we saw it used in some truly impressive audio projects. It’s got the grunt to do some pretty impressive gaming, too. Video after the break.