Author: Dan Maloney

3373 Articles

Chest Of Drawers Stores Audio Memories

September 18, 2017 by 15 Comments

Some people collect stamps, some collect barbed wire, and some people even collect little bits of silicon and plastic. But the charmingly named [videoschmideo] collects memories, mostly of his travels around the world with his wife. Trinkets and treasures are easy to keep track of, but he found that storing the audio clips he collects a bit more challenging. Until he built this audio memory chest, that is.

Granted, you might not be a collector of something as intangible as audio files, and even if you are, it seems like Google Drive or Dropbox might be the more sensible place to store them. But the sensible way isn’t always the best way, and we really like this idea. Starting with what looks like an old card catalog file — hands up if you’ve ever greedily eyed a defunct card catalog in a library and wondered if it would fit in your shop for parts storage — [videoschmideo] outfitted 16 drawers with sensors to detect when they’re opened. Two of the drawers were replaced by speaker grilles, and an SD card stores all the audio files. When a drawer is opened, a random clip from that memory is played while you look through the seashells, postcards, and what-have-yous. Extra points for using an old-school typewriter for the drawer labels, and for using old card catalog cards for the playlists.

This is a simple idea, but a powerful one, and we really like the execution here. This one manages to simultaneously put us in the mood for some world travel and a trip to a real library.

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Take A Time-Lapse Or Bake A Cake With This Kitchen Timer Panning Rig

September 17, 2017 by 22 Comments

Seems like the first thing the new GoPro owner wants to do is a time-lapse sequence. And with good reason – time-lapses are cool. But they can be a bit bland without a little camera motion, like that provided by a dirt-cheap all-mechanical panning rig.

Let’s hope [JackmanWorks]’ time-lapse shots are under an hour, since he based his build on a simple wind-up kitchen timer, the likes of which can be had for a buck or two at just about any store. The timer’s guts were liberated from the case and a simple wooden disc base with a 1/4″-20 threaded insert for a tripod screw was added. The knob, wisely left intact so the amount of time left in the shot is evident, has a matching bolt for the camera’s tripod socket. Set up the shot, wind up the timer, and let it rip at 1/60 of an RPM. Some sample time-lapse shots are in the video below.

Turning this into a super-simple powered slider for dollying during a time-lapse wouldn’t be too tough — if you’ve already got a nice pantograph slide rig built.

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A Battery-Tab Welder With Real Control Issues

September 16, 2017 by 56 Comments

Spot welding should easier than it looks. After all, it’s just a lot of current in a short time through a small space. But it’s the control that can make the difference between consistently high-quality welds and poor performance, or maybe even a fire.

Control is where [WeAreTheWatt]’s next-level battery tab spot welder shines. The fact that there’s not a microwave oven transformer to be seen is a benefit to anyone sheepish about the usual mains-powered spot welders we usually see, even those designed with safety in mind. [WeAreTheWatt] chose to power his spot welder from a high-capacity RC battery pack, but we’d bet just about any high-current source would do. The controller itself is a very sturdy looking PCB with wide traces and nicely machined brass buss bars backing up an array of MOSFETs. A microcontroller performs quite a few functions; aside from timing the pulse, it can control the energy delivered, read the resistance of the 8AWG leads for calibration purposes, and even detect bad welds. The welder normally runs off a foot switch, but it can also detect when the leads are shorted and automatically apply a pulse — perfect for high-volume production. See it in action below.

There may be bigger welders, and ones with a little more fit and finish, but this one looks like a nicely engineered solution.

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A Fix For The Lightweight Machine Tool Shakes

September 16, 2017 by 12 Comments

No matter what material you work with, the general rule is that with machine tools, the heavier, the better. Some people can’t afford or don’t want big tools, though, even with their natural tendency to reduce vibrations. That doesn’t mean something can’t be done to help the little tools, like reducing vibration in a contractor-grade table saw.

This one might seem a little outside the usual confines of the hackosphere, but nobody can doubt [Matthias Wandel]’s hacker chops and he really shows off his problem-solving skills with this one. His well-worn contractor-style table saw has had more than a few special modifications over the years, some of which left it with a shimmy sufficient to vibrate workpieces right off the table. He fashioned a friction damper for the saw’s motor from wood, complete with ball and socket joints to allow full movement of the blade height and angle. That didn’t quite do the trick, but his incremental approach finally found the right combination of factors, and the video below shows a saw now stable enough to balance a nickel.

If the name seems familiar but you just can’t place the hacks, check out [Matthias]’s recent wooden domino extruder, his shortcuts to tapping wood, or of course his classic wood gears layout software.

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Battery Management Module Hacked For Lithium-Iron Battery Bank

September 14, 2017 by 37 Comments

In a departure from his usual repair and tear down fare, [Kerry Wong] has set out on a long-term project — building a whole-house battery bank. From the first look at the project, this will be one to watch.

To be fair, [Kerry] gave us a tease at this project a few months back with his DIY spot welder for battery tabs. Since then, he appears to have made a few crucial design decisions, not least of which is battery chemistry. Most battery banks designed for an inverter with enough power to run household appliances rely on lead-acid batteries, although lithium-ion has certainly made some inroads. [Kerry] is looking to run a fairly small 1000-watt inverter, and his analysis led him to lithium-iron cells. The video below shows what happens when an eBay pack of 80 32650 LiFePo4 cells meets his spot welder. But then the problem becomes one of sourcing a battery management system that’s up to the charge and discharge specs of his 4s battery pack. We won’t spoil the surprise for you, but suffice it to say that [Kerry] really lucked out that only minimal modifications were needed for his $9 off-the-shelf BMS module.

We’re looking forward to seeing where this build goes, not least because we’d like to build something similar too. For a more traditional AGM-based battery bank, check out this nicely-engineered solar-charged system.

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Hacked Headset Brings VR To The Commodore 64

September 14, 2017 by 6 Comments

The venerable Commodore 64 got a lot of people started in computers, and a hard core of aficionados keeps the platform very much alive to this day. But a C64 just doesn’t have the horsepower to do anything more than some retro 8-bit graphics games, right?

Not if [jim_64] has anything to say about it. He’s created a pair of virtual-reality goggles for the C64, and the results are pretty neat. Calling them VR is a bit of a stretch, since that would imply the headset is capable of sensing the wearer’s movements, which it’s not. With just a small LCD screen tucked into the slot normally occupied by a smartphone in the cheap VR goggles [jim64] used as a foundation for his build, this is really more of a 3D wearable display — so far. The display brings 3D-graphics to the C64, at least for the “Street Defender” game that [jim64] authored, a demo of which can be seen below. We’ll bet position sensing could be built into the goggles to control the game too. Even then it won’t be quite the immersive (and oft-times nauseating) experience that VR has become, but for a 35-year old platform, it’s not too shabby.

Looking for more C64 love? We’ve got a million of ’em — case mods, C64 laptops, tablets, even CPU upgrades.

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In-Band Signaling: Coded Squelch Systems

September 13, 2017 by 18 Comments

In the first part of our series on in-band signaling, we discussed one of the most common and easily recognizable forms of audio control, familiar to anyone who has dialed a phone in the last fifty years – dual-tone multifrequency (DTMF) dialing. Our second installment will look at an in-band signaling method that far fewer people have heard, precisely because it was designed to be sub-audible — coded squelch systems for public service and other radio services. Continue reading “In-Band Signaling: Coded Squelch Systems” →