Dealing With The Horrors Of PDFs By Binding Your Own Books

July 16, 2012 by 66 Comments

Looking at a few PDFs of data sheets, journal articles, or even complete books can be a pain. Not only do you have to deal with the torment of a PDF reader (we’re looking at you, Adobe), but a purely electronic document misses the beautiful tactile interface available in dead tree format. [samimy] put together an amazingly professional video showing us how to turn our convenient yet unwieldy PDFs into paperback books, perfect for a very accessible off-line reference.

[samimy]’s build is basically a few pieces of wood and C clamps designed to compress the printed PDF together. After drilling a few holes along the spine, he stitches the pages together with very strong thread and applies a little glue to the spine. After removing the pages from the press, [samimy] applied a piece of tape to the spine and had a very nice looking paperback book.

While [samimy] is using his binding jig for data sheets, we see no reason why a more prodigious tome couldn’t be created with his rig. A few pages of marbled paper and a leather cover would result in a beautiful and functional work of art that will be around long after you’re gone.

Rocket Telemetry From UAV Hardware

July 16, 2012 by 7 Comments

When we posted our call for rocketry hacks and builds, we expected to see a few altitude sensors and maybe a GPS module or two. Apparently, we forgot similar hardware is very popular in the remote-controlled aircraft world, and can be successfully added to a rocket as [Kevin] and his ArduPilot equipped J motor rocket showed us

The ArduPilot is a small Arduino comparable board designed for UAVs, quadcopters, and other whirligigs not powered by rocket motors. To get real-time telemetry from his rocket, [Kevin] attached a GPS receiver and an XBee transmitter. When launched on an H165 motor, [Kevin] was able to keep a radio lock on his rocket, allowing him to pull down data in real-time.

There are a few drawbacks to using the ArduPilot to collect flight data; the ArduPilot only reports ground speed, a somewhat useless feature if the vehicle is going straight up. Also, there is no way for [Kevin] to record data to an SD card; the ground team must be able to receive the XBee, lest bits of data go missing. For most rockets the radio issue shouldn’t be a problem. [Kevin] launched the same hardware on a J motor and was able to receive data from 3600 AGL.

Creating A Decadent, Insane, And Depressed Robot From Internet Ramblings

July 15, 2012 by 25 Comments

Have you ever wondered what a Tumblr written by a psychotic robot would look like? Wonder no more, because [Lars] has that all figured out.

A few years ago, [Lars] stumbled across lowbrow.com (now defunct, but mirrored here), an online confessional and bathroom wall meant to host people’s most private thoughts and actions anonymously. [Lars] wrote a script to pull a random lowbrow post down every minute and threw every unique result into a database.

With about 50 pages of the most depraved and depressing posts of questionable veracity, [Lars] trained a Markov chain algorithm to produce paragraphs that imitated the style of lowbrow contributors. This gave [Lars]  pages of computer-generated text describing the most decadent, depressing, insane, inane, but overwhelmingly human experiences possible. A few choice quotes from the output are:

The llama: nature’s random number generator.

Over 7000 watts of Ol’ Barry whining his ass cheeks to soften the blows.

All through school I was being pulled behind the local St. Benedictine  Monastary where I was afraid I don’t know what I thought was the founder pulls back from a discussion about homestarrunner.com

While [Lars]’ script wouldn’t pass a Turing test, we’ve met people who couldn’t do the same. As far as creating a real-life version of Hedonism Bot, HAL, and Marvin from Hitchhiker’s Guide, we’re thinking [Lars] hit the mark.

After the break you can check out a gallery of pics [Lars] put together of from his computer-generated text. You can also grab the full lowbrow corpus and the ruby script to build your robotic [Kerouac].

Continue reading “Creating A Decadent, Insane, And Depressed Robot From Internet Ramblings” →

A Detailed Tutorial On Speeding Up AVR Division

July 15, 2012 by 32 Comments

[Alan Burlison] is working on an Arduino project with an accelerometer and a few LEDs. Having the LEDs light up as his board is tilted to one side or another is an easy enough project a computer cowboy could whip out in an hour, but [Alan] – ever the perfectionist – decided to optimize his code so his accelerometer-controlled LEDs don’t jitter. The result is a spectacular blog post chronicling the pitfalls of floating point math and division on an AVR.

