Stove Alarm Keeps The Kitchen Safe

December 9, 2018 by Lewin Day 70 Comments

Gas cooktops have several benefits, being able to deliver heat near-instantly, while also being highly responsive when changing temperature. However, there are risks involved with both open flames and the potential of leaving the gas on with the burner unlit. After a couple of close calls, [Bob] developed a simple solution to this safety issue.

The round PCB sits neatly behind the knobs, affixed with double-sided tape.

Most commercial products in this space work by detecting the heat from the cooktop, however this does not help in the case of an unlit burner being left on. [Bob]’s solution was to develop a small round PCB that sits behind the oven knobs. Magnets are placed on the knobs, which hold a reed switch open when the knob is in the off position. When the knob is turned on, the reed switch closes, powering a small microcontroller which beeps at regular intervals to indicate the burner is on.

It’s a tidy solution to a common problem, which could help many people – especially the elderly or the forgetful. It integrates neatly into existing cooktops without requiring major modification, and [Bob] has made the plans available if you wish to roll your own.

On the other end of the scale, you might want an alarm on your freezer, too.

A Raspberry Pi Has This Pool Covered

December 2, 2018 by Jenny List 25 Comments

Far from being a tiled hole in the ground with a bit of water in it, a modern swimming pool boasts a complex array of subsystems designed to ensure your morning dip is as perfect as that you’d find on the sun-kissed beaches of your dream tropical isle. And as you might expect with such complex pieces of equipment in a domestic setting, they grow old, go wrong, and are expensive to fix.

[DrewBeer]’s pool had just such a problem. A decades-oldwired controller had failed, so rather than stump up a fortune for a refit, he created his own pool controller which exists under the watchful eye of a Raspberry Pi. The breadth of functionality is apparent from his write-up. In addition to the pump and heater you’d expect, he as a salt water system, environmental monitoring, and even an RTL-SDR to pull in readings from an RF floating temperature probe. It’s all exposed via a node.js API, and thus far has been running for over 6 months without mishap.

From where this is being written in the gloom of a damp November in a Northern Hemisphere maritime climate we can only envy [Drew] his pool and imagine it as perpetually deep blue and sparkling, invitingly cool against the heat of a summer’s day. If you have similar pool automation woes. perhaps you’d also like to look at this ESP8266 pool monitor, or another automation project using a Raspberry Pi.

Connect Your Electric Heater To The Internet (Easily And Cheaply)!

December 1, 2018 by Brian Benchoff 18 Comments

Winter has arrived, and by now most households should have moved on from incandescent bulbs, so we can’t heat ourselves that way. Avoiding the chill led [edent] to invest in an electric blanket. This isn’t any ordinary electric blanket — no, this is one connected to the Internet, powered by Alexa.

This is a project for [edent] and his wife, which complicates matters slightly due to the need for dual heating zones. Yes, dual-zone electric heating blankets exist (as do two electric blankets and sewing machines), but the real problem was finding a blanket that turned on when it was plugged in. Who would have thought a simple resistive heating element could be so complicated?

For the Internet-facing side of this project, [edent] is using a Meross smart plug and a Sonoff S20 smart plug. These are set up through to work with Alexa and configured as an ‘electric blanket’ group. Simply saying, “Alexa, switch on the electric blanket” turns on the bed.

There are a few problems in need of future improvement. Alexa doesn’t recognize voices, so saying ‘Turn on my side of the bed’ doesn’t work. The blanket also shuts off after an hour, but the plug sockets stay live. There’s also the possibility that hackers could break into this Alexa and burn down the house, but this is a device on the Internet; that sort of stuff virtually never happens.

You can check out the demo of the electric bed below.

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DIY Ovalia Chair Serves Your Futuristic Fantasies

November 25, 2018 by Lewin Day 16 Comments

The 1960s were a heady time, with both society and the language of design undergoing rapid changes over a short period. Back in 1968, Henrik Thor-Larsen exhibited his Ovalia egg chair for the first time, at the Scandinavian Furniture Fair. With original examples now antiques, and with even replicas being prohibitively expensive, it might just be worth considering building your own if you need to have one. Thankfully, [Talon Pascal] leads the way.

