Singing Robot

July 25, 2011 by Kevin Dady 19 Comments

The 4DOF CXN-I anthropomorphic robot arm in the Mechatronics Lab at FICES-UNSL (Engineering faculty, San Luis National University, Argentina) was built from scratch, and it is still a work in progress to teach and learn about mechatronics , in order to build another, more robust and precise arm in the future. When one of the students working with the device thought “hey, these motors are quite noisy, aren’t they? let’s put them to work towards something more useful”.

Armed with some guitar tabs, a robot and some noisy servos, [Guille] got the robotic arm to sing a little song raised a couple of octaves, and included it in the introduction video. Because hey, whipping a metal arm around like that is pretty mechanically strenuous, and its not all that great for the servos either.

Join us after the break for a quick video, the singing starts about 58 seconds into the show.

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Hacking 14 Year Old Power PC Mac Back To Life

July 24, 2011 by Kevin Dady 63 Comments

For a while now I have been battling a dying 2.6Ghz dual core computer, but due to laziness and budget I just let it ride. At first it would occasionally crash in games, then it got to where it would crash during routine activities. After a year of this it would nail 105 degrees C in like 20 seconds and that is where the drama starts!

I threw my 2ghz “electronics” computer into my main machine’s case and used that for a few months. It’s motherboard had suffered from every electrolytic capacitor on it being puffy, but it has worked fine for nearly 5 years. I was surprised by the sound of what ended up being 2 caps blowing off of the geforce 7600 video card. In shock and excitement I removed the blown caps, slapped her back in and got another 4 months out of it before 2 more capacitors blew and took out a voltage regulator (and who knows what else with it).

Only armed with the craptop, I was stuck in a pickle! Then a co-worker came up to me and said “hey man you want this mac I only want its zip drive”. Well of course, going bonkers without my avrgcc, datasheets, and calculators, I took on the 14 year old Apple Power Macintosh 9600/300 as my bench machine, and I will now show you how I turned it from a novelty relic to a daily useful machine after the break.

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PLL 101

June 21, 2011 by Kevin Dady 14 Comments

[Jeri Ellsworth] and former Commodore Computer engineer and current full time tinkerer [Bil Herd] have a little chat on skype covering the 101’s of Phase Lock Loops in this hour long video. PLL’s are handy for many applications, but their basic use is to keep clock signals in sync.

Topics covered include: Why we care, a basic explanation for the CD4046, capture ranges, and meta stability. Examples from analog tv, to clock recovery, finding falling edges and FPGA’s. This thing is jam packed full of information.

With talks of future episodes and a quick tour of [Bil’s] bench this is something to not miss. Join us after the break for the video!

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VGA Testers For The Children

May 31, 2011 by Kevin Dady 11 Comments

Recently on our Hack A Day forums a member asked about getting some VGA testers made in our “Request and Commissions” forum for a charity called the World Computer Exchange, who take old office PC’s and freshens them up to be used by children in developing countries for their education.

I sort of wanted to do a no brainier electronics build as I had been working on that Apple II weather display for quite a while at that point. I say no brainier because I decided to use one of the many already designed vga testers out there and all I really had to do was get it to fit in whatever box we ended up with.

I choose the deogen because it was already featured on Hack A Day, supports multiple raster patterns and resolutions (640×480 through 1280×1024), is already pretty darn small, and uses an ATTiny 2313 which is good because I am already set up for AVR micro controllers. For a case I choose to use some plastic “Ice Breakers” mint boxes, which due to their oval shape makes it quite a bit smaller than an altoids tin. The challenge is on to shove a PCB, switch, 9V battery, 2 buttons and a vga connector in the cramped space.

Join us after the break for a pile of pictures and some build notes.

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A Bright Idea

May 30, 2011 by Kevin Dady 43 Comments

[Jeri Ellsworth] had a bright idea – a brain-activated light bulb that floats above your head. While out and about, she saw some guy with a video game icon attached to metal rod sticking out of his backpack. The rod made the icon appear to be floating above his head (think The Sims), which was the inspiration for this LED powered light bulb. The bulb is connected to a metal rod, as well as a metal hoop which is springy enough to keep a pair of electrodes snugly attached to your head.

Those electrodes, along with a third probe used for noise reference, are hooked up to a AD620 instrumentation amplifier. With the help of op amps, it modulates the red or green LEDs that are attached to the back side of the light bulb. The end result is an amusing way to show brain activity while being grilled on a Q/A panel, or while just wandering around taking in all the amazing sights presented at Maker Faire.

Join us after the break for a video demonstration.

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Hidden Messages In Audio

May 26, 2011 by Kevin Dady 24 Comments

[Alex] tiped us off about the evil sounding noises coming from http://www.thedarkknightrises.com/. when you go there your pretty much greeted with a wav file and if you have a quick eye on the status bar its pretty easy to get the direct link to the file and download it. Thats all great, but why would you want to?

Well if you play back the file in a program that supports spectrograms (like audacity) you will find that there is a twitter hash hidden within the audio spectrum, that presents itself as plain text in a pretty well rendered font. Of course this leads you to another part of the site where yet another puzzle awaits you.

While this is all an interesting way to stir up buzz about the upcoming (Batman) movie, we found hiding plain text in an audio file pretty wild, though its been done before or better such as the post we had not too long ago about Ham’s packing QR codes in a similar way.

Simple Bench Power

May 24, 2011 by Kevin Dady 30 Comments

When dealing with electronics you need 1 key thing, electricity. For quite a while now if I needed 5 volts I would just grab my homebrew arduino, but that is not always handy and its tethered to the pc and it does not have 3v. If I wanted 3 volts, now I am digging around looking for my UBW32 which does have 3v3 but now I have a 50$ microncontroller with very small regulators (so therefore only small loads) dangling around just for power, and its a mess.

So I need just a board that takes some DC from a wall wart and regulates it to usable voltages, and I set about to make it. This regulator board puts out +5, +3.3, variable and negative variable voltages, is pretty easy to make, and make a nice addition to the bench. (until I can get a real bench supply someday)

Now I know this is not ground breaking hackery, but I hope it helps someone out there, join us after the break to see what’s going on.

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