How To Design Your Own LED Driver

August 14, 2012 by Mike Szczys 8 Comments

If you find yourself in need of a driver for a high power string of LEDs this is a must read. [Limpkin] just designed this driver as a contract job. He can’t show us the schematic, but he did share some tips on how to build an LED driver around a MAX16834 chip.

As you move to higher power designs the barriers to success pile up rather quickly. Using a chip like the MAX16834 really helps to simplify the task as it can be used as a boost or buck converter, it includes functionality that allows for dimming, and it’s a constant currents solution. There are board design issues that need to be accounted for in these designs. [Limkin] included links to a few calculators that will help you determine trace width based power levels used with the driver. He also recommends using copper pours on both sides of the board connected with vias to help dissipate heat. To that end he used an IR thermometer for feedback during testing.

It’s too bad he doesn’t have any photos of the device at work. If you build something similar please take some pictures and tip us off about it.

Building A Casting Furnace With Heat Exchanger

August 13, 2012 by Mike Szczys 7 Comments

This completely DIY casting furnace turned out just great thanks to all the work [Biolit11] put into it along the way. He wanted to replace his older furnace with one that was more efficient, and to that end he built a heat exchanger into the design. This way the exhaust will preheat the intake air.

The furnace itself started with the shell of an old electric water heater. Excluding the design process, the majority of the build involved mold making. For circular parts he’s using quick tube, the paperboard forms used for pouring concrete footings. For more intricate parts he shaped polystyrene. They are layered in place and high-temperature cement is poured to form the permanent parts. After it hardens the polystyrene can be removed in chunks.

The heat exchanger is the part to the left. It includes several wide, flat pipes made of cement for removing the exhaust. Around those pipes a snaking metal chase carries the intake air which picks up the heat as it passes over the exhaust pipes.

For his first run with the new furnace he melted down a bunch of scrap aluminum and poured ingots.

[Thanks DC3]

Building A Coal Forge

August 11, 2012 by Mike Szczys 21 Comments

We don’t get to see Blacksmith hacks around here too often. But even if they were rolling in on a weekly basis we think this one would be considered the special expanded edition with full-color centerfold. The sixty-five images in this coal forge build log are all commented and just begging to steal your attention for part of the afternoon.

The build mostly involves fabricating a system for injecting air into the forge and providing a mechanism for evacuating the waste ash. [BillDaCat] starts with a 3″ pipe as the ash dump, adding a latching door used to empty it when full. He then welds together a metal trough with a slotted bottom to hold the fiery fury, attaching the ash dump below. He uses a plasma cutter to add an opening in the upper portion of the ash dump for a blast gate.

If you’re excited about his build you should also check out the metal pour and the induction furnace.

[via Reddit]

How Not To Dim EL Panels, TRIACs!

August 10, 2012 by Jesse Congdon 15 Comments

We’ve all been there: an exciting brilliant idea, scratched onto a napkin, hastily plugged into a breadboard, all for naught. Even the best ideas sometimes suffer from a heavy dose of reality. [Ch00f] over at ch00ftech recently had a similar experience dimming an EL panel of his using a TRIAC and some clever waveform manipulation. Instead of tossing the parts ~~across the room in a fit~~ aside and moving on he goes into a detailed analysis of what went wrong.

This method differs from the way most EL drivers dim output loads, instead of chopping the output like a PWM controlled LED the TRIAC snips the ends of the waveform and makes an ugly but less powerful output. The issue with this method is that when you cut the waveform during non-zero crossings it causes massive current spikes. These can wreak havoc on a cheap EL inverter and generally cause headaches all around. [Ch00f ] speculates that his woes may be due to the fact that EL wire is a capacitive load, causing voltage to fall out of phase with the current. This is one of those engineering problems with a thousand and one answers, we can’t wait to see what he comes up with.

Check out the writeup for all the “deets” (as [ch00f] would say) as it is a pretty good primer on TRIAC operation. If there isn’t enough glowy wire in this post you can also check out this sound reactive panel or an informative guide on EL or even more from [ch00f] in general.

Fuse Making Machine

August 10, 2012 by Mike Szczys 19 Comments

This is a fuse making machine that operates nearly as well as a factory machine would. Have you figured out what exactly this is yet? It’s not an electrical fuse, it’s a Visco Fuse. Still not totally clear? Don’t worry, we had to look it up too. Visco Fuse is a high-quality safety fuse used in fireworks.

[Robert McMullen] built the machine as part of his degree in Mechanical Engineering at Olin College. But there’s a hobby twist behind its genesis. When he has free time he participates in Olin’s Fire Arts Club and we’re sure this stuff comes in handy. The fuse is made by encapsulating a stream of gunpowder in a tube of woven thread. Twenty spools of thread wrap their way around the nozzle of a fine funnel. Once the casing is in place the machine coats it in a waterproof lacquer.

The image above only shows the base of the machine. All the fun parts (and test burns including one underwater) can be seen in the video after the break. Continue reading “Fuse Making Machine” →

Edison’s Cradle Is A Bright Idea

August 6, 2012 by Caleb Kraft 45 Comments

This interesting take on Newton’s Cradle is called “Asobi” and was created by [Yasutoki Kariya]. However, [Johnny] at Spoon and Tamago dubbed it “Edison’s Cradle”, which we think is a great name.

As you can make out in the video, it isn’t really a Newton’s Cradle. There is a solenoid pushing the bulbs at the end out at the correct time, but that’s fine. The overall result is quite brilliant. Unfortunately, we don’t know much about the setup. Anyone have more information? Anyone want to take a stab at making “Tesla’s cradle”?

[via Make]

Continue reading “Edison’s Cradle Is A Bright Idea” →

Control Giant Fireballs With Your Mind

August 6, 2012 by Eric Evenchick 9 Comments

[Matt Oehrlein] and [Ed Platt] from the i3 Detroit hackerspace created the Mind Flame project. The project uses Electroencephalography (EEG) sensors from NeuroSky to measure the user’s concentration level. When you’re concentrating hard enough, the Mind Flame launches a giant fireball, which probably breaks your concentration pretty quickly.

Propane is accumulated in tanks, and then released past a hot surface carbide igniter. It looks like an Arduino is used to open the valve, and the result is a massive fireball controlled by your brainwaves.

The Mind Flame was demoed at the Detroit Maker Faire as a competition. Two participants face off to see who can concentrate the hardest and make the device launch three fireballs first. In the future, they want to incorporate new competitive elements. One example is placing wooden houses in the line of fire, and letting opponents try to burn down their adversary’s house before their’s is set ablaze.

You can check out an interview about the project here.

[Via Make]