Misc Hacks

4181 Articles

Destroying An Arduino’s EEPROM

May 16, 2011 by 20 Comments

We’ve seen projects test the lifespan of an EEPROM before, but these projects have only tested discrete EEPROM chips. [John] at tronixstuff had a different idea and set out to test the internal EEPROM of an ATmega328.

[John]’s build is just an Arduino and LCD shield that writes the number 170 to memory on one pass, and the number 85 on the next pass. Because these numbers are 10101010 and 01010101 in binary, each bit is flipped flipped once each run. We think this might be better than writing 0xFF for every run – hackaday readers are welcomed to comment on this implementation. The Arduino was plugged into a wall wart and sat, “behind a couch for a couple of months.” The EEPROM saw it’s first write error after 47 days and 1,230,163 cycles. This is an order of magnitude better than the spec on the atmel datasheet, but similar to the results of similar experiments.

We covered a similar project, the Flash Destroyer, last year, but that tested an external EEPROM, and not the internal memory of a microcontroller.

Check out the hugely abridged video of the EEPROM Killer after the break.

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USB Geiger Counter Hack

May 13, 2011 by 17 Comments

usb_geiger

[Vic] bought a Kvarts DRSB-01 Geiger counter a few years ago, and recently dug it out of his electronics stash. The counter is a run of the mil no-frills unit. It lacks any kind of LCD display and it cannot be calibrated, so Sievert exposure ratings are out of the question. The unit essentially monitors background radiation and alerts the user to the presence of gamma and high-energy beta rays via audible clicks.

[Vic] wanted to make it a bit more useful, so he decided to interface it with his computer in order to take long-term radiation measurements. He dug up a schematic online and deadbugged a small circuit using an ATtiny44. The circuit allows him to enumerate the electrical pulses generated by ionizing particles striking the Geiger tube, passing them along to his PC over USB.

The counter seems to interface with the PC just fine, but [Vic] does say that he’s getting some odd readings. He thinks that he might have damaged the tube while messing around, but he’s all ears if you have any insight on the matter.

Bringing The Game Of Tag Into The Digital Age

May 12, 2011 by 8 Comments

tagurit

How long has it been since you’ve played a game of tag?

[Sylvia Cheng, Kibum Kim, and Roel Vertegaal] from Queen’s University’s human media lab have concocted a fun twist on the classic game that just might compel you to start playing again.

Their game, called TagURIt, arms two players with Lumalive LED t-shirts which sport embedded touch sensors. A third player, known as the “chaser” attempts to touch either of the other players in order to capture the token displayed on the player’s chest-based LED matrix. The game is score-based, awarding points to the chaser for capturing tokens, while giving the other players points for avoiding capture.

If both players wearing the LED shirts are near to one another, the token will jump to the other player in an attempt to thwart the chaser. In this game, each player is a location-tagged URI, and proximity is determined by either tracking the users with cameras indoors, or via RF sensors if the game is played outside.

It is definitely an interesting way of playing tag, and we imagine it could be quite fun in large groups.

Continue reading to see a video demonstration of the TagURIt game being played.

[via Adafruit blog]

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Cheap Open-source Pace Clock Keeps Your Practice On Schedule

May 10, 2011 by 10 Comments

pace_timer

Pace clocks are used in a variety of sports, from swimming to track. The systems are typically expensive however, often beyond the reach of smaller organizations and underfunded programs. For their electrical and computer engineering final project, Cornell students [Paul Swirhun and Shao-Yu Liang] set out to build a much cheaper alternative to commercial pace clocks, with a far simpler wireless user interface.

Their clock uses an ATmega32a to handle all of the processing which is paired with a RN-42 Bluetooth module for communicating with Android smartphones. Their seven-segment displays are built using custom PCBs that they designed and fabricated for the project which are controlled by TLC5940NT LED drivers. The Android software allows users to connect to the pace clock remotely, creating any sort of multi-layered swimming or running routines.

When the project was completed, the pair tallied their total hardware cost to be under $250 apiece at low production volumes. Even when taking assembly time into account, their solution is several magnitudes cheaper than similar commercial systems.

Stick around if you are interested in seeing a demo video of their final product in action.

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DIY Sound Localization Sensor

May 10, 2011 by 32 Comments

sound_localization_sensor

Sound localization is very popular in law enforcement circles due to its accuracy and ability to quickly separate gunshots from other similar noises. These systems don’t come cheap, and after trying to build one himself, [Fileark] knows why.

He thought it would be neat to build a sound localization sensor based on how the human ear determines a sound’s source. Once he got started however, he realized just how hard it was to do localization just right.

He used an LM324N op-amp as a volume comparator, which he says works decently enough though he figures there are ICs out there that can do a better job. [Fileark] reports that the sound detector works well when the source is within about a foot of the sensors, but performance deteriorates at greater distances. He may consider using an ARM Cortex-M3 as his sound processor if he builds a second version, since the Arudino he used just doesn’t have enough power to sample and run calculations within the 10-50 microsecond window he requires.

Keep reading to see a video of his sound localization sensor in action.

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Roll Your Own Capacitors – High Voltage Edition

May 10, 2011 by 13 Comments

[Grenadier] tipped us off about his method for building your own high-voltage capacitors. He thought the paper and foil capacitor project was a nice introduction to the concepts, but at the same time he knew he could produce a much more powerful device.

For the dielectric he is using acetate film. This is the material from which overhead transparency sheets are made. He stuck with aluminum foil for the two plates. Just roll the foil flat with a rolling-pin, use thin wire to minimize the air that will be trapped between the dielectric layers, and make sure the foil plates are at least 4cm shorter than the acetate film on each end to prevent leakage. After rolling and securing the capacitor with zip ties you’ll be ready for the 3nF worth of fun seen in the video after the break. [Grenadier] mentions that this can be improved further if you were to vacuum impregnate the device with beeswax.

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Jeri Ellsworth’s Shooting Gallery

May 9, 2011 by 8 Comments

Back with another interesting vidoe, [Jeri Ellsworth] once again brings us an amusing and educational hack. This time she’s made a “shooting gallery” in the style of the old arcade games that actually used projectiles. In her version however, she’s using LEDs in the targets which are detected by the gun.  In an effort to keep the feel the same, she rigged up a pinball bell to ding at the appropriate times and it is quite effective.

As usual, she does a great job of breaking everything down and explaining how it all works. She shows us around her prototype so you can see how it is constructed, if you can make it through the solder gun shootout in the beginning.  If she were to continue with this project beyond the functional prototype stage, we’d love to see small video clips being displayed for the targets pepper’s ghost style. Maybe we’re just having fond memories of Time Traveler.