Heatsink Tester Shows Thermal Resistance Isn’t Futile

January 29, 2014 by Kristina Panos 13 Comments

[Bogdan] knows that it’s hard to model the cooling needs of any given project. It’s important to know how much heat a system can dissipate given the housing material, airflow opportunity, and the proximity of neighboring components. Inspired by an aluminium-walled enclosure that allows for mounted transistors, he devised and built a heatsink tester.

He’s using an ATXMEGA32A4U, a temperature sensor, and a IRF540 MOSFET. A specific power is dissipated across the transistor, and the temperature sensor measures the heatsink as close as possible to the transistor. Through the serial connection, he gets back the supply voltage, current, calculated power, DAC set, temperature, and calculated thermal resistance in the terminal.

[Bogdan]’s tester assumes that it is reading the ambient temperature, so the circuit needs to warm up first. He found that an hour is generally long enough to reach this point. He also found that the system exhibits high thermal inertia, so it regulates the DAC output based on the dissipated power.

The Robot Operating System (ROS) 101

January 29, 2014 by James Hobson 15 Comments

Ever heard about the Robot Operating System? It’s a BSD-licensed open-source system for controlling robots, from a variety of hardware. Over the years we’ve shared quite a few projects that run ROS, but nothing on how to actually use ROS. Lucky for us, a robotics company called Clearpath Robotics — who use ROS for everything — have decided to graciously share some tips and tricks on how to get started with ROS 101: An Introduction to the Robot Operating System.

The beauty of the ROS system is that it is made up of a series of independent nodes which communicate with each other using a publish/subscribe messaging model. This means the hardware doesn’t matter. You can use different computers, even different architectures. The example [Ilia Baranov] gives is using an Arduino to publish the messages, a laptop subscribed to them, and even an Android phone used to drive the motors — talk about flexibility!

It appears they will be doing a whole series of these 101 posts, so check it out — they’ve already released numéro 2, ROS 101: A Practical Example. It even includes a ready to go Ubuntu disc image with ROS pre-installed to mess around with on VMWare Player!

And to get you inspired for using ROS, check out this Android controlled robot using it! Or how about a ridiculous wheel-chair-turned-creepy-face-tracking-robot?

Satisfying Way To ‘Build’ Projects

January 29, 2014 by Kevin Darrah 35 Comments

When you’re writing code for your next big creation, chances are that you build/debug the project 100’s of times a day. Sure, the keyboard hotkey gets the job done, but is it really that satisfying? [Victor] sends in this quick project on turning an Emergency Stop Push button into a ‘Build’ button.

From the looks of it, this project uses a Teensy 2.0, which sports an ATMEGA32U4. Since this part features a USB controller, it is a piece of cake to get it to mimic a keyboard. The circuit is also very simple; the pushbutton contacts are wired from ground to a digital input. On detection of a ‘press’, the Teensy will send out the keyboard combination to build your project: Ctrl-B, F7, etc… If you prefer working within the Arduino IDE, this could upload sketches as well (Ctrl-U).

Adding a little fun to ‘building’ your projects does come at a cost though. Besides forfeiting a Teensy, you also have to give up a precious USB port. [Victor] does mention Bluetooth, but that could break your budget for this sort of project. A possible alternative to the Teensy could be to implement Virtual USB on a low-cost standalone Arduino.

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Tesla Coil Auto-Winder

January 28, 2014 by James Hobson 18 Comments

tesla winder

Tesla coils are awesome. But if you’ve ever built one, you know how tedious winding the secondary coil is. So [Krux] decided to build a machine to do it for him.

He’s currently working on his first Tesla coil — code-named Project Icarus — he doesn’t have all the logistics ironed out quite yet, but he’s been slowly collecting the components. What he does know is that he wants to use a 4.5″ secondary coil, using 22AWG magnet wire, meaning that’s a lot of turns! Since he’s also a member of a local hackerspace, he decided to make it a modular machine that can wind different sized coils for different sized projects.

Essentially, he’s built his own CNC lathe to accomplish this, well, missing one axis. There’s the main rotary axis, and a wire-guide that moves along it ensuring the coils are wrapped tightly without gaps. It’s an impressive build and you can tell he’s put a lot of thought into the design — He’s even got a semi-flexible 3D printed motor coupler on the wire-guide axis, to help mitigate quick acceleration! The main rotary axis is also driven by a 3D printed herringbone style gear — similar to the style used on Printrbot extruders. The rest of the build is made of plywood and pegboard — allowing for even larger coils to be wound by shuffling around the components. He’s even got a full featured command console with manual/automatic controls and an LCD giving feedback on the coil being wound!

Stick around after the break to see [Krux] explain the fascinating build, and to see a fun time-lapse of an 814-turn Tesla coil winding!

