DIY Coffee Table Scale

September 6, 2009 by Jake W 16 Comments

scale

[Guus] screwed together this coffee table which doubles as a scale. No welding was required to put it together – just some bolts, pulleys, miscellaneous fittings, and an original design. The weight is indicated through the (unlabeled) position of the counterweight arm. Currently it is limited to measuring 10kg (22 pounds), but can easily be boosted by adding a heavier counterweight. It looks pretty robust, maintenance-free, and fitting for any living room workshop’s weighing needs. [Guus] is also the proud inventor of the rock radio, and he is working on creating Man-Y-Man: a modular play system allowing children to create up to 1520 unique creatures.

Tap-controlled Metronome

September 4, 2009 by Jakob Griffith 8 Comments

step13_06

[Adam] and his buddy [Matthew] sent in their tap-controlled metronome, or as they prefer, “metronome with an attitude.” Using the piezo speaker you can tap patterns and rhythm into the memory and it will repeat it back to you in loop. The two buttons allow you to speed up or slow down the beat which is indicated by an led array. As per their request, we mention its entirely on a PIC 16F, not an Arduino. Perhaps the most interesting part we found that’s definitely worth checking out was their amazingly detailed build process. Check out a quick video of the metronome in action after the break.

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Fire Horn

September 2, 2009 by James Munns 28 Comments

firehorn

Artist [Ariel Schlesinger] has managed to replace an air horn‘s compressed air tank with butane fuel. This hack manages to change the pitch of the horn slightly, as well as making one very noisy flamethrower. While not as impressive as other flamethrowers, this would probably take the cake for most achievable. Currently the site containing the how-to is down, but we would have to recommend not doing this at home anyway. Video after the jump.

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Bokode, A New Barcode

August 29, 2009 by Jakob Griffith 32 Comments

teaser

The MIT Camera Culture Group utilized Bokeh, an effect where the lens is purposely placed out of focus, in order to vastly improve current 2D barcode technology. Dubbed Bokode, the team claims that an off the shelf camera can read data 2.5 microns from a distance of over 4 meters, compared to today’s average barcode reader’s maximum distance of only a foot or so. What looks most interesting is the ability to produce a smoother and more accurate distance and angle calculations (relative to the camera): allowing for a better augmented reality. It also seems to be more secure than traditional 2D barcodes, that is of course until the hacker community gets a hold of it.

[Thanks Talin]

Beef Up Your UPS

August 28, 2009 by Mike Szczys 54 Comments

[Surferdude] was unhappy with the decreasing life of his aging uninterruptible power supply. He decided to beef it up using marine batteries. He extended the battery connections outside of the UPS case using #10 wire and swapped the two 12 volt gel cells with the heavy duty lead-acid batteries. Doing so upgraded the device from 20 amp-hours to 84 amp-hours at a cost of about $160. If you’re thinking about taking this on yourself, pay attention to the countinuous output rating of your UPS to prevent a fire risk.

Interfacing A Digital Rotary Switch

August 27, 2009 by Mike Szczys 19 Comments

digital_rotary_switch

[hw640] has put together a well written and detail packed explanation of how to interface with a digital rotary switch. These digital opto encoders have just two outputs with four possible logic levels (00, 10, 11, 01). The relative position of the switch is insignificant but the direction of rotation is what matters.

The short and dirty: Each of the switch’s 2 output pins is attached to a pin change interrupt on the microcontroller. Every time the switch moves it generates either a rising edge or a falling edge on one of the two pins; both edges cause an interrupt. By checking which pin caused the interrupt, then comparing the logic levels of the two pins after that interrupt, we can determine the direction the switch was rotated.

Although this explanation uses a PIC and code written in PicBasic Pro the concepts are discussed in the abstract and would easily be adapted to an AVR or another microcontroller of your choice.

Ubuntu Repository Crash-course

August 27, 2009 by Mike Szczys 13 Comments

[blip.tv ?posts_id=2542951&dest=-1]

[Alan] has just posted an Ubuntu screencast that will take you through a crash course in the Ubuntu repositories. If you are new to Ubuntu this will give you a much better grasp on how software repositories are handled.

The different types of updates are discussed: Security updates fix bugs that cause a system vulnerability. Updates (generic) are for bug fixes that aren’t a security threat. Proposed updates are for testing before an update hits the ‘updates’ section. Finally, backports are updates from a newer version that have been ‘backported‘ so systems running older versions of Ubuntu can have the benefit of newer features and fixed bugs.

He also provides some tips on selecting package sources (main, universe, restricted, and multiverse), and choosing the fastest mirror to reduce download times. This screencast is just part one and we hope to see 3rd party repositories, personal package archives, and repository caching covered in future installments.