World Maker Faire: We Annoy The DIWire Crew

September 24, 2013 by Brian Benchoff 7 Comments

diwire

Last year at Maker Faire we ran into the folks from Pensa Labs, the crew behind the very cool DIWire CNC wire bender. They were back again in full force this year with a new, improved, and soon-to-be commercially launched wire bender.

The first time we saw the DIWire it was a very cool piece of kit, but something that might not hold up to the rigours of a production environment. The latest version, a 14×8.5×5.5 inch machine designed to be set into a table, allowing for rapid manufacturing of nearly any shape imaginable bent into 1/8″ and 1/16″ steel wire.

Making any shape with the DIWire is extremely simple: if you have an SVG file, just import it into the software, define a few points along a path, and slip in a length of wire. One of the guys from Pensa was able to re-create the Hackaday logo is a few minutes.

It’s an impressive piece of kit that a few makers, hackers, and architects are using to build structures that can’t be made any other way. The DIWire will soon be released to the public, so check out their site for updates.

DIY High Stability Timebase Hack For ~$25. Why? Frequency Stability Matters!

September 23, 2013 by Todd Harrison 25 Comments

If you have an old “Racal-Dana 199x” frequency counter or similar 10 MHz internally referenced gear with a poor tolerance “standard quartz crystal oscillator” or bit better “temperature compensated crystal oscillator” (TCXO) you could upgrade to a high stability timebase “oven controlled crystal oscillator” (OCXO) for under $25. [Gerry Sweeney] shares his design and fabrication instructions for a DIY OCXO circuit he made for his Racal-Dana frequency counter. We have seen [Gerry] perform a similar upgrade to his HP 53151A, however, this circuit is more generic and can be lashed up on a small section of solderable perf board.

Oven controlled oscillators keep the crystal at a stable temperature which in turn improves frequency stability. Depending on where you’re starting, adding an OCXO could improve your frequency tolerance by 1 to 3 orders of magnitude. Sure, this isn’t as good as a rubidium frequency standard build like we have seen in the past, but as [Gerry] states it is nice to have a transportable standalone frequency counter that doesn’t have to be plugged into his rubidium frequency standard.

[Gerry’s] instructions, schematics and datasheets can be used to upgrade any lab gear which depends on a simple 10 MHz reference (crystal or TXCO). He purchased the OCXO off eBay for about $20 — it might be very old, yet we are assured they get more stable with age. Many OCXO’s require 5 V, 12 V or 24 V so your gear needs to accommodate the correct voltage and current load. To calibrate the OCXO you need a temperature stable variable voltage reference that can be adjusted from 1 to 4 volts. The MAX6198A he had on hand fit the bill at 5 ppm/°C temperature coefficient. Also of importance was to keep the voltage reference and trim pot just above the oven for added temperature stability as well as removing any heat transfer through the mounting screw.

You can watch the video and get more details after the break.

Continue reading “DIY High Stability Timebase Hack For ~$25. Why? Frequency Stability Matters!” →

OpenFuge: An Open-source Centrifuge

September 23, 2013 by Marsh 24 Comments

openFuge

Biohackers, fire up your laser cutters. [CopabX] has developed OpenFuge: a (relatively) low-cost, open-source centrifuge from powerful hobby electronic components. If you thought the VCR centrifuge wasn’t impressive, trolls be damned— OpenFuge can crank out 9000 RPM and claims it’s capable of an impressive 6000 G’s. [CopabX] also worked in adjustable speed and power, setting time durations, and an LCD to display live RPM and countdown stats.

And it’s portable. Four 18650 lithium cells plug into the back, making this centrifuge a truly unique little build. The muscle comes from a DC outrunner brushless motor similar to the ones that can blast you around on a skateboard but with one key difference; an emphasis on RPMs over torque. We’re not sure exactly which motor is pictured, but one suggestion on the bill of materials boasts a 6000 KV rating, and despite inevitable losses, that’s blazing fast at nearly 15V.

You’ll want to see the demonstration video after the break, but also make time to swing by Thingiverse for schematics and recommended parts.

