Hack My House: UL Certification And Turning The Lights On With An ESP8266

April 22, 2019 by 48 Comments

It’s hard to imagine a smart house without smart lighting. Maybe it’s laziness, but the ability to turn a light on or off without walking over to the switch is a must-have, particularly once the lap is occupied by a sleeping infant. It’s tempting to just stuff a relay in the electrical boxes and control them with a Raspberry Pi or micro-controller GPIO. While tempting, get it wrong and you have a real fire hazard. A better option is one of the integrated WiFi switches. Sonoff is probably the most well known brand, producing a whole line of devices based on the ESP8266. These devices are powered from mains power and connect to your network via WiFi. One disadvantage of Sonoff devices is they only work when connected to Sonoff’s cloud.

Light switches locked in to a cloud provider are simply not acceptable. Enter Tasmota, which we’ve covered before. Tasmota is an open source firmware, designed specifically for Sonoff switches, but supporting a wide range of ESP8266 based devices. Tasmota doesn’t connect to any cloud providers unless you tell it to, and can be completely controlled from within a local network.

Certifications, Liability, and More

We’re well acquainted with some of the pitfalls of imported electronics, but one of the lesser known problems is the lack of certification. In the United States, there are several nationally recognized testing laboratories: Underwriters Laboratories (UL) and Intertek (ETL) are the most prominent. Many  imported electronic devices, including Sonoff devices, do not have either of these certifications. The problem with this is liability, should the worst ever happen and an electrical fire break out. The Internet abounds with various opinions on the importance of the certification — a missing certification mark is somewhere between meaningless and a total hazard. The most common claim is that a house fire combined with non-certified equipment installed would result in an insurance company refusing to pay.

Rather than just repeat this surely sage advice from the Internet, I asked my insurance agent about uncertified equipment in the case of a fire. I discovered that insurance agencies avoid giving definite answers about claim payments. The response that came back was “it depends”: homeowner’s insurance covers events that are accidental and sudden. If a homeowner was aware that they were using uncertified equipment, then it could be categorized as “not an accident”. So far, the myth seems plausible. The final answer from the insurance agency: it’s possible that a non UL-certified device could result in denial of payment on a claim, but it depends on the policy and other details– why take the risk? Certification marks make insurance companies happier.

I also talked to my city’s electrical inspector about the issue. He commented that non-certified equipment is a violation of electrical code when it is hard-wired into a house. He echoed the warning that an insurance company could refuse to pay, but added that in the case of injury, there could be even further liability issues. I’ve opted to use certified equipment in my house. You’ll have to make your own decision about what equipment you’re willing to use.

There are some devices on Amazon that claim to have certification, but searching the certification database leads me to believe that not all of those claims are valid. If in doubt, there is a searchable UL database, as well as a searchable Intertek database.
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KiCad And FreeCAD Hack Chat

April 22, 2019 by 4 Comments

Join us Wednesday at noon Pacific time for the KiCad and FreeCAD Hack Chat led by Anool Mahidharia!

The inaugural KiCon conference is kicking off this Friday in Chicago, and KiCad aficionados from all over the world are gathering to discuss anything and everything about the cross-platform, open-source electronic design automation platform. As you’d expect, Hackaday will have a presence at the conference, including a meet and greet after party. There’ll also be talks by a couple of our writers, including Anool Mahidharia, who’ll be taking time out of his trip to the States to drop by the Hack Chat with a preview of his talk, entitled “Fast 3D Model Creation with FreeCAD”.

Join us for the KiCad and FreeCAD Hack Chat this week with your questions about KiCad and FreeCAD. If you’ve got some expertise with electronic design tools, make sure you come by and contribute to the discussion too — we’d love to hear your insights. And as always, you can get your questions queued up by leaving a comment on the KiCad and FreeCAD Hack Chat event page and we’ll put them on the list for the Hack Chat discussion.

join-hack-chatOur Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, April 24, at noon, Pacific time. If time zones have got you down, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.

Why Satellites Of The Future Will Be Built To Burn

April 22, 2019 by 33 Comments

There’s no shortage of ways a satellite in low Earth orbit can fail during the course of its mission. Even in the best case scenario, the craft needs to survive bombardment by cosmic rays and tremendous temperature variations. To have even a chance of surviving the worst, such as a hardware fault or collision with a rogue piece of space garbage, it needs to be designed with robust redundancies which can keep everything running in the face of systemic damage. Of course, before any of that can even happen it will need to survive the wild ride to space; so add high-G loads and intense vibrations to the list of things which can kill your expensive bird.

After all the meticulous engineering and expense involved in putting a satellite into orbit, you might think it would get a hero’s welcome at the end of its mission. But in fact, it’s quite the opposite. The great irony is that after all the time and effort it takes to develop a spacecraft capable of surviving the rigors of spaceflight, in the end, its operators will more than likely command the craft to destroy itself by dipping its orbit down into the Earth’s atmosphere. The final act of a properly designed satellite will likely be to commit itself to the same fiery fate it had spent years or even decades avoiding.

You might be wondering how engineers design a spacecraft that is simultaneously robust enough to survive years in the space environment while at the same time remaining just fragile enough that it completely burns up during reentry. Up until fairly recently, the simple answer is that it wasn’t really something that was taken into account. But with falling launch prices promising to make space a lot busier in the next few years, the race is on to develop new technologies which will help make sure that a satellite is only intact for as long as it needs to be.

