Woot Lights And Mice Transplants

September 29, 2010 by Jakob Griffith 6 Comments

[Nathan Long] sent in two fairly simple mods he’s been working on. The first is the control of Woot-off Lights via LPT port. A computer checks Woot for the Woot-off logo, and if the logo is spotted, on go the lights. It’s really just a twist on the LED/Arduino email message system, but the creativity is nice.

His other modification is the stuffing of a Microsoft Intellimouse inside of a Logitech Wingman. With the goal of giving the old PS/2 mouse USB capabilities and removing the terrible ball. For those that are asking themselves “why bother? Terrible ergonomics, no scroll wheel, etc.” [Nathan] claims it’s for Quake 2 nostalgia, to each their own we suppose.

Making Your Own Lithium-ion Batteries

September 27, 2010 by Mike Szczys 23 Comments

You can make your own lithium-ion batteries if you have a source for individual cells and a control board to match your desired voltage levels. [Bill Porter] put together a quick tutorial where he makes a 14.4V 2.2 AH battery for about $10. He picked up a set of cable-modem backup batteries (used to make sure your bundled phone service doesn’t quit working when the power goes out) and tore out the cells. After reconfiguring the connections and swapping out the controller board the original 8V battery is now 14V. This doesn’t take into account any problems with battery life and charge leveling, but that’s a whole different tutorial waiting to happen.

If this type of battery hack is child’s play to you, take a look at a more involved lithium iron phosphate build.

You’ll Shoot Your Eye Out, Another Coilgun

September 23, 2010 by Jakob Griffith 41 Comments

All we needed to read was 4x 3900uF capacitor bank to know we had yet another decently sized homemade coilgun on our hands. And for the math buffs, that equates out to 1.25kJ of potential energy (efficiency kills it down to 37j of kinetic, but large numbers are more fun) which is more than enough to break skin; of course we recommend you just shoot old electronics rather than friends. On the more technical side, sure its only a single stage for now and we’ve seen some slightly more impressive triple stage guns, but it may just be more beautiful than our previously featured coil pistol. You guys be the judge. Catch a complete video after the jump of the internals and build process, skip ahead to 2:40 for the destruction.

[via TheDailyWh.at]

Continue reading “You’ll Shoot Your Eye Out, Another Coilgun” →

2-bit Paper Processor Teaches How They Work

September 23, 2010 by Mike Szczys 17 Comments

Take a few minutes out of your day, grab your scissors, and learn how a simple processor works. [Saito Yutaka] put together an exercise to teach processor operations with paper. After downloading the PDF you can cut out the Address and Data pointer as well as two-bit data tokens for each. The processor has three instruction sets; Increment register by one, Jump if not over flow, and Halt wait for reset.

Once you’ve got your cutouts you can follow along as the program is executed. The INC operation is run, with the JNO used to loop the program. Once the register has reached an overflow the overflow counter halts the program.

One word of warning, we think there’s a typo in one of the captions. Once the program starts running and gets to address 01(2) the caption still reads 00(2) for both address and data. As long as you compare the values in the picture along the way you should have no problem getting through execution. which has now been fixed.

Ben Heckendorn Gets His Own TV Show

September 17, 2010 by Mike Szczys 15 Comments

That’s right, Benjamin J. Heckendorn (aka Ben Heck) has started churning out episodes of his own Internet TV show. We finally got around to watching the first episode and enjoyed it greatly. You’ll see him alter an Xbox 360 controller for a disabled gamer, making custom foot interfaces to take over the traditional role of your right hand. Also in the episode is part of a big build; making an Xbox 360 laptop out of the new slim model. We’re very interested in that overall build, but in this episode you only see him removing the components from the factory case. But we guess the promise of seeing the rest of the project is the hook to get you to watch the next episode.

Think that you haven’t heard of Ben Heck before? If you’ve been following Hackaday for a while you have. We’ve looked in on quite a few of his builds over the years, including his pinball machine, Xbox 360 portable, and his access controller.

Building A Power Supply Around A DC-DC Converter

September 12, 2010 by Mike Szczys 15 Comments

The EEVblog is on a roll with interesting topics lately. In the latest episode [Dave] takes us through the nitty-gritty of switch mode power supply design. Using DC-DC converter IC’s in not especially hard. The datasheets tend to have fairly good usage schematics but there’s always a bit of heartache that goes into figuring out which external components will make for an optimal design. Get your calculator out and, in the video after the break, he’ll walk you through choosing component values based on the formulas for the MC34063 converter chip.

[Dave] makes the point that this is an extremely common chip, available from several manufacturers, and often found in consumer electronics. In fact, the switchmode supply hack from last month was using a regulator based around the MC34063. So you can buy it or scavenge for it. One thing to note though, we checked Mouser and Digikey and they’re pretty short on these chips right now. Plan your projects accordingly.

Continue reading “Building A Power Supply Around A DC-DC Converter” →

Projectile Speed Sensor

September 7, 2010 by Mike Szczys 16 Comments

[Mike] built a sensor rig to measure projectile speed. The setup uses a tunnel with two sensors in it. Each consists of a laser diode on one side focused on a photodiode in the other. The two are monitored by an op amp and measured by an ATmega128 microcontroller. When the beams are broken the elapsed time between the two events is measured in order to calculate speed. There is a setting to adjust the calibration for a range of speeds, which came in quite handy as [Mike] initially tested the device with rubber bands before moving on to a pellet gun and then a rifle.

It seems like he’s tempting fate by shooting a target just a few inches below his exposed circuitry but his marksmanship prevailed. We’ve seen bullet speed detectors in the past, used just for the delight of seeing how fast the projectile is moving, and also to capture an impact at just the right instant.