To remove the jitter from his LEDs, [Alan] used a smoothing algorithm known as an exponential moving average. This algorithm uses multiplication and is usually implemented using floating point arithmetic. Unfortunately, AVRs don’t have floating point arithmetic so [Alan] used fixed point arithmetic – a system similar to balancing your checkbook in cents rather than dollars.

With a clever use of bit shifting to calculate the average with scaling, [Alan] was able to make the fixed point version nearly six times faster than  the floating point algorithm implementation. After digging into the assembly of his fixed point algorithm, he was able to speed it up to 10 times faster than floating point arithmetic.

The takeaway from [Alan]’s adventures in arithmetic is that division on an AVR is slow. Not very surprising after you realize the AVR doesn’t have a division instruction. Of course, sometimes you can’t get around having to divide so multiplying by the reciprocal and using fixed point arithmetic is the way to go if speed is an issue.

Sure, squeezing every last cycle out of an 8 bit microcontroller is a bit excessive if you’re just using an Arduino as a switch. If you’re doing something with graphics or need very fast response times, [Alan] gives a lot of really useful tips.

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A Replica DJ Controller To Rule Them All

July 15, 2012 by 22 Comments

So like many followers of Hackaday, maybe you’re into electronic music. We’d dare to say though that few of you have the dedication of [adamdzak] as he decided to replicate [Sasha]‘s custom controller for the [Abelton Live] software package. Apparently it’s more difficult than taking apart your DJ Hero controller and hacking it to interface songs on your computer.

The “new” controller is named Apollo, and is meant to be a replica of Sasha’s Maven controller. The build process is well laid out in his post, and the results so far look quite incredible. What’s particularly interesting is the effort taken to reverse engineer this device without ever having been able to use it. Both from a mechanical standpoint and trying to figure out how the buttons are used to control the software must have been quite a challenge. Check out the video after the break to see this new controller in action. Continue reading “A Replica DJ Controller To Rule Them All” →

LVL1 Has A Rocketeers Group, Is Not Working On ICBMs.

July 15, 2012 by 5 Comments

We’re very familiar with the Louisville Hackerspace LVL1 here at Hackaday. From their GLaDOS-inspired sentient overlord, an evil box to filter the Internet, and a friggin’ moat, LVL1 is the closest we’ve got to a mad scientist heard cackling from a wind-swept castle on a stormy night. It turns out they also have a rocketry program. Now we’re just waiting for confirmation of their subterranean complex of missile silos.

The rocketery-oriented part of LVL1 spawned from a University of Louisville’s group. The goal of the group is to compete in the NASA University Student Launch Initiative, dedicated to competing against other teams to launch a scientific payload to 1 mile AGL. At the competition last May, the team placed 5th out of 42 teams and won the award for best website. We can’t wait to see what they come up with next year.

Even though the team is out of school for the summer, they’re still cooking up a few rocketry hacks. They’ve built a test stand to measure the thrust of off-the-shelf motors, kitbashed a few Estes Baby Berthas (very awesome and very easy if you have a laser cutter), and are starting a pulse jet project.

We’re assuming the LVL1 Rocketeers group is just a front for their yet to be unveiled moon-based “laser” project, but you can check out a few videos from the ULSI competition after the break.

Continue reading “LVL1 Has A Rocketeers Group, Is Not Working On ICBMs.” →

Android Oscilloscope Built From Parts Just Lying Around

July 14, 2012 by 36 Comments

So you need to debug a circuit and you don’t have an oscilloscope. That’s not a problem thanks to [retronics] $0 Android oscilloscope, made with parts he just happened to have lying around.

The heart of every modern oscilloscope is the ADC – the chip that takes analog input and outputs a digital signal. Every Android device has one of these converters connected to the microphone port. All [retronics] needed to do was solder up a 3mm headphone jack, wire in a few resistors, and attach a pair of alligator clips. After installing an oscilloscope app, [retronics] had a half decent ‘scope.

Yes, this is truly a poor man’s oscilloscope, and [retronics] probably won’t be debugging high frequency RF circuits with his Android microphone jack anytime soon. Low frequency stuff such as audio is where this ‘scope really excels; even more so if a small preamp is thrown into the mix.

You can check out [retronics]’ build after the break. Sure, it’s not something for precise and calibrated measurement, but sometimes you only need a tool that will do the job.

Continue reading “Android Oscilloscope Built From Parts Just Lying Around” →