World’s Largest Telescope Stopped By LED

October 3, 2017 by Michael Uttmark 75 Comments

Earlier this year a simple indicator LED brought the Keck 1 telescope, a 370 tons mass, to a halting stop. How exactly did an LED do this? Simple: it did nothing.

As it so happens, [Andrew Cooper] was just about the leave the summit of Mauna Kea (in Hawaii) when his radio instructed him otherwise: there was an issue. Upon returning, [Andrew] was met by a room of scientists and summit supervisors. “Yeah, this was not good, why are they all looking at me? Oh, h%#*!” The rotor wasn’t moving the telescope, and “no rotator equals no science data.” After being briefed on the problem, [Andrew] got to work. Was it a mechanical issue? No: manual mode worked quite fine, also indicating that the amplifiers and limit switches are functional as well.

Jumping from chip to chip, [Andrew] came across an odd voltage: 9.36V. In the CMOS [Andrew] was investigating, this voltage should have High (15V) or Low (0v) and nowhere in between. Judging by the 9.36V [Andrew] decided to replace the driving IC. One DS3632 later, nothing had changed. Well, maybe is one of the loads pulling the line low? With only two choices, [Andrew] eliminated that possibility quickly. Likely feeling as if he was running out of proverbial rope, [Andrew] remembered something important: “the DS3236 driving this circuit is an open collector output, it needs a pull-up to go high.”

Reviewing the schematic, [Andrew] identified the DS3236’s pull-up: an LED and its current limiting resistor. While the carbon composition resistor was “armageddon proof,” [Andrew] was suspicious of the LED. “Nick, can you get me a 5k resistor from the lab?” Hold the resistor on the pins of the chip and the amplifiers immediately enabled.

[Andrew] summarizes things quite well: “yes… One of the world’s largest telescopes, 370 tons of steel and glass, was brought to a halt because of a bad indicator LED”. It stopped things by doing nothing, or rather, by not turning on.

We love it when we get troubleshooting stories, and if you share our interest in problem-solving, check out this broken power supply troubleshooting or learn what could go wrong with I2C.

Edit: Keck 1 is one of the largest optical telescopes in the world. Thanks to [Josh] for noticing our error.

FM Snake Feeds Off Radio Waves

October 2, 2017 by John Baichtal 54 Comments

[Eric Brasseur] built a radio-detecting snake that consists of a LED that lights up when around reasonably strong radio waves. Near an FM radio mast you’ll find a huge amount of waste energy being dumped out in the 88 to 108 MHz range.

[Eric]’s rig consists of a pair of 1N6263 Schottky diodes, flip-flopped with one set of ends soldered to the antenna and the other ends soldered to the leads of the LED with about a foot of wire in between. The antenna can be a single wire as the diodes are soldered together. This one is around 4 feet in length for a total length of around 160 cm or a little over 5 feet. He went with a red LED just to give it a greater chance of being seen when illuminated by a distant or weak source of radio waves.

Hackaday loves its radio hacks; check out our posts on improving WiFi throughput with FM radio and building a modern DIY FM radio.

[Thanks, Alain!]

Friday Hack Chat: All About LED Design

September 27, 2017 by Brian Benchoff 13 Comments

There are three great enabling technologies of the last twenty years. The first is lithium batteries that hold a lot of juice. Quadcopters wouldn’t exist without them, and the Tesla Model S wouldn’t either. The second is crazy powerful brushless motors. Here, again, quads wouldn’t exist without them, but we’re also getting smaller, torquier, and more powerful motion platforms.

The third great enabling technology in recent memory is LEDs. Remember when the PlayStation 2 came out, and everyone was amazed by the blue LED? That blue LED won a Nobel Prize. Now, we have LED light bulbs, LEDs in any color of the rainbow, powerful UV LEDs, and bazillion candela flashlights. LEDs are awesome.

For this week’s Hack Chat, we’re going to be talking all about LEDs. Everything from strips to rings, discrete to waterproof, COBs, weird colors, and everything in between. If you’re looking to replace your workshop lighting with LEDs, this is the Hack Chat for you. If you’ve ever wondered about the quality of LEDs, and the price-performance ratio, this is for you. This is all about blinky bling.

Our guest for this week’s Hack Chat will be [Metalnat], founder of the Burbank MakerSpace, a recent resident of the Supplyframe DesignLab where he designed a VR controller, and worked on Crane, a flapping automaton that glided over the playa at this year’s Burning Man. During this Hack Chat, we’ll be talking about LEDs, including installation methods, types of LEDs, suppliers, and LED manufacturing methods.

This is a Hack Chat, so we’re taking questions from the audience. Here’s a spreadsheet we’ll be using to guide the discussion.

Here’s How To Take Part:

Our Hack Chats are live community events on the Hackaday.io Hack Chat group messaging. This Hack Chat will be going down noon, Pacific time on Friday, September 29th. Sidereal and solar getting you down? Wondering when noon is this month? Not a problem: here’s a handy countdown timer!

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 Friday; join whenever you want and you can see what the community is talking about.

Need A Night-Light?

