Three Axis Position Indicator With Digital Calipers

January 19, 2014 by 22 Comments

[Malte] just finished a little project for his Wabeco F1200 milling machine: a compact external display for three digital sliding calipers (Translated from German). As you may have already guessed, [Malte] was lucky enough to be able to fit disassembled calipers onto the machine and use them for positioning. Before embarking on this adventure, he noticed that there were similar projects present on the internet, but all of the calipers used had different data interfaces and protocols. The calipers that [Malte] bought have a mini USB connector, even though the interface itself isn’t USB. As he couldn’t find any information on that interface, he turned to his oscilloscope to decode the protocol.

[Malte] then built an AVR-based platform that reads out the three calipers and shows the position data on the dot matrix LCD shown above. The AVR firmware is written in a mixture of Basic and assembler language. The source code, schematics, and other resources can be downloaded from the project’s web page. We are impressed on the professional aspect of the final result.

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Reviving A Stubborn Laptop Battery

January 19, 2014 by 42 Comments

We’ve all gotten bored of certain toys and left them on the shelf for months on end. But what do you do when this prolonged period kills the batteries? Well if you’re [Andrew] you take apart the battery pack and bring it back to life!

[Andrew] picked up one of those Panasonic Toughbooks awhile back and although it’s hardly a top of the line laptop specs-wise, it does have some pretty cool features: it’s shock-proof, splash-proof, and extreme-temperature-proof. It even had a touch screen before touchscreens were cool. Despite its durability, however, the laptop was left to sit for a bit too long, and the battery pack no longer accepted a charge.

[Andrew] quickly disassembled the battery pack and began measuring the cells with his trusty multimeter, assuming just one cell had gone bad. Curiously though, no cells reported 0V. What he did find was that each cell and sub-pack reported 2.95V, which is 0.05V below the “safe operating limits” of typical lithium ion cells. Continue reading “Reviving A Stubborn Laptop Battery” →

An Elegant Kegerator For Less Than $100

January 19, 2014 by 6 Comments

keg

Looking for a fun weekend project? How about making your very own kegerator for about $100? Well, minus the keg of course.

First you’ll need a run of the mill mini-bar fridge. These can be had for free if you prowl student neighborhoods at the end of a semester; it’s amazing what you can find being thrown out. Next you’ll have to modify it a bit: remove the shelving and pop a hole in the top. The trickiest part is building the top out of wood, although [jypuckett] shows us that it’s really not that difficult, and wood stain is your friend!

The most expensive part of the build is probably going to be the fittings, hoses, and tap, but that’s a small price to pay for your very own kegerator.

While it’s not quite as fancy as this over-engineered kegerator, the six-tap freezer chest kegerator, or as vintage as this 1950’s General Electric fridge kegerator, it is a great example of making one for cheap, that works, and looks good.

It also raises the question: if it’s this easy to make, why haven’t you made one yet?!

The Tiniest SD Card Locker

January 18, 2014 by 45 Comments

sdlocker-tiny

In case you weren’t aware, that little ‘write protect’ switch on your SD cards probably doesn’t do anything. It’s only a switch, really, and if an SD card reader doesn’t bother to send that signal to your computer, it’s completely ineffective. Then there’s the question of your OS actually doing something with that write protect signal.

The better way to go about write protecting an SD card is using the TMP_WRITE_PROTECT bit on the SD card’s controller. [Nephiel] came up with an amazingly small device to set that bit, with the entire circuit fitting inside an old Playstation memory card.

[Nephiel] based his project on [Karl Lunt]’s SD Card Locker we saw late last year. [Karl]’s SD Locker uses an ATMega328 microcontroller, a pair of AA batteries, and an SD card socket to perform the bit toggling. This is still a very small device that fits inside an Altoids tin, but [Nephiel] thought he could make it smaller.

The new and improved version uses an ATTiny85 for SPI access to the SD card. A single button and LED serves as the user interface: with the LED off, the SD card is writable. Press the button, the card is locked, and the LED lights up.

0.19 Leagues Under The Sea

January 18, 2014 by 20 Comments

ROV

[Doug] and [Kay] have been building a steel 70-foot sailboat for the last few years, and since it’s a little too cold to work outside their home/shop in Oklahoma, they’re bringing their projects inside for the winter. Until it warms up a bit, they’re working on an underwater ROV capable of diving to 3000 feet below the waves, maneuvering on the ocean floor, and sending video and side-scan sonar back to their homebuilt ship.

Like [Doug] and [Kay]’s adventures in shipbuilding, they’re documenting the entire build process of ROV construction via YouTube videos. The first video covers the construction of a pressure vessel out of a huge piece of 10″ ID, half inch wall steel pipe. The design of the ROV will look somewhat like a torpedo, towed by the ship with cameras pointing in all directions.

For communication with the surface everything is passing over a single Cat5 cable. They’re using an Ethernet extender that uses a twisted wire pair to bring Ethernet to the ocean bottom. With that, a few IP webcams relay video up to the ship and a simple Arduino setup allows for control of the ships thrusters.

The thrusters? Instead of an expensive custom solution they’re using off the shelf brushless motors for RC cars and planes. By potting the coils of a brushless outrunner motor, [Doug] and [Kay] found this solution makes an awful lot of sense; it’s cheap, fairly reliable, doesn’t require a whole lot of engineering, and most importantly cheap.

Bunch of videos below, or just check out [Doug] and [Kay]’s progress on their slightly out-of-date blog.

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Peristaltic Pump Moves Fluids Uphill Both Ways

January 18, 2014 by 44 Comments

Here’s a skill we should all probably have for after the apocalypse—the ability to build a cheap peristaltic pump that can transport highly viscous fluids, chunky fluids, or just plain water from point A to point B with no priming necessary. That’s exactly what [Jack Ruby] has done with some fairly common items.

He started with a springform cake pan from a thrift store, the kind where the bottom drops out like that centripetal force ride at the carnival. He’s using 2″ casters from Harbor Freight mounted to a block of wood. The casters go round and squeeze fluid through the hose, which is a nice length of heat-resistant silicone from a local homebrew shop. He’s currently using a drill to run the pump, but intends to attach a motor in the future.

[Jack]’s write-up is very thorough and amusing. Stick around to see the pump in action as well as a complete tour. You can also pump colored goo if you’re out of beer materials.

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USB Datalogging With Arduino Using V-USB

January 18, 2014 by 18 Comments

Adding USB functionality to your Arduino projects used to be a pain, but thankfully, the V-USB project came along and gave your ATMEGA328 the ability to control the USB lines directly and mimic simple (low-speed) USB peripherals. [Ray] shows an implementation of the V-USB project by logging the status of the Arduino’s I/O pins to an open Excel spreadsheet

V-USB (Virtual USB) is especially useful for those of us who build standalone Arduino projects with the ATMEGA328. Unlike the Arduino Leonardo and its ATMEGA32U4, the ATMEGA328 does not have a built-in USB controller. The circuit required to tie into the USB lines is made up of just a few basic components, and [Ray] provides a reference schematic and BOM to get you started. The Arduino is programmed to mimic a keyboard, so the datalogging is achieved by allowing the Arduino to ‘type’ the data into an open Excel spreadsheet. In this example, the status of 8 digital pins and all 6 Analog Input pins are logged.

For those of you who prefer the PIC microcontroller and are in a similar position of not having a built-in USB controller, there is the 16FUSB project to help you out.