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Video Mangler For All Your Video Mangling Needs

April 22, 2019 by 8 Comments

Back in the ’70s and ’80s, before we had computers that could do this sort of thing, there were fully analog video effects. These effects could posterize or invert the colors of a video signal, but for the best example of what these machines could do just go find some old music videos from Top of The Pops or Beat Club. Stuff gets weird, man. Unfortunately, all those analog broadcasting studios ended up in storage a few years ago, so if you want some sweet analog effects, you’re going to have to build your own. That’s exactly what [Julien]’s Video Mangler does. It rips up NTSC and PAL signals, does some weird crazy effects, and spits it right back out.

The inspiration for this build comes from an old ’80s magazine project called the ‘video palette’ that had a few circuits that blurred the image, turned everything negative, and could, if you were clever enough, become the basis for a chroma key. You can have a lot of fun when you split a video signal into its component parts, but for more lo-finess [Julien] is adding a microcontroller and a 12-bit DAC to generate signals that can be mixed in with the video signals. Yes, all of this can still be made now, even though analog TV died a decade ago.

The current status of this project is a big ‘ol board with lots of obscure chips, and as with everything that can be described as circuit bending, there’s going to be a big panel with lots of dials and switches, probably stuffed into a laser-cut enclosure. There’s a mic input for blurring the TV with audio, and enough video effects to make any grizzled broadcast engineer happy.

RIP Rex Garrod, Creator Extraordinaire

April 22, 2019 by 30 Comments

Earlier this month, the youth motocross champion, special effects creator, inventor, TV presenter, and Robot Wars competitor, [Rex Garrod] died at the age of 75 after a long battle with dementia. We do not often carry obituaries here at Hackaday, and it’s possible that if you are not a Brit you may not have heard of [Rex], but his work in the time before YouTube would have made him an international must-watch star had he been operating in the age of on-demand Internet video.

I first became aware of Rex when he appeared as assistant to [Tim Hunkin] on his Secret Life of Machines TV series in the late 1980s. He was the man whose job we all wanted, making the most incredible machines and operating them for our entertainment. Our Hardware heroes tribute to [Tim] has a picture of him operating the needle on a giant mock-up of a sewing machine, but he appeared in many more episodes. Of the many tributes to [Rex] that have appeared over the last few days it is [Tim]’s one that probably says the most about his appeal to our community. His propensity for picking up interesting parts from junkyards strikes a chord, and the tale of hugely overpowering car wiper motors by allowing them to be submerged in water is pure genius.

To a slightly younger generation he is best known for his appearances in the British Robot Wars series‘ with his Cassius series of fighting robots. He created one of the first really potent flipper robots in UK robotic combat, and incidentally the first effective self-righting mechanism. As one of the many members of the SMIDSY team that didn’t appear on the recorded TV series’ I encountered him only peripherally, but I remember his work being a major influence on SMIDSY’s run-any-way-up design. Meanwhile for a younger generation still he created the models for the popular children’s TV character Brum, an anthropomorphised scale-model Austin 7 car.

We’ll leave you with a couple of videos featuring [Rex]. The first is from The Secret Life of Machines, in which along with [Tim] he helps explain electronics from first principles, while the second is a fan-created medley of his Robot Wars appearances. Rest in peace [Rex], and thank you.

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A High-Speed Slide Scanner Build

April 21, 2019 by 19 Comments

Photographic slides were popular in the middle part of the 20th century, but are long forgotten now. If you’ve found a handful in a dusty attic, you might consider sending them away to be digitized professionally, or using a flatbed scanner at home. [Bryan Howard] found himself with over 200,000 slides, however, so that just wouldn’t do. Instead, he endeavored to build an automated scanner of his own. 

Like many similar projects, [Bryan] started with an existing slide projector as a base. This means that all the difficult work of slide transport is already taken care of. The projector has then been upgraded with an LED light source and other tweaks befitting its new role. An Arduino Pro Micro runs the show, firing off the camera to image each slide before loading the next one into place. The DSLR responsible for imaging is then hooked up to a PC so the incoming images can be checked while the machine is in operation.

Preliminary tests are promising, with the scanner successfully capturing several slides in a row. [Bryan] estimates that, with a capture time of between 1 and 2 seconds per slide, it should take somewhere between 2-5 days to image the entire collection.

We wish [Bryan] the best of luck with the project, and look forward to seeing the final results. We’ve seen similar work before, too. Video after the break.

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Build Your Own Freezer With Thermoelectric Coolers

April 21, 2019 by 40 Comments

Freezers are highly useful devices. You can preserve food, stop a dead animal from stinking out your apartment, and keep your vodka at the optimal drinking temperature. Of course, most of us bought ours from the local whitegoods store, but [Tech Ingredients] set out to build his own (YouTube, embedded below).

Unlike your freezer at home, this build doesn’t use the typical heat pump and refrigeration cycle with a compressor and expansion valve and so on. Instead, this freezer uses thermoelectric devices to pump heat, in combination with a glycol cooling circuit and fan-cooled radiators.

It’s not the most efficient or practical way to build a freezer, but it is functional and the device demonstrably works, making ice cubes over the course of a few hours. Performance can be further improved by moving the radiator assembly outdoors to make the most of the low ambient temperatures.

[Tech Ingredients] has further plans to experiment with a dessicant-based refrigeration system, and reports that initial results are promising. We’re eager to see how that goes; we’re fans of any rig that can cool a beer down in no time flat. Video after the break.

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