Electronic Candle Charges Inductively

June 28, 2019 by Lewin Day 1 Comment

Humans like things that look like other things. A great example are faux LED tea light candles, with a plastic “flame” and flickering orange LED to recreate the effect of their waxy brethren. [gzumwalt] wanted to take the concept a little further, however, and got down to work.

The design harvests the orange LED and flame lens from an existing LED candle, but the rest is all original. [gzumwalt] printed a full-size candle, and fitted it with inductive charging hardware and a lithium-polymer battery. A corresponding charging base is used to supply power to the candle when it’s not in use. This is all handled automatically, with neodymium magnets used to activate reed switches to turn the charger on and the LED off.

It’s a tidy build that can be easily replicated with a 3D printer and some off-the-shelf parts. It’s also less wasteful than using disposable batteries, and safer than using real candles – so if you find yourself routinely shooting candle scenes in your budget film studio, it might be worth printing up a set of these.

LED candles range from the basic to the extreme – we’ve seen builds so realistic, you can light them with a match.

You’re Sitting On An Engineering Masterpiece: Chairs As A Design Challenge

June 25, 2019 by Jenny List 26 Comments

If you move as a hardware hacker through the sometimes surprisingly similar world of artists, craftspeople, designers, blacksmiths, and even architects, there’s one piece of work that you will see time and time again as an object that exerts a curious fascination. It seems that designing and building a chair is a rite of passage, and not just a simple chair, but in many cases an interesting chair.

An American-made Windsor chair from the turn of the 19th century. Los Angeles County Museum of Art [Public domain]

Some of the most iconic seating designs that you will be instantly familiar with through countless mass-produced imitations began their lives as one-off design exercises. Yet we rarely see them in our community of hackers and makers, a search turns up only a couple of examples. This is surprising, not least because there is more than meets the eye to this particular piece of furniture. Your simple seat can be a surprisingly complex challenge.

Moving Charis From Artisan to Mass Market

The new materials and mass production techniques of the 19th and 20th centuries have brought high-end design into the hands of the masses, but while wealthy homes in earlier centuries had high-quality bespoke furniture in the style of the day, the traditional furniture of the masses was hand-made in the same way for centuries often to a particular style dependent on the region in which it was produced.

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Let A Spooky Owl Tell You The Weather

June 18, 2019 by Jenny List 2 Comments

There can be few readers who were young in the 1970s who did not want to share in the adventures of the fearless animated ghost-hunting young crime-fighters of Scooby-Doo. What do you remember from the series though? The Mystery Machine van? Scooby snacks? Or perhaps the improbably haunted theme parks whose owners would have got away with it if it hadn’t been for those pesky kids? For [Alex Shakespeare] it seems to have been the trope of haunted pictures whose subject’s eyes would follow the protagonists around the room, because when he made a wall-mounted weather indicator he gave it an owl with eyes doing just that.

The weather part of the device is straightforward enough, an ESP8266 board drives a set of servos that move dial indicators according to data from the Dark Sky API. The owl’s moving googly eyes are the party piece though, for them the ESP takes input from an Adafruit AMG8833 thermal sensor array and drives a servo and lever arrangement to do the moving. Finally, the thermal camera’s output is available to see on the ESP’s web server. All the details of the project can be found via a GitHub repository.

The result is shown in the video below the break, and as you might expect in the spirit of its inspiration it’s more comedic than haunting. But maybe there’s the root of the popularity of artworks that follow the viewer, of which this is merely the latest in a long line.

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HestiaPi: A Stylish Open Hardware Thermostat

June 11, 2019 by Tom Nardi 20 Comments

A common complaint about open hardware and software is that the aesthetic aspects of the projects often leave something to be desired. This isn’t wholly surprising, as the type of hackers who are building these things tend to be more concerned with how well they work than what they look like. But there’s certainly nothing wrong with putting a little polish on a well designed system, especially if you want “normal” people to get excited about it.

For a perfect example, look no further than the HestiaPi Touch. This entry into the 2019 Hackaday Prize promises to deliver all the home automation advantages of something like Google’s Nest “smart” thermostat without running the risk of your data being sold to the highest bidder. But even if we take our tinfoil hat out of the equation, it’s a very slick piece of hardware from a functional and visual standpoint.

As you probably guessed from the name, the thermostat is powered by the Raspberry Pi Zero, which is connected to a custom PCB that includes a couple of relays and a connector for a BME280 environmental sensor. The clever design of the 3D printed case means that the 3.5 inch touch screen LCD on the front can connect directly to the Pi’s GPIO header when everything is buttoned up.