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The 8 Bit Harmonica Blows In From Japan

January 28, 2014 by Adam Fabio 18 Comments

8bit-harmonica

From [Basami Sentaku] in Japan comes this 8bit harmonica. [Basami] must remember those golden days of playing Famicom (or Nintendo Entertainment System for non-Japanese players). As the systems aged, the contacts would spread. In the case of the NES, this would often mean the infamous blinking red power light. The solution for millions of players was simple. Take the cartridge out, blow on it, say a few incantations, and try again. In retrospect, blowing on the cartridges probably did more harm than good, but it seemed like a good idea at the time. We’d always assumed that the Famicom, being a top loading design, was immune from the issues that plagued the horizontal slot on the NES. Either [Basami] spent some time overseas, or he too took to tooting his own cartridge.

Blowing into cartridges has inspired a few crafty souls to stuff real harmonicas into cartridge cases. [Basami] took a more electronic route. A row of 8 microphones picks up the players breath sound. Each microphone is used to trigger a specific note. The katakana in the video shows the traditional Solfège musical scale: do, re, mi, fa, so, la ti, do. A microcontroller monitors the signal from each microphone and determines which one is being triggered. The actual sound is created by a Yamaha YMZ294. The ‘294 is an 18 pin variant of the venerable General Instrument AY-3-8910, a chip long associated with video game music and sound effects. While we’re not convinced that the rendition of Super Mario Bros’ water theme played in the video wasn’t pre-recorded, we are reasonably sure that the hardware is capable of doing everything the video shows.

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FaBrickation: Combining Lego And 3D Printing

January 28, 2014 by Eric Evenchick 29 Comments

While 3D printing gives you the ability to fabricate completely custom parts, it does have some drawbacks. One issue is the time and cost of printing large volumes. Often these structures are simple, and do not require completely custom design.

This is where the faBrickation system comes in. It allows you to combine 3D printed parts with off the shelf LEGO bricks. The CAD tool that lets you ‘Legofy’ a design. It creates directions on how to assemble the LEGO parts, and exports STL files for the parts to be 3D printed. These custom bricks snap into the LEGO structure.

In their demo, a head mounted display is built in 67 minutes. The same design would have taken over 14 hours to 3D print. As the design is changed, LEGO blocks are added and removed seamlessly.

Unfortunately, the tool doesn’t appear to be open source. It will appear for the ACM CHI Conference on Human Factors in Computing Systems, so hopefully we will see more in the future. Until then, you can watch the demo after the break.

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Hackaday Visits The Clark Magnet High School

January 28, 2014 by Brian Benchoff 26 Comments

school

Thought Hackaday’s trip to LA was all about hackerspaces, parties, and rummaging through piles of awesome junk? Nope. We’re also tasked with some community outreach that brought us to the Clark Magnet High School in Glendale, CA.

This isn’t your usual high school. Each year, it accepts around 300 new freshmen (grade 9) from the other high schools in the Glendale district. Selection is done through a lottery system, ensuring it’s not just the kids “on the good side of the tracks” or whose parents are active in the PTA that are selected; about 52% of the students at Clark can be classified as at or below the poverty line.

The curriculum? Instead of stopping at the classical comprehensive high school education, the students at Clark Magnet are focused primarily on the STEM fields. They’re also the home base for Team 696, a FIRST robotics team that has done very well in robotics competitions. A few mentors from JPL and IBM help the students out on their projects, and the head of Clark’s engineering program, [David Black], as well as the principal, were once students themselves.

As far as their engineering program goes, they have a very impressive setup; their workshop features a Haas minimll with a 10-tool carousel, a huge CNC wood router, more than one 3D printer, a small woodshop, a CAD classroom – in short, enough tools to make just about anything. Because Clark Magnet is in sunny California, they’ve been able to get a few grants and build a 358kW peak solar array behind the football field. It’s enough to keep the lights on, and the electric bill down, allowing them to hire an additional teacher or two.

In addition to an impressive engineering/shop class, there’s also an audio and video production suite filled with Mac Pros, cameras, mixing boards and 96 Terabytes of storage. It’s not an exaggeration to say this high school is better equipped than some colleges.

Clark also does some other very interesting stuff outside of class; they’ve launched and recovered high altitude balloons, traveled to elementary schools to play with Lego robots, and some students also have impressive home-built projects they bring in to tinker with. We saw a homebrew quadcopter and a very awesome Mecanum wheel robot that we expect to see in the Hackaday tip line shortly.

Despite how awesome the Clark engineering department is, and how capable the students are, they’ve said the FIRST robotics team has been getting a lot of flak from the rest of the maker community. Apparently some people see an amazing engineering program as a waste of resources. From our short time at Clark, we think nothing could be further from the truth. These students are quickly becoming experts at CAD design and CNC operations. They’re competent embedded programmers and well on their way to becoming awesome engineers. Students who don’t want to build a robot or program firmware get involved in project planning, marketing, and all the rest of the business that goes into running a initiative of this size. It’s a truly awesome program, and I have to say I’m a little bit jealous I didn’t graduate from Clark.

Gallery of pics and two videos below: going over the workshops at Clark and a robot project. Our fanboyism for Clark also demands we link to the (very small and very resonable) Kickstarter the FIRST robotics team is using for their 2014 budget.

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