You’ve Got Mail?

November 30, 2019 by Richard Baguley 24 Comments

Life is full of tough decisions, such as deciding whether you want to go to the end of the drive to check if the mail has arrived. These questions are made even more arduous in the winter months, but [Catpin] has a solution. The Mail Box Alert uses an Electric Imp, a solar panel and a proximity sensor to let you know if you’ve got mail.

It’s a neat build, with the brains provided by that Electric Imp which handles most of the heavy lifting. This wakes up every five minutes and checks whether the status of a small proximity sensor has changed. If it has, it pings a website. The unit sits at the bottom of the postbox, so if your friendly neighborhood post person has put in any letters, it will have changed. The Imp is powered by a small battery, which is in turn charged by a solar panel. That means that it doesn’t require any power cables or other wiring, as long as it is in the range of WiFi. With the addition of a 15-hours overnight deep sleep, [Catpin] found that the whole thing could be run from a couple of 18650 LiPo batteries.

Perhaps the most interesting part of the writeup was discussing the problems that he found with the build, such as the fact that a LiPo battery won’t perform that well in a Wisconsin winter. So, this was replaced with a Lithium Iron Phosphate battery that should be a bit more tolerant of the chill. There is also a writeup on how to create the same project using an ESP8266 if required.

A Division In Voltage Standards

November 28, 2019 by Sharon Lin 152 Comments

During my recent trip to Europe, I found out that converters were not as commonly sold as adapters, and for a good reason. The majority of the world receives 220-240 V single phase voltage at 50-60 Hz with the surprisingly small number of exceptions being Canada, Colombia, Japan, Taiwan, the United States, Venezuela, and several other nations in the Caribbean and Central America.

While the majority of countries have one defined plug type, several countries in Latin America, Africa, and Asia use a collection of incompatible plugs for different wall outlets, which requires a number of adapters depending on the region traveled.

Although there is a fair degree of standardization among most countries with regards to the voltage used for domestic appliances, what has caused the rift between the 220-240 V standard and the 100-127 V standards used in the remaining nations?

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Gaze Deeply Into These Infinity Mirror Coasters

November 21, 2019 by Tom Nardi 11 Comments

Infinity mirrors have been gaining in popularity recently, thanks in no small part to the availability of low-cost RGB LED strips to line them with. Generally such pieces are limited to wall art, or the occasional table build, which is what makes these infinity mirror drink coasters from [MnMakerMan] so unique.

Built from an ATtiny85 and a WS2812B LED strip nestled into a 3D printed enclosure, these coasters are relatively cheap and easy to assemble should you want to run a few off before the holiday party season. [MnMakerMan] mentions the LEDs can consume a decent amount of energy, so he’s included a module to allow recharging of the internal 3.7 V 1500 mAh battery over USB.

Of course, a couple of PLA pieces and a custom PCB doesn’t make an infinity mirror. To achieve the desired effect, he’s created a stack consisting of a 4″ glass mirror, a 1/8″ thick plexiglass disc, and one-way mirror tint film. The WS2812B strip mounted along the circumference lights up the void between the two surfaces, and produces a respectable sense of depth that can be seen in the video after the break.

This isn’t the first high-tech piece of surface protection we’ve seen around these parts, as some very nice wirelessly charged supercapacitor coasters were entered into the 2019 Hackaday Prize. Of course, if you’re of the opinion that coasters should remain as cheap as possible, we’ve seen a number of automated attempts to add some flair to the classic paperboard discs.

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Detecting Water Before It’s Too Late

November 14, 2019 by Gerrit Coetzee 25 Comments

[mcu_nerd] is like any engineer, which is why his problem of an occasionally leaky water heater sure looks like a research project with no end in sight. Sure there’s probably a commercial product out there that can be had for half the cost and a few clicks of the mouse, but what’s the point in actually solving the problem?

His log starts with research into detecting low battery voltages. Then it was a quick exploration in designing low-power circuits. When the Flexible PCB contest came along, he realized that there was a chance to design a better electrode, and he ended up winning one of the vouchers; which is where he’s at now.

It’s definitely a work in progress, and if anything it’s just a quick five minute read and an opportunity to commiserate with another wayward soul. We do like his clever use of a tealite candle tin as both the second electrode and case for his water detection circuit. There are also some KiCad files and code.