Of course, the hardware is only half the equation. To get the HestiaPi Touch talking to all the other smart gadgets in your life, it leverages the wildly popular OpenHAB platform. As demonstrated in the video after the break, this allows you to use the HestiaPi and its mobile companion application to not only control your home’s heating and air conditioning systems, but pretty much anything else you can think of.

The HestiaPi Touch has already blown past its funding goal on Crowd Supply, and the team is hard at work refining the hardware and software elements of the product; including looking at ways to utilize the unique honeycomb shape of the 3D printed enclosure to link it to other add-on modules.

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Smarten Up Your Air Conditioning With The ESP8266

June 11, 2019 by Tom Nardi 14 Comments

If you’re looking for “smart” home appliances, there’s no shortage of options on the market. Even relatively low-end gadgets are jumping on the Internet of Things bandwagon these days (for better or for worse). But what if you’re not looking to purchase a brand new major appliance right now? In that case, you might be interested in seeing how [Giulio Pons] added some high-tech features to his existing air conditioner on the cheap.

Since his AC unit had an infrared remote control, the first thing [Giulio] needed to do was come up with a way to emulate it. An easy enough project using the ESP8266 and an IR LED, especially when he found that somebody had already written a IR communications library for his particular brand of AC. From there, he could start tacking on sensors and functionality.

With the addition of a DHT11 sensor, [Giulio] can have the AC turn on and off based on the current room temperature. It also gives him an easy way to verify the AC is actually on and operating. By checking to see if the room starts cooling off after sending the IR command to start the AC, his software can determine whether it should try resending the code, or maybe send a notification to alert him that something doesn’t seem right. Of course, it wouldn’t be a proper ESP8266 project without some Internet connectivity, so he’s also created a smartphone application that lets him control the system while away from home.

Now admittedly nothing in this project is exactly new, we’ve seen plenty of hackers switch on their AC with the ESP8266 at this point. But what we particularly liked was how well thought out and documented the whole process was. The rationale behind each decision is explained, and he even documented things like his network topology to help illustrate how the whole system comes together. Even if the techniques are well known by many of us, this is the kind of project documentation that makes it accessible to newcomers. Our hats off to [Giulio] for going the extra mile.

In the past we’ve seen a similar project that allowed you to control your AC from Slack, and our very own [Maya Posch] took us on a whirlwind tour of the very impressive ESP8266-powered environmental monitoring system she helped develop.

Protect Your Coffee Machine With A Filter Monitor

June 9, 2019 by Jenny List 16 Comments

Coffee machines are delicate instruments, likely to be damaged by limescale. Thus they will often have a filter present, but filters have a limited capacity of water upon which they can be effective. At Make Bournemouth, they have approached the problem of when to change filters on their coffee machine by applying a bit of high-tech.

The water passing through the filter is monitored by a couple of DFRobot TDS modules, a flow meter, and a DS18B20 temperature sensor. The data from these is fed into an ESP32 dev board, which makes it available by a web interface for handy accessibility through a smartphone. It can then be used to work out how much of the filter’s capacity has been used, and indicate when a replacement is needed. All the code is available in a GitHub repository, and with luck now Bournemouth’s hackerspace will never see the coffee machine succumb to limescale.

Of course, this isn’t the first coffee maker water hack we’ve brought you. A year or two ago we told you about somebody making their pod coffee maker auto-fill too.

A Sonoff Switch Repurposed As A Thermostat

May 25, 2019 by Jenny List 14 Comments

Underfloor heating is a wonderfully luxurious touch for a bedroom and en-suite bathroom, and [Andy] had it fitted so that he could experience the joy of walking on a toasty-warm floor in the morning. Unfortunately after about a year it stopped working and the culprit proved to be its thermostat. A replacement was eye-wateringly expensive, so he produced his own using an ESP8266-powered Sonoff wireless switch.

The thermostat has a thermistor as its temperature sensor, embedded in the floor itself. This could be brought to the ESP’s solitary ADC pin, but not without a few challenges along the way. The Sonoff doesn’t expose the pin, so some very fine soldering was the first requirement. A simple voltage divider allowed the pin to be fed, but through it he made the unfortunate discovery that the ESP’s analogue input has a surprisingly low voltage range. A new divider tying it to ground solved the problem, and he was good to go.

Rather than using an off-the-shelf firmware he created his own, and with a bit of board hacking he was able to hard wire the mains cabling and use one set of Sonoff terminals as a sensor connector. The whole fit neatly inside an electrical fitting box, so he’s back once more to toasty-warm feet.

This isn’t the first ESP thermostat we’ve featured, nor will it be the last. Here’s a particularly nice build from 2017.