Amazon Dash Reboots Your Pi

We all know feature creep can be a problem in almost any project. A simple idea can often become unusable if a project’s scope isn’t clearly defined in the beginning. However, the opposite problem sometimes presents itself: forgetting to include a key feature. [Zach] had this problem when he built a Raspberry Pi magic mirror and forgot to build a physical reset/shutoff switch. Luckily he had a spare Amazon Dash button and re-purposed it for use with his Pi.

The Raspberry Pi doesn’t include its own on/off switch. Without installing one yourself, the only way to turn off the device (without access to the terminal) is to unplug it, which can easily corrupt data on the SD card. Since [Zach]’s mirror was already complete, he didn’t want to take the entire thing apart just to install a button. There’s already a whole host of applications for the Dash button, so with a little Node.js work on the Raspberry Pi he was able to configure a remote-reset button for his mirror.

This is a similar problem for most Raspberry Pi owners, so if you want to follow [Zach]’s work he has done a great job detailing his process on his project site. If you’re looking for other uses for these convenient network-enabled buttons, he also links to a Github site with lots of other projects. This pizza button is probably our favorite, though.

NFC Tags Add Old-School Functionality to New Phone

Back in the day, we had smartphones with physical buttons. Not just power, volume, and maybe another button on the front. Whole, slide-out QWERTY keyboards right on the underside of the phone. It was a lawless wasteland, but for those who yearn for the wild-west days of the late 2000s, [Liviu] has recreated the shortcut buttons that used to exist on the tops of these keyboards for modern-day smartphones.

There were lots of phones that had shortcut keys on their keyboards, but [Liviu] enjoyed using the ones that allowed him to switch between applications (or “apps” as the kids are saying these days) such as the calendar, the browser, or the mail client. To recreate this, he went with a few NFC tags. These devices are easily programmed via a number of apps from your app store of choice, and can be placed essentially anywhere. In order to make them visible to the phone at any time, though, he placed the tags inside a clear plastic case for his phone and can now use them anytime.

If you’ve never used or programmed an NFC tag, this would be a great project to get yourself acquainted with how they operate. Plus, you could easily upgrade this project to allow the tags to do any number of other things. You can take projects like this as far as you want.

Continue reading “NFC Tags Add Old-School Functionality to New Phone”

Alarm Notifies the Office When the Coffee is Ready

[Stian] thought it would be nice if his coworkers could be electronically notified when the latest batch of coffee is ready. He ended up building an inexpensive coffee alarm system to do exactly that. When the coffee is done, the brewer can press a giant button to notify the rest of the office that it’s time for a cuppa joe.

[Stian’s] first project requirement was to activate the system using a big physical button. He chose a button from Sparkfun, although he ended up modifying it to better suit his needs. The original button came with a single LED built-in. This wasn’t enough for [Stian], so he added two more LEDs. All three LEDs are driven by a ULN2003A NPN transistor array. Now he can flash them in sequence to make a simple animation.

This momentary push button supplies power to a ESP8266 microcontroller using a soft latch power switch. When the momentary switch is pressed, it supplies power to the latch. The latch then powers up the main circuit and continues supplying power even when the push button is released. The reason for this power trickery is to conserve power from the 18650 li-on battery.

The core functionality of the alarm uses a combination of physical hardware and two cloud-based services. The ESP8266 was chosen because it includes a built-in WiFi chip and it only costs five dollars. The microcontroller is configured to connect to the WiFi network with the push of a button. The device also monitors the giant alarm button.

When the button is pressed, it sends an HTTP request to a custom clojure app running on a cloud service called Heroku. The clojure app then stores brewing information in a database and sends a notification to the Slack cloud service. Slack is a sort of project management app that allows multiple users to work on projects and communicate easier over the internet. [Stian] has tapped into it in order to send the actual text notification to his coworkers to let them know that the coffee is ready. Be sure to watch the demo video below. Continue reading “Alarm Notifies the Office When the Coffee is Ready”

Adding A Backlight To A Cheap Multimeter

We don’t all need super high quality electronic testing gear. Sometimes second-hand or inexpensive equipment is accurate enough to get the job done. Though it can be a bit annoying to miss out on some of those “luxury” features. [Ekriirke] had this problem with his cheap multimeter. He wished the LCD screen had a backlight for easier visibility, so rather than upgrade to a more expensive unit he just added one himself.

