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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Modder puts Computer inside a Power Supply

When building a custom computer rig, most people put the SMPS power supply inside the computer case. [James] a.k.a [Aibohphobia] a.k.a [fearofpalindromes] turned it inside out, and built the STX160.0 – a full-fledged gaming computer stuffed inside a ATX power supply enclosure. While Small Form Factor (SFF) computers are nothing new, his build packs a powerful punch in a small enclosure and is a great example of computer modding, hacker ingenuity and engineering. The finished computer uses a Mini-ITX form factor motherboard with Intel i5 6500T quad-core 2.2GHz processor, EVGA GTX 1060 SC graphics card, 16GB DDR4 RAM, 250GB SSD, WiFi card and two USB ports — all powered from a 160 W AC-DC converter. Its external dimensions are the same as an ATX-EPS power supply at 150 L x 86 H x 230 D mm. The STX160.0 is mains utility powered and not from an external brick, which [James] feels would have been cheating.

For those who would like a quick, TL;DR pictorial review, head over to his photo album on Imgur first, to feast on pictures of the completed computer and its innards. But the Devil is in the details, so check out the forum thread for a ton of interesting build information, component sources, tricks and trivia. For example, to connect the graphics card to the motherboard, he used a “M.2 to powered PCIe x4 adapter” coupled with a flexible cable extender from a quaint company called Adex Electronics who still prefer to do business the old-fashioned way and whose website might remind you of the days when Netscape Navigator was the dominant browser.

As a benchmark, [James] posts that “with the cover panel on, at full load (Prime95 Blend @ 2 threads and FurMark 1080p 4x AA) the CPU is around 65°C with the CPU fan going at 1700RPM, and the GPU is at 64°C at 48% fan speed.” Fairly impressive for what could be passed off at first glance as a power supply.

The two really interesting take away’s for us in this project are his meticulous research to find specific parts that met his requirements from among the vast number of available choices. The second is his extremely detailed notes on designing the custom enclosure for this project and make it DFM (design for manufacturing) friendly so it could be mass-produced – just take a look at his “Table of Contents” for a taste of the amount of ground he is covering. If you are interested in custom builds and computer modding, there is a huge amount of useful information embedded in there for you.

Thanks to [Arsenio Dev‏] who posted a link to this hilarious thread on Reddit discussing the STX160.0. Check out a full teardown and review of the STX160.0 by [Not for Concentrate] in the video after the break.

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Not Quite 101 Uses For An ATX Power Supply

The PC power supply has been a standard of the junk box for the last couple of decades, and will probably continue to be for the foreseeable future. A product that is often built to a very high standard and which will give years of faithful service, yet which has a life of only a few years as the PC of which it is a part becomes obsolete. Over the decades it has evolved from the original PC and AT into ATX, supplying an ever-expanding range of voltage rails at increasing power levels. There have been multiple different revisions of the ATX power supply standard over the years, but they all share the same basic form factor.

So a pile of ATX supplies will probably feature in the lives of quite a few readers. Most of them will probably be old and obsolete versions of little use with today’s motherboards, so there they sit. Not small enough to ignore, yet Too Good To Throw Away. We’re going to take a look at them, try to work out what useful parts they contain, and see a few projects using them. Maybe this will provide some inspiration if you’re one of those readers with a pile of them seeking a purpose.

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Not Your Typical ATX Power Supply Hack

Power supplies are essential for at home tinkering and electronics hacking. Unfortunately, they’re really quite expensive, and a bit out of reach for most hobbyists. Computer ATX power supplies are a cheap alternative, although they usually tend to lack the features of real bench power supplies… unless you hack yours like [Mark Schoonover]!

When [Mark] set out on this project he wanted to use as many recycled components as possible, but still come up with an extremely functional bench top power supply. He snagged a 500W ATX power supply from one of his kid’s old desktop PC’s, grabbed some old wall-warts for individual current limited supplies (apparently ATX PSU’s don’t have 5V rails anymore?), and put it all into a nice big project box.

He’s even thrown in a voltage regulator with current metering and a nice set of 7-segment displays!

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