September 19, 2017 by Lauren Faris 36 Comments

[Scott] created an LED candle in preparation for the big mac daddy storm (storms?) coming through. Like millions of other people in Florida, he was stuck at home with his roommates when an oncoming hurricane headed their way. Worrying about blundering about in the dark when the power inevitably went out, they set off to gather up all of the candles they had lying around. Realizing the monstrous pile of candles and matches looked more and more like a death wish, the decision was made to create a makeshift light out of what components they had on hand. Now, not having access to any outside sources for parts means that you are going to have a bare bones model.

That being said, this straightforward light only takes a couple of seconds to put together. Jury rig a couple of AA or AAA batteries up, then slap on a resistor, LED, and jumper to get that sucker running. Wrap electrical tape around the whole thing, or even try duct tape, whatever gets the job done. A little paper hat on top of it will diffuse the light and bada bing, bada boom, you’re all done. Generally though, soldering directly onto a battery is not a wise idea. So, if you want to get fancy, perhaps a better alternative is to have a battery casing as shown below.

This LED candle is a clear option if your home isn’t a micro warehouse for electronic components (apparently it is frowned upon to clog up your garage for projects), and you have limited time. However, if you have a number of extra minutes lying around before your windows blow in, see if you can top the brightest flashlight ever made (thus far). Continue reading “Need A Night-Light?” →

Super Simple Controller For Motorcycle LED Lights

September 9, 2017 by Anool Mahidharia 32 Comments

For automobiles, especially motorcycles, auxiliary lighting that augments the headlights can be quite useful, particularly when you need to drive/ride through foggy conditions and poorly lit or unlit roads and dirt tracks. Most primary lighting on vehicles still relies on tungsten filament lamps which have very poor efficiency. The availability of cheap, high-efficiency LED modules helps add additional lighting to the vehicle without adding a lot of burden on the electrical supply. If you want to add brightness control, you need to either buy a dimmer module, or roll your own. [PatH] from WhiskeyTangoHotel choose the latter route, and built a super simple LED controller for his KLR650 bike.

He chose a commonly available 18 W light bar module containing six 3 W LEDs. He then decided to build a microcontroller based dimmer to offer 33%, 50% and 100% intensities. And since more code wasn’t going to cost him anything extra, he added breathing and strobe modes. The hardware is as barebones as possible, consisting of an Arduino Nano, linear regulator, power MOSFET and control switch, with a few discretes thrown in. The handlebar mounted control switch is a generic motorcycle accessory that has two push buttons (horn, headlight) and a slide switch (turn indicators). One cycles through the various brightness modes on the pushbutton, while the slide switch activates the Strobe function. A status indicator LED is wired up to the Nano and installed on the handlebar control switch. It provides coded flashes to indicate the selected mode.

It’s a pity that the “breathing” effect is covered under a patent, at least for the next couple of years, so be careful if you plan to use that mode while on the road. And the Strobe mode — please don’t use it — like, Ever. It’s possible to induce a seizure which won’t be nice for everyone involved. Unless you are in a dire emergency and need to attract someone’s attention for help.

Continue reading “Super Simple Controller For Motorcycle LED Lights” →

1.5 Million Dollars Buys 850,000 LEDs And 29 Raspberry Pis

September 7, 2017 by Elliot Williams 83 Comments

You think you like RGB LEDs? Columbus, OH art professor [Matthew Mohr] has more blinkenlove than you! His ~~airport~~– convention-center-scale installation piece is an incredible 850,000 RGB LEDs wrapped around a 14-foot tall face-shaped sculpture that projection-maps participants’ faces onto the display. To capture images, there is also a purpose-built room with even illumination and a slew of Raspberry Pi cameras to take pictures of the person’s face from many angles simultaneously.

Besides looking pretty snazzy, the scale of this is just crazy. For instance, if you figure that the usual strip of 60 WS2812s can draw just about 9.6 watts full on, that scales up to 136 kW(!) for the big head. And getting the control signals right? Forgeddaboutit. Prof. [Mohr], if you’re out there, leave us some details in the comments.

(Edit: He did! And his website is back up after being DOSed. And they’re custom LEDs that are even brighter to compete with daylight in the space.)

What is it with airports and iconic LED art pieces? Does anyone really plan their stopovers to see public art? How many of you will fly through Columbus on purpose now?

Coin-Sized LED Control

September 5, 2017 by John Baichtal 10 Comments

EE and firmware developer [Enrico] had played with LEDs as a kid, burning out his fair share of them by applying too much current. With the benefit of his firmware chops, he set about creating a board that drives LEDs properly.

[Enrico]’s project centers around a Texas Instruments LM3405 buck controller. It accepts input voltage from anywhere from 3V to 20V and outputs up to 20V/15W to one or more LEDs. He built a ton of safety features into it like short-circuit and open-circuit immunity, temperature control, and auto-off switching when idle. He also created a LED board to test the maximum efficiency of the driver. It consists of four Luxeon Rebel ES diodes, one each RGB and W. The entire back of the LED board is copper, with a monster heat sink attached.

You can follow along with the Glighter-S project on Hackaday.io, or you can buy one of his boards from his Tindie store.

We’ve covered LED drivers extensively in the past, with posts on a simple 10-watt LED driver and how to design your own LED driver.