LCD Panel Lamp Shade Makes For Eye-Catching Lighting

November 11, 2019 by Jenny List 14 Comments

At first sight, [Kyle]’s Elroy lamp is simply an attractive piece of modern-styled interior furnishing; its clean lines, wood grain, and contemporary patterning being an asset to the room. But when he pulls out his phone, things change. Because this lamp hides a secret: at its heart may be a standard LED bulb, but the shade conceals four LCD screens driven by an Nvidia Jetson. These can be controlled through a web app to display a variety of textures, completing the effect.

This is not however simply a set of laptop screens bolted to a lampshade. The screens started life in laptops sure enough, but have since had their reflective backing removed to create a transparent LCD panel. Then an appropriate diffuser had to be found, which after much experimentation became a composite including more than one textured paper. Finally the whole was enclosed in an attractive wooden lamp frame and became part of the furniture. We like it, both as an aesthetically pleasing lamp and as a genuine departure from the norm.

This isn’t the first eye-catching lampshade we’ve brought you, but it’s certainly raised the bar. You can see it in action in the video below the break.

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Found Footage: Elliot Williams Talks Nexus Technologies

November 7, 2019 by Tom Nardi 25 Comments

Back at the 2017 Superconference, Hackaday Managing Editor Elliot Williams started his talk about the so-called “Internet of Things” by explaining the only part he doesn’t like about the idea is the Internet… and the things. It’s a statement that most of us would still agree with today. If anything, the situation has gotten worse in the intervening years. Commercial smart gadgets are now cheaper and more plentiful than they’ve ever been, but it seems like precious little has been done to improve their inherent privacy and security issues.

But his talk doesn’t serve to bash the companies producing these devices or even the services that ultimately folded and left their customers with neigh useless gadgets. That’s not his style. The central theme of “Nexus Technologies: Or How I Learned to Love WiFi” is that a smart home can be wonderful thing, assuming it works the way you want it to. Elliot argues that between low-cost modular hardware and open source software, the average hacker has everything they need to build their own self-contained home automation ecosystem. One that’s not only cheaper than what they’re selling at the Big Box electronics store, but also doesn’t invite any of the corporate giants to the party.

Of course, it wasn’t always so. A decade ago it would have been all but impossible, and five years ago it would have been too expensive to be practical. As Elliot details his journey towards a truly personal smart home, he explains the advances in hardware and software that have made it not just possible on the DIY level, but approachable. The real takeaway is that once more people realize how cheap and easy it is to roll your own smart home gadgets, they may end up more than willing to kick Big Brother to the curb and do IoT on their own terms.

This previously unpublished recording somehow slipped between the cracks of the editing room floor but upon recent discovery, it’s still just as relevant today. Take a look at Elliot’s view on Nexus Technologies, then join us after the break for a deeper dive. Make sure to subscribe to Hackaday’s YouTube channel to get in on the 2019 Hackaday Superconference live stream starting Saturday, November 16th.

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Router Rebooter Without The Effort

November 2, 2019 by Jenny List 67 Comments

It’s one of the rituals of our age, rebooting the family router when the bandwidth falters. Flip the power, and after half a minute or so your YouTube video starts up again. Consumer-grade router hardware is not the most reliable computing equipment you will own, as [Nick Sayer] found out when the router at his vacation home wasn’t reliable enough to support his remote monitoring equipment. His solution is an auto-reboot device, that power-cycles the offending device on command.

An obvious method might be to switch the mains supply, but instead he’s taken the simpler option of switching the DC from the router’s wall wart power supply with a cunning arrangement of three MOSFETs to keep the router defaulting to on under all conditions except when it is commanded to power down by the ATtiny microcontroller overseeing it. This chip provides extra fail-safe and debouncing functions to ensure no accidental rebooting.

Driving the circuit is a Raspberry Pi that handles the house monitoring, on which a Python script checks for Internet access and asks for a reboot if there is none. For extra safety it requires access to be down for a sustained period before doing so in case of a router firmware upgrade.

This isn’t the first router rebooter, for a mains-switching ESP8266 take a look at this one.

Router picture: Asim18 [CC BY-SA 3.0]