Month: January 2012

Controlling An LED Matrix With An Android Phone

January 23, 2012 by 13 Comments

Even though everyone with a smart phone has a small, powerful computer in their pocket, we haven’t seen many applications of this portable processing power that use the built-in camera. [Michael] decided to change this and built an LED matrix that displays the data coming from the phone’s camera.

For the build, [Michael] used two 32×32 LED panels from Adafruit along with an IOIO and an Arduino. To build the Android app, [Michael] used the Android OpenCV computer vision library that grabs an image from the Android camera and downsamples it to 64×32 pixels. This data is transferred over a serial connection from the phone to the IOIO and again from the IOIO to the Arduino. Even though each frame is 1024 bytes, [Michael] still gets around four frames per second on his LED matrix display.

After the break you can check out the results of [Michael]’s build. The video is a little choppy because of the frame rate issue, but it’s still an interesting build in the Android software development category.

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Maximite Harkens Back To The Days Of BASIC

January 23, 2012 by 49 Comments

Any self-identified geek that spent some time in the 80s will tell you how they used to type out programs into their ‘microcomputer’ with BASIC. It was a simpler time when a computer’s raison d’etre was simply being a BASIC interpreter. These days are long past us now; you can’t simply turn on a computer and have it load a BASIC prompt anymore. This is where [Geoff]’s Maximite single board computer comes in. It’s a tiny little box that whose only purpose is to play around with BASIC.

[Geoff]’s used a PIC32MX microcontroller with 128k of RAM for the CPU of his Maximite. Unlike an Apple ][ or TRS-80, the Maximite version of BASIC can do floating point arithmetic out of the box. To connect to the outside world, the Maximite has VGA or composite out to display the BASIC interepreter. A PS/2 keyboard port provides the input, and a USB port and SD card can be used to load and save programs from a PC.

The Maximite includes a 20-pin breakout for whatever IO you can imagine. This is duplicated on [Geoff]’s mini Maximite that is designed to be the retro throwback of an Arduino. We though those were called BASIC stamps, but if it gets kids programming, we’ll let it slide.

3D Printed Helicopter Blades

January 23, 2012 by 40 Comments

If you’re like us, you’ve been infatuated with the small RC helicopter you picked up on Amazon up until the point where it careened off a wall and broke its blades. Now that you’re wondering about what to do with that small pile of plastic, metal, and electronics, why not print some helicopter blades on your 3D printer?

[Taylor] printed these blades on his Utilimaker, but we don’t see why they couldn’t be printed on a Makerbot or other RepRap. The first set of printed blades worked on the top rotor, but they were too heavy when all four blades were replace. The parts were edited in netfabb using a 0.08mm layer height and now they’re working perfectly. As far as free tools go, Slic3r is the new hotness for .STL to Gcode conversion and now that [Taylor] put the files up on Thingiverse, anyone can print a set of spare blades.

Check out [Taylor] comparing his printed blades to the stock ones that came with his awesome heli after the break.

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Shove A Hub Into That Keyboard

January 22, 2012 by 30 Comments

As masters of technology, our desks are often cluttered with odds and ends. We have cables spewing out of every nook, and our computer ports full. The last thing we really want is more stuff getting in the way or buried under piles of technical documentation when adding something like a USB hub. That is where [Michael] comes in, shoving a small USB hub into his Logitech keyboard.

The keyboard is already USB, and the hub has 3 forward facing ports and a fourth single port in the rear. Taking the 2 devices apart he used the already there USB cord from the keyboard replacing the input cord of the hub. Then he removed the rear port and directly wired his keyboard onto the hub.

From there, its just a matter of figuring out where he wanted the hub, and cutting out the plastic. He used a knife, and had fond memories of some minor cuts, which leads us to recommend being (more) careful. A little application of fire to blade goes a long way.

Once the keyboard is back together he has a convenient 3 port hub on the back of his keyboard that looks factory and saves clutter.

Make A Simple O-scope With A FTDI Board And A Couple Of ADC’s

January 22, 2012 by 25 Comments

[RandomTask] has posted a nice tutorial on how to use a FTDI serial to usb converter, and a couple analog to digital converters to make a simple software oscilloscope. Using a “Universal Serial to USB converter” and one of many FTDI break out boards, he first reprograms the chip using FTDI’s programming software to put the device into a FIFO (first in first out) mode.

From there a pair of ADC0820 8 bit digital to analog converters are wired up, and input is fed to a couple 555’s for testing. It should be noted that there is no input protection, so things like voltages above 5 volts, or negative voltages are a big no-no with this setup. It still could be very handy while working with micro controllers or other digital circuits.

Data is then sent to the computer and displayed using a VB.net program, which has some basic features like scale and triggering, but also contains a couple bonuses like Calc Freq and Calc V delta calculation.

Many people have these little serial to usb converters, and might be in need of a simple scope. If you’re one of them, then you can cobble this together pretty darn quickly, and cheaply.

Weekly Roundup 1/21/12

January 21, 2012 by 2 Comments


In case you were asleep at the wheel, here are our top stories of the week.

Our most popular post was one that shows you how to make your own ‘personal assistant’ using Wolfram Alpha, text to speech software, and the phone network. It still won’t get your coffee though. You’ll just have to do that yourself.

Coming in at second place was a post about how to use your Android camera phone as a Geiger counter. Of course, this hack will work with any device that uses a CMOS sensor to do its imaging but they have gone and wrapped it up into a nice app.

Do you have access to a laser cutter and a burning desire (pun intended) to make gears? In this post Alex makes some acrylic gears using an Epilog laser cutter.

When is our government going to get it through their heads that we don’t want the internet to be controlled by a small group of corporations? Probably when the lobbyists stop giving them money by the boat load to do just that… It seems like several times a year a bill comes through that would severely restrict the internet or would at least allow someone to shut down a website without any sort of due process. Luckily, groups like the EFF are paying attention and are well organized for getting the word out there. This post was our stand against the current bills that threaten our internet freedom.

Finally, on a lighter note, we have a post about how to do ultrasonic welding on the cheap using a ‘heat staker’ and a small drill press.

PVC Magnetometer To Measure Magnetic Storms

January 21, 2012 by 26 Comments

In the hopes of getting a heads up on when the aurora borealis will be visible from his back yard, [Alex] built a magnetometer to measure disruptions in Earth’s magnetic field. The build is extremely simple, too. It’s amazing what you can build with a few components and a trip to the dollar store.

The design or [Alex]’s project is called a torsion magnetometers. In this setup, two mirrors are affixed to a permanent magnet connected to a string. A laser is shone onto the mirror and is reflected back to an array of sensors. In [Alex]’s case he used a simple laser pointer and a pair of photoresistors encased in a PVC tube.

[Alex] has been running his magnetometer in his back yard for over a month now and has the data to prove it. Luckily for [Alex], those graphs he has been generating may get a little more interesting. A coronal mass ejection is coming our way and is expected to hit today around 22:30 UTC. We’ll go outside to look for an aurora, but we’re sure [Alex] will be glued to his laptop tonight.

Check out the CGI visualization of [Alex]’s magnetometer after the break

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