Year: 2012

One-button Audiobook Player Made From A Raspberry Pi

November 1, 2012 by 35 Comments

[Michael Clemens] was looking for gifts for his Grandmother’s 90th Birthday. She is visually impaired and loves to be able to listen to audiobooks. The problem is that she doesn’t really get the hang of using electronics. He made things easy by building her a one-button audiobook player.

The Raspberry Pi board is a perfect solution for this project. It’s cheap, it has an audio port, it has storage for the books on the system SD card, and it runs Linux. The last part is key as it made things very simple when [Michael] started pulling together the various components.

When the RPi is powered up it drops immediately into a Python script which loads the audio track and places the music player daemon in pause. The yellow button seen above works as a play/pause button when clicked. If the listener misses something she can hold the button for more than four seconds to go back one track. Loading new books is easy too. [Michael] copies the files onto a thumb drive with a special volume label. When plugged into the RPi USB port the script automatically copies the book and starts playing when the drive is removed. He included a video demo on his project page linked above.

Hacking An Old Radar Gun To Interface With A Laptop

November 1, 2012 by 24 Comments

[Gregory Charvat] decided to see what he could do with this old Police radar gun. It is an X-band device that broadcasts continuous waves and measures the Doppler shift as they echo back. He cracked it open to see if he could interface the output with a computer.

After a little poking around he’s able to get it connected to a 12V feed from his bench supply, and to monitor the output with an oscilloscope. He established that it draws about 0.5A in current he built a companion board which uses AA batteries for power, and provides an audio output which can be plugged into his laptop’s audio-in jack. This technique makes reading the device as easy as recording some audio. From there a bit of simple signal processing lets him graph the incoming measurement.

In the video after the break you’ll see his inspection of the hardware. After making his alterations he takes it into the field, measuring several cars, a few birds, and himself jogging.

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Playing Video Games On Your Office Phone

November 1, 2012 by 25 Comments

So IT has your computer locked down, but if you’re lucky enough to have this model of telephone you can still play video games while at work. [AUTUIN] was at the thrift store and for just $8 he picked up an ACN videophone on which he’s now playing video games. We don’t know what magical second-hand stores sell functioning electronics of this caliber  but you should never pass up an opportunity like this.

It turns out the phone is running Linux natively. After some searching [AUTUIN] found that it is possible to telnet to a root shell on the device. Doing so he was able to figure out that the phone uses standard packages like ALSA for the Audio and /dev/input/event0 for the keypad. It even includes an SD card slot so he loaded one with a Debian image and used pivot_root to switch over to that OS. At this point the phone is his to command and of course he loaded up a video game which you can see in the clip after the break.

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Hackaday’s Official Kickstarter Policy

November 1, 2012 by 217 Comments

we don’t have one… yet.

We’re getting inundated with campaigns on crowdfunding sites like kickstarter and indiegogo. Sometimes they’re really cool projects, sometimes they’re not. Unfortunately, they are all basically appeals for coverage on hackaday so they can get money. That immediately puts a negative taste in our mouths. Then again, if a hacker legitimately makes something really awesome, why wouldn’t we want to help spread the word?

We don’t want to stop a really cool project from being shared with you just because it is on kickstarter, but we also don’t want to serve as a crowdfunding advertising platform. It ends up being complicated, especially if the idea is really cool, but the details are sparse.

So, what do you think? Share your thoughts on how hackaday should handle crowdfunding in projects.

p.s. This started as a rant about how sick of the constant pleas for kickstarter coverage we’re getting. We’re trying to stay positive and constructive here, please do the same in the comments.

 

Discrete FPGA Will Probably Win The 7400 Logic Competition

November 1, 2012 by 19 Comments

For this year’s 7400 logic competition, [Nick] decided to build an FPGA out of logic chips (Internet Archive cached version).

Perhaps a short explanation is in order to fully appreciate [Nick]’s work. The basic component of an FPGA is a slice, or cell, that performs boolean operations on its input and sends the result on its output. The core of these slices is a lookup table – basically a truth table that stores the result of every possible input combination.

One very easy way to implement a lookup table is to use a RAM or EEPROM chip. By tying the address lines of an EEPROM to the input and the data lines to the output, it’s possible to create a single slice of an FPGA very easily.

Unfortunately for [Nick], 74-series memories have long been out of production. There is another option open, though: shift registers. A shift register is basically an 8-bit memory chip with parallel inputs, so combining a shift register with an 8-input multiplexer is a very simple way to implement a 3-input, 1-output FPGA slice.

After figuring out how to tie these slices to bus lines, [Nick] needed a way to program them. Verilog or VHDL would border on insanity, so he wrote his own hardware description language. It’s certainly not as powerful or capable as the mainstream solutions to programming an FPGA, but it’s more than enough.

In the video after the break, you can see [Nick]’s overview of his very large 8-slice FPGA while he runs a combination lock and PWM program. All the code, schematics, and board layout are up on [Nick]’s git if you’d like to build your own.
Continue reading “Discrete FPGA Will Probably Win The 7400 Logic Competition” →

Hackaday Links: October 31st, 2012

October 31, 2012 by 3 Comments

LED Marquee Pumpkin

Here’s an LED marquee as the mouth of a Jack-o’-lantern which [Mike Skoczen] made. This comes hot on the heels of that playable Tetris Pumpkin. [Thanks Jacob]

Arduino-powered robot costume

This is a sideways view of the Arduino-powered costume [Dan] and his wife made for their son. It has lights, buttons, a character display, and makes noise.

Cylon Centurion from a pumpkin

Stuck inside because of the hurricane, [Shawn] and his girlfriend carved this Cylon Centurion pumpkin complete with lights and sound.

8×8 LED costume ‘face’

[Matthew] built this helmet which features an 8×8 RGB LED matrix as the face. He calls it the digital reaper. You can see him testing the electronics in this clip.

Makerspace costume roundup

[Jeff] wrote in to tell us about the Halloween preparations at the Port City Makerspace in Portsmouth, New Hampshire. Here we have a Ghost Busters Proton Pack, weeping angel wings from Dr. Who, and an Arc Reactor from Ironman.

OLPC Tablet Distribution Proves Concepts Laid Out In ‘The Diamond Age’

October 31, 2012 by 31 Comments

We don’t remember hearing about the One Laptop Per Child initiative distributing tablet computers but apparently a couple of shipments were distributed to rural communities in Ethiopia. The problem one might think of in this scenario is that the literacy rate in the two test villages was basically zero. But that’s exactly the population targeted with thr technology. The tablets were loaded with a software package called Nell. It was designed to guide a child in self learning by telling them engaging stories that include teachable moments. If you check out the white paper (PDF) you’ll find it’s pretty much the exact same teaching technique that [Neal Stephenson] wrote about in his book The Diamond Age. But keep reading that paper and you’ll see that this is because the researchers took their inspiration from that very novel.

Well the results are in and apparently [Neal] knows exactly what he is talking about. Not only did the children learn from the software, but within five months they were hacking the device (which runs Android) to get the disabled camera working.

[Thanks Alexander via Dvice]