Continue reading “OpenFuge: An Open-source Centrifuge” →

VCR Centrifuge

September 21, 2013 by Marsh 33 Comments

VCR’s practically scream “tear me open!” with all those shiny, moving parts and a minimal risk that you’re going to damage a piece of equipment that someone actually cares about. Once you’ve broken in, why not hack it into a centrifuge like [Kymyst]? Separating water from the denser stuff doesn’t require lab-grade equipment. As [Kymyst] explains: you can get a force of 10 G just spinning something around your head. By harvesting some belt drives from a few VCR’s, however, he built this safer, arm-preserving motor-driven device.

[Kymst] dissected the video head rotor and cassette motor drive down to a bare minimum of parts which were reassembled in a stack. A bored-out old CD was attached beneath the rotor while a large plastic bowl was bolted onto the CD. The bowl–here a microwave cooking cover–acts as a protective barrier against the tubes spinning inside. The tube carriers consist of plastic irrigation tubing fitted with a homemade trunnion, which [Kymyst] fashioned from some self-tapping screws and a piece of PVC. At 250 rpm, this centrifuge reaches around 6 G and best of all, gives a VCR something to do again. Take a look at his guide and make your own, particularly if your hackerspace has a bio lab.

Polyurethane Protecting PCBs

September 20, 2013 by Brian Benchoff 29 Comments

PCB

What you see above is a home-made PCB. No, this isn’t an example of a terrible toner transfer job, but rather evidence of the ravages of time. This board is seven years old, and the corrosion and broken traces show it. Luckily, [George] already has seven years of environmental data for a cheap DIY soldermask.

Seven years ago, [George] took a piece of copper clad board, masked half of it off, and sprayed it with fast drying polyurethane. After drying, he put it on a shelf in his garage. The results were fairly surprising – the uncovered portion is covered in verdigris, while the coated half is still shiny and new.

[George] took this a bit further and experimented with other spray can coverings. He found Testors spray enable worked just like the polyurethane, burning off when the heat of a soldering iron was applied, and also passed for a professional PCB.

Modifying A Knock-off Battery Charger To Be Safer

September 16, 2013 by Phillip Ryals 30 Comments

Sometimes buying a low-cost clone off of eBay is a great option, but [Martin] wisely decided to test his counterfeit IMAX B6AC, and found it grossly lacking. His detailed breakdown shows an alarming array of problems, including poor design and construction, and a lack of warning if the balance circuit fails. In addition, the charger wasn’t properly calibrated. By using a precision multimeter, Martin found that the charger actually brought cells above critical voltage. So really, using a charger like this out of the box can both destroy your battery pack and/or start a fire. One other interesting detail – this model can only be calibrated once. Sweet features.

[Martin] detailed his fixes in a well-illustrated blog post. He first had to re-enable the calibration menu using this method which requires bricking the device first! Once un-bricked, however, he could do the recalibration using a voltage divider and a reliable power source.

This project really underscores the need for a precisely calibrated multimeter. Not only would [Martin] not have been able to test his charger properly, but the re-calibration wouldn’t have been as accurate as needed. As hobbyists, this is a reminder that we can only trust our tools if they are accurate.

Organizing Transistors

September 14, 2013 by Brian Benchoff 10 Comments

SAMSUNG

Late last year, [matseng] set up an interesting challenge for himself: design a new PCB every week, send it off to a fab house, and build a new project. It’s a grueling endeavor, but some of these projects are actually very useful and cool. One of the best so far is the TraId – a board that identifies a transistor type and pinout with a nice LED interface.

This build was partly inspired by Dangerous Prototypes’ Part Ninja, a board that determines the pinouts and values of transistors, resistors, caps, and diodes. The TraId is a much more cut down version usable only for transistors, displaying the orientation of the pins and type of transistor on a set of 8 LEDs.

Although the design is very sparse, we could imagine something like this being very useful in a hackerspace, lab, or anywhere else the gremlins of chaos come to reorganize parts drawers. If you’d like to build your own, all the required files are up on the gits.