After opening up the multimeter [Ekriirke] found that it ran on a single 12V battery. He realized that the simplest thing to do would be to wire up four white LEDs in series. The four LEDs were arranged within the case off to each side of the LCD, one in each corner. The leads were bent at 90 degree angles and soldered together “dead bug” style. Thin strips of copper foil tape were attached to the PCB in such a way that the anode and cathode from the LEDs would make contact when the case was closed back up.

The tape wraps around to the other side of the PCB where there was more room for the next piece of the circuit. A capacitor, resistor, and transistor are used in conjunction with a momentary switch. This circuit allows [Ekriirke] to turn on the light for about ten seconds by pressing the button one time. The circuit also runs through the meter’s dial switch, preventing the LEDs from being turned on while the meter itself is turned off.

[via Reddit]

Dial is a Simple and Effective Wireless Media Controller

[Patrick] was looking for an easier way to control music and movies on his computer from across the room. There is a huge amount of remote control products that could be purchased to do this, but as a hacker [Patrick] wanted to make something himself. He calls his creation, “Dial” and it’s a simple but elegant solution to the problem.

Dial looks like a small cylindrical container that sits on a flat surface. It’s actually split into a top and bottom cylinder. The bottom acts as a base and stays stationary while the top acts as a dial and a push button. The case was designed in SOLIDWORKS and printed on a 3D printer.

The Dial runs on an Arduino Pro mini with a Bluetooth module. The original prototype used Bluetooth 2.0 and required a recharge after about a day. The latest version uses the Bluetooth low energy spec and can reportedly last several weeks on a single charge. Once the LiPo battery dies, it can be recharged easily once plugged into a USB port.

The mechanical component of the dial is actually an off-the-shelf rotary encoder. The encoder included a built-in push button to make things easier. The firmware is able to detect rotation in either direction, a button press, a double press, and a press-and-hold. This gives five different possible functions.

[Patrick] wrote two pieces of software to handle interaction with the Dial. The first is a C program to deal with the Bluetooth communication. The second is actually a set of Apple scripts to actually handle interaction between the Dial and the various media programs on his computer. This allows the user to more easily write their own scripts for whatever software they want. While this may have read like a product review, the Dial is actually open source! Continue reading “Dial is a Simple and Effective Wireless Media Controller”

Garage Clicker Dashboard Integration


Vehicles with the highest level of trim package sometimes come with the ability to learn garage door opener codes. Less costly offerings lack that feature as well as others bells and whistles, leaving blank plates where fancy buttons would have been. [JiggMcFigg] makes the best of this situation by gutting his garage remote and hiding it behind a button blank.

One thing that raised an eyebrow is the coin cell battery holder you can make out on the size-check image shown to the left. But really, these remotes must drain their batteries at a rate nearly the same as an unused battery so why complicate the hack? A holder was soldered onto the board, and jumper wires were soldered to the push button added to the blank plate. This type of utilitarian button is much more satisfying to use than those fancy-pants silk-screen molded-plastic types anyway!

Of course you could go the other way with this hack. [JiggMcFigg] started out with the problem of losing the remotes in the mess of the car. You could retrofit it with a huge button to make it harder to misplace.

Hackaday Links: October 13, 2013


This week’s post on core rope ROM was pretty popular. [Joey] wrote in with a book recommendation for those that found the project interesting. Digital Apollo discusses the technology which NASA built into the guidance computer. That was also the subject of a recent Retrotechtacular.

A few members of the Vancouver Hack Space came up with their own take on the Word Clock. It uses an old monitor, a laser-cut bezel, and Javascript to light up the correct characters.

When we last looked in on [Vincent’s] plywood stool project he had branched out into plywood folding chairs as well. Here’s two updates on his progress.

This one’s just silly. To keep up with his wife on exercise goals, this guy cheated using a reciprocating saw to spoof his exercise. Tape the FitBit to the saw blade, clamp the saw to the workbench, and then let her rip! [via Reddit]

[Harrison] wrote into share the Arduino button library he developed. It is designed to allow detection of multiple types of button events without blocking other operations. He came up with the project to use with his motorcycle hacking.

It looks like [Bertho] has kitted up his Executive Decision Maker. We first saw this as a perfboard project a couple of years ago.

And finally, [Bob Alexander] makes your hard drive clock look puny. His uses the platter from a 40-year-old mainframe hard drive.