The Engineering Case for Fusing Your LED Strips

Modern LED strips are magical things. The WS2812 has allowed the quick and easy creation of addressable RGB installations, revolutionizing the science of cool glowy things. However, this accessibility means that it’s easy to get in over your head and make some simple mistakes that could end catastrophically. [Thomas] is here to help, outlining a common mistake made when building with LED strips that is really rather dangerous.

The problem is the combination of hardware typically used to run these LED strings. They’re quite bright and draw significant amounts of power, each pixel drawing up to 60 mA at full-white. In a string of just 10 pixels, the strip is already drawing 600 mA. For this reason, it’s common for people to choose quite hefty power supplies that can readily deliver several amps to run these installations.

It’s here that the problem starts. Typically, wires used to hook up the LED strips are quite thin and the flex strips themselves have a significant resistance, too. This means it’s possible to short circuit an LED strip without actually tripping the overcurrent protection on something like an ATX power supply, which may be fused at well over 10 amps. With the resistance of the wires and strip acting as a current limiter, the strip can overheat to the point of catching fire while the power supply happily continues to pump in the juice. In a home workshop under careful supervision, this may be a manageable risk. In an unattended installation, things could be far worse.

Thankfully, the solution is simple. By installing an appropriately rated fuse for the number of LEDs in the circuit, the installation becomes safer, as the fuse will burn out under a short circuit condition even if the power supply is happy to supply the current. With the example of 10 LEDs drawing 600 mA, a 1 amp fuse would do just fine to protect the circuit in the event of an accidental short.

It’s a great explanation of a common yet dangerous problem, and [Thomas] backs it up by using a thermal camera to illustrate just how hot things can get in mere seconds. Armed with this knowledge, you can now safely play with LEDs instead of fire. But now that you’re feeling confident, why not check out these eyeball-searing 3 watt addressable LEDs?

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3D Print Yourself A Flame Thrower

For a large proportion of the world’s population, it’s now winter, which means there’s plenty of rain and snow to go around. With the surrounding environment generally cooler and wetter than usual, it’s a great time to experiment with dangerous flame based projects, like this wrist mounted flame thrower.

It’s a build that does things in both a simple and complicated way, all at once. Fuel is provided by a butane canister with a nozzle that needs to be pressed to release the gas.  A servo is used to push the canister into a 3D printed housing, releasing the gas into a pipe to guide the fuel towards the end of the user’s wrist. The fuel is then ignited by a heated coil of wire. The heated wire and the servo are both controlled by standard radio control gear typically seen on RC cars or buggies. Using the brushed speed controller to run the heated coil is particularly off-beat, but it does the job admirably.

Overall, it goes without saying that this build presents some serious risks of burns and other injuries. However, the fundamental premise is sound, and it does what it says on the tin with parts that could be readily found in the average junk box.

For another take on a wrist-mounted flame thrower, check out this version using a scavenged solenoid valve.

Mike Ossmann and Dominic Spill: IR, Pirates!

Mike Ossmann and Dominic Spill have been at the forefront of the recent wave of software-defined radio (SDR) hacking. Mike is the hardware guy, and his radio designs helped bring Bluetooth and ISM-band to the masses. Dominic is the software guy who makes sure that all this gear is actually usable. The HackRF SDR is still one of the best cheap choices if you need an SDR that can transmit and receive.

So what are these two doing on stage giving a talk about IR communication? Can you really turn traffic lights green by blinking lights? And can you spoof a TV remote with a cardboard cutout, a bicycle wheel, and a sparkler? What does IR have to do with pirates, and why are these two dressed up as buccaneers? Watch our video interview and find out, or watch the full talk for all of the juicy details.