It’s a replica that’s built with accessible DIY tools and techniques. The frame is built up from plywood parts, cut out with a jigsaw. These are then assembled with glue and screws, forming two halves of the full-sized egg assembly. The exterior is then covered with thin strips of wood, as opposed to the fiberglass construction of the original. This is smoothed out with a judicious application of wood putty and plenty of sanding. The interior is then lined with foam before the chair is upholstered with red fabric. We’re not sure exactly how the trim ring is fitted, but it gives the chair a nice clean finished edge and rounds out the project nicely. There are even embedded speakers so you can chill out with some tunes in your ovaloid sanctuary.

It just goes to show that there’s value in the old adage – if you can’t buy it, build it! Perhaps, however, you’re outfitting the office – in which case, would something from the Porsche range suffice?

Beautiful Moving Origami Light Made From Scrap

November 22, 2018 by Tom Nardi 3 Comments

Whenever [MakerMan] hits our tip line with one of his creations, we know it’s going to be something special. His projects are almost exclusively built using scrap and salvaged components, and really serve as a reminder of what’s possible if you’re willing to open your mind a bit. Whether done out of thrift or necessity, he proves the old adage that one man’s trash is often another’s treasure.

We’ve come to expect mainly practical builds from [MakerMan], so the beautiful ceiling light which he refers to as a “Kinetic Chandelier”, is something of a change of pace. The computer controlled light is able to fold itself up like an umbrella while delivering a pleasing diffuse LED glow. He tells us it’s a prototype he’s building on commission for a client, and we’re going to go out on a limb and say he’s going to have a very satisfied customer with this one.

Like all of his builds, the Kinetic Chandelier is almost entirely built out of repurposed components. The support rods are rusty and bent when he found them, but after cutting them down to size and hitting them with a coat of spray paint you’d never suspect they weren’t purpose-made. The light’s “hub” is cut out of a chunk of steel with an angle grinder, and uses bits of bike chain for a flexible linkage.

Perhaps most impressive is his DIY capstan which is used to raise and lower the center of the light. [MakerMan] turns down an aluminum pulley on a lathe to fit the beefy gear motor, and then pairs that with a few idler pulleys held in place with bits of rebar welded together. It looks like something out of Mad Max, but it gets the job done.

Finally, he salvages the LED panels out of a couple of cheap work lights and welds up some more rebar to mount them to the capstan at the appropriate angle. This gives the light an impressive internal glow without a clear source when viewed from below, and really gives it an otherworldly appearance.

This isn’t the first time we’ve seen a hacker put together their own chandelier, or even the first time we’ve seen it done with scrap parts. But what [MakerMan] has put together here may well be the most objectively attractive one we’ve seen so far.

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Retro Wall Phone Becomes A Doorbell, And So Much More

November 20, 2018 by Dan Maloney 5 Comments

We have to admit that this retasked retro phone wins on style points alone. The fact that it’s filled with so much functionality is icing on the cake.

The way [SuperKris] describes his build sounds like a classic case of feature creep. Version 1 was to be a simple doorbell, but [SuperKris] would soon learn that one does not simply replace an existing bell with a phone and get results. He did some research and found that the ringer inside the bakelite beauty needs much more voltage than the standard doorbell transformer supplies, so he designed a little H-bridge circuit to drive the solenoids. A few rounds of “while I’m at it” later, the phone was stuffed with electronics, including an Arduino and an NFR24 radio module that lets it connect to Domoticz, a home automation system. The phone’s rotary dial can now control up to 10 events and respond to alarms and alerts with different ring patterns. And, oh yes – it’s a doorbell too.

In general, we prefer to see old equipment restored rather than gutted and filled with new electronics. But we can certainly get behind any effort to retask old phones with no real place in modern telecommunications. We’ve seen a few of these before, like this desk telephone that can make cell calls.

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The Lost Art Of Steam Heating

November 18, 2018 by Maya Posch 51 Comments

We got pointed by [packrat] to a 2015 presentation by [Dan Holohan] on the history and art of steam heating systems. At the advent of central heating systems for entire buildings, steam was used instead of water or air for the transport medium. These systems were installed in landmark buildings including the Empire State Building, which still use them to this day.

A major advantage of steam-based heating system is that no pump is required: the steam will naturally rise up through the piping, condenses and returns to the origin. This can be implemented as a single pipe where condensation returns through the same pipe as the steam, or a two-pipe system where the condensate returns through its own pipe.

In the presentation, Dan walks us through his experiences working on many of these steam heating systems in major US buildings, the types of systems, fixes implemented by engineers long since dead and the particularities of maintaining these systems.

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