Geeks Living Off The Grid Are Hard On Batteries

May 19, 2012 by Caleb Kraft 37 Comments

Many of you will remember [Mikey Sklar] from the multitude of times he’s been on hackaday. What you may not have noticed is that he is an ubergeek, living off the grid.

He has Solar PV battery bank, three electric vehicles, a shipping container loaded with battery powered tools and a small army of iRobot Roomba’s for cleaning. Getting the maximum lifetime out of a battery by removing sulfation is essential to keep expenses down.

Keeping expenses down is nearly a full time job when trying to live the homestead lifestyle. Our current culture makes it extremely difficult to survive completely on self made/grown things and bartering. They seem to be doing pretty well though. One way he can reduce his costs while still getting to enjoy some modern gadgets is to get longer life out of his batteries. He does this by using a capacitive battery charger and desolfator that he designed and affectionately calls “Da Pimp”. He also brings in a little bit of income by selling kits!

A capacitive charger behaves like a constant current power supply dynamically adjusting the voltage to get over the batteries internal resistance. Plus there is a pulse from the AC/DC conversion. This allows for old batteries to last longer and for dumpster dived to be used as replacements. Capacitive chargers are small, silent and super efficent (up to 60% more so than cheap transformer based chargers).

Of course, [Mikey] is a supporter of sharing information so you can also go to his site and download the schematics,bill of materials, gerber files, and files for the housing, to build one yourself.

Mixing Colors On The Reprap

May 18, 2012 by Caleb Kraft 14 Comments

3d printing has come huge strides in ability to construct detailed objects. Unfortunately, color is still a considerable limitation. Here, some people at the Reprap blog are having fun coming up with an extruder head that actually mixes two colors as it deposits them. Don’t confuse this with the dual head that Makerbot is touting that allows you to switch colors on the fly, this is a single head that actually has a cavity where the material is melted, then stirred to create a combination of the two. It is an interesting method of overcoming a limited supply of colors.

Having this extra stirring chamber means that there would be a small amount of material wasted any time that you wanted to make a change to the color, as it would have to be purged. There are some interesting thoughts in their comments on how to use this extra material most efficiently.

Building A Ranque-Hilsch Vortex Cooling Tube

May 17, 2012 by Caleb Kraft 44 Comments

The Ranque-Hilsch vortex tube is an interesting piece of equipment. It can, without any moving parts or chemicals, separate hot and cold compressed gasses that are passed through it. Interestingly enough, you can cobble one together with very few parts for fairly cheap. [Otto Belden] tossed one together in a weekend back in 2009 just to see if he could do it. His results were fairly good and he shared some video tutorials on its construction.

His latest version, which you can see in the video below, takes compressed air at about 78degrees and spits out about 112degrees on the hot side and 8degrees on the cold side. Not too bad!

Continue reading “Building A Ranque-Hilsch Vortex Cooling Tube” →

Making A Miniature X-Ray Tube From Scratch

May 17, 2012 by Caleb Kraft 39 Comments

We know that most of you will have no reason to ever make a miniature X-ray tube. However, we also know that many of you will find this video mesmerizing like we did. [Glasslinger] does a fantastic job of explaining the entire process of creating the mini x-ray tube from, procuring the uranium glass and tungsten stem, creating the filament from scratch, all the glass work, and the testing.

Admittedly, most of us here at hackaday won’t go any further than admiring the craftsmanship, though we’re curious to see what [Adam Munich] has to say when he sees this story.

If you enjoyed the tube construction in the video, be sure to check out [Glasslinger’s] other videos. He makes all kinds of tubes in his shop and usually shares so much information along the process that each one has useful information beyond that particular project. Another crazy part is that he has made most of his own tools, including his glass lathe.

We really shouldn’t have to point out that X-Rays are dangerous. Don’t mess with them unless you have researched how to do it safely.

Turning An Oscilloscope Into A Logic Analyzer

May 16, 2012 by Brian Benchoff 5 Comments

Sooner or later, you’re going to need a logic analyzer. If you don’t have a Bus Pirate or Logic Sniffer lying around, [Joonas] has a great MacGyverism that turns an oscilloscope into the simplest logic analyzer ever.

The basic premise of the build is tying four digital lines to the analog input of an oscope. This is done with a 74HC126 buffer that provides a high impedance input for the logic probes and outputs the four-bit status of each logic channel. With a few resistors in an R-2R network, the state of four digital lines can be easily read.

[Joonas] included the source code to turn his Picoscope 2000 into a logic analyzer, but there’s no reason why this couldn’t be done with any digital scope that has a serial output. Not bad for a very, very simple logic analyzer – just one chip and a handful of resistors – that costs less than $5.

Designing A Self-replicating Milling Machine

May 14, 2012 by Brian Benchoff 14 Comments

For his senior design project at Swarthmore College, [Julian] decided to build a metalworking equivalent to the RepRap. [Julian]’s final project is a self-replicating milling machine, and hopefully giving some serious metalworking power to all the makers with CNC routers and RepRaps out there.

At first glance, [Julian]’s mill doesn’t look like something you would find in a machine shop. The machine is built around a tetrahedral machine tool frame, giving the machine an amazing amount of stiffness with the added bonus of a degree of self-alignment. The spindle and motor are off-the-shelf units, but the entire bed assembly is made by [Julian] himself.

Right now, [Julian] still considers his project a very early prototype; there’s still a bit of chatter issues he’s working out, and the cost of the finished machine – about $1200, not including many hours of fine tuning – means it isn’t as competitive as other options. Still, [Julian] made a mill from scratch, and that’s nothing to scoff at.

USB Connectivity That Is So Very Very Small

May 11, 2012 by Mike Szczys 23 Comments

Using FTDI chips as a USB to Serial solution is nothing new, but this MicroFTX board takes the footprint to a new low. If you’re space limited this should have no problem fitting into your project. But if you plan to use it for prototyping we predict it’ll be lost in the parts bin forever as soon as you take your eyes off of it.

The USB Mini-B connector is becoming quite popular with hobby electronics these days. But here [Jim Paris] chose to use its little brother, the USB micro connector. Want to put this together by hand? How are you with 0402 footprints and QFN chips? In fact, there’s a ground pad on the bottom of that IC which means you really need to use a reflow oven to do the job right.

Aside from the diy-unfriendly fabrication size, we do like the design. There are four output pins (voltage, ground, TX, and RX) with a set of four solder jumpers to configure them. It can be powered from the USB port or an external connection, with the option for 5V or 3.3V output.

[Thanks John]