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This Power Strip is a Fire Starter

A few weeks ago I needed a power strip in my home office. The outlet in question is located behind a filing cabinet so it would need a low profile plug. I jumped on Amazon to buy a surge suppressor strip. That’s when I noticed strips with rotating plugs. I’ve always had some apprehensions about plugs like that, though I could never quite put my finger on why. Looking at the reviews on this particular plug, I found some scary issues. Photos of melted plugs, melted outlets, and cries of “fire hazard”. So I did what any crazy hacker would do – bought two power strips. One with a fixed right angle plug to use in my office, and one with a rotating plug to tear down.

Failed plug – from Amazon reviews

Surge suppressors, power strips, outlet strips, they have many names. Underwriter’s Laboratories (UL) calls them “Relocatable power taps”. They all have several outlets, most have a circuit breaker of some sort inside, and some have circuits for surge suppression. These are some of the most common devices to find in the modern home. Many of our houses were designed and built before surround sound, cable boxes, computers, modems, cell phone chargers, tablet chargers, and all our other modern conveniences. There weren’t as many electrical loads, so the houses didn’t have many outlets. Power strips solve this problem.

After a couple of days, I had my strips in hand. I expected the plug to rotate once – maybe 270 degrees. That would indicate there were wires connecting the rotating head to rest of the plug. Not so – this plug would spin round and round all day long.

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Sector67 Hackerspace Rocked by Explosion at New Location

Madison, WI hackerspace Sector67 is in a period of transition as they move from their current rented location to a new property that will be their permanent home a half mile away. Last Wednesday (September 20, 2017) an unfortunate propane explosion in the new building led to the injury of Chris Meyer, the founder and director of the hackerspace.

The structure has been stabilized and renovation is continuing, but Chris was seriously burned and will be in the hospital for at least a month with a much longer road to complete recovery. It is fortunate that nobody else was injured.

This accident comes at a time when Sector67 essentially has two spaces to maintain; the existing space is still running, but many of the members are focused on the construction of the new space. The building needs significant work before the move can take place. Currently the roof is being raised so that the building can go from one awkward-height story to two normal stories, doubling the size. An expiring lease and imminent demolition of the current location by developers means the clock is still ticking on the move, and this explosion means Sector67 will have to work even harder, and without the presence and constant effort of the person who has been leading the project.

A GoFundMe campaign for Sector67 has been started and is well on its way towards helping Chris and Sector67.

Hackaday Prize Entry: The Weedinator Project, Now with Flame

We like that the Weedinator Project is thinking big for this year’s Hackaday Prize! This ambitious project by [TegwynTwmffat] is building on a previous effort, which was a tractor mounted weeding machine (shown above). It mercilessly shredded any weeds; the way it did this was by tilling everything that existed between orderly rows of growing leeks. The system worked, but it really wasn’t accurate enough. We suspect it had a nasty habit of mercilessly shredding the occasional leek. The new version takes a different approach.

The new Weedinator will be an autonomous robotic rover using a combination of GPS and colored markers for navigation. With an interesting looking adjustable suspension system to help with fine positioning, the Weedinator will use various attachments to help with plant care. Individual weeds will be identified optically and sent to the big greenhouse in the sky via precise flame from a small butane torch. It’s an ambitious project, but [TegwynTwmffat] is building off experience gained from the previous incarnation and we’re excited to see where it goes.

North Carolina Hackerspace Destroyed by Fire, Members Vow to Rebuild

There’s something about old industrial buildings that just seems to attract hackerspaces. It could be the open floor plans typical in buildings that used to house big manufacturing operations, or it could be a desire to reinvigorate places where machines once hummed and skilled hands plied their trades. Whatever the attraction, the relationship is not without risk; old buildings with wood floors and frames can be tinderboxes, and tragedy can strike at any moment.

Such a fate befell The Foothills Community Workshop in Granite Falls, North Carolina, this past Friday. Details are still sketchy as the remnants of the 75,000-square foot former Shuford Mills textile factory are still smoldering, and the Fire Marshal’s investigation is not yet complete. Thankfully, no lives were lost, and injuries were limited to heat exhaustion of several of the firefighters from 16 counties who battled the blaze in the hot and humid North Carolina Piedmont.

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