Constructing A CO2 Laser Cutter

September 10, 2010 by Caleb Kraft 26 Comments

angler

[Owen] contacted us to show us his site dedicated to his CO2 laser cutter build. He spent about 2 years and roughly $15,000 putting it together, so this is not small build. The laser and optics alone were $9,000. This site isn’t necessarily meant to be a template to build your own, but he shares so much information that we would certainly suggest you read it before digging into a build. He does have some downloadables, like the tool paths and the emc2 configuration files as well as a copy of the entire website. Great job [Owen].

Binary Calculator

September 4, 2010 by Caleb Kraft 20 Comments

oooh, love those blue LEDs

[Syst3mX] emailed us about his Binary Calculator earlier this week and it almost slipped into the depths of our inbox. Luckily We noticed it in there today and thought we’d share.

He wanted to be able to calculate binary values without having to jump through hoops or boot up his computer, so he built his own binary calculator. For the brains, he chose an ATTiny2313. He can do basic operations like NOT, AND, OR, XOR, addition, subtraction, multiplication, division and modulo. It isn’t too bad looking either. You can catch a video of it in action after the break.

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Controlling An AC Drill Using One PWM Connection

August 31, 2010 by Mike Szczys 22 Comments

This peculiar setup allows [Ben Krasnow] to control an alternating current device using one pin on a microcontroller. He’s experimenting with a power drill and has relocated the trigger circuitry that makes it spin. On that board he found a variable resistor combined with a capacitor which control a triac, actuating the speed of a drill. [Ben’s] solution works great and isolates the drill from the control circuitry. He replace the variable resistor with a cadmium sulfide photoresistor (basically a variable resistor whose resistance depends on the intensity of light). Pulse-width modulation is used to adjust the brightness of an LED shining on that photoresistor and thereby affect the speed of the drill. This is such as simple alteration to the drill we’d call it MacGyver-esque.

See a demonstration after the break.

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Surgical Microscope Gets LED Retrofit

August 24, 2010 by Mike Szczys 16 Comments

[Roberto Barrios] picked up a surgical microscope to add to those other fun lab toys you seen in the background. These work very well when soldering small components because they don’t have to be as close to the viewed objects as traditional microscopes. But [Robert] didn’t care for the heat generated by the incandescent bulb so he build his own LED replacement. If you recognize his name it’s because we saw a beautifully crafted in-visor GPS system that he built back in April. This project exhibits the same level of craftsmanship in which he utilized the base of a spare bulb to add an LED, heat sink, and driver board that is adjustable on all three axes.

He also mentioned that he overhauled his site design and it now plays nicely with all browsers.

Chainsaw/flashlight Overkill

August 8, 2010 by Caleb Kraft 45 Comments

[Robbtoberfest] has earned our admiration with this crazy chainsaw powered spot light. It looks horribly dangerous, extremely inefficient, and woefully under engineered. We absolutely love it.

This could be plucked from a video game or a movie and seems to be one UV bulb away from being the ultimate post apocalyptic zombie vampire Armageddon weapon. He has taken apart a chainsaw and attached it to a DC treadmill motor using a couple of bike sprockets and a chain. That DC motor then feeds a car headlight directly. As you can see in the video, when he cranks the gas, it shines pretty brightly. The unfinished nature of this is due to a deadline for a contest on instructables, so he plans on adding a protective cowl, some fancy paint work, and a voltage regulator down the road.

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Dummy Loads And Heat Sinks

August 6, 2010 by Mike Szczys 21 Comments

In [Dave’s] latest episode of the EEVblog he takes a look at constant current dummy loads. These are used to test power supply designs and instead of just chaining resistive loads together every time he’s decided to look into building a tool for the job. What he ends up with is a reliable constant current load that can be dialed anywhere from 1.5 mA up to just over 1A. There’s even an onboard meter so you don’t have to probe the setting before use.

It may look like he sent his design off to the board house for production but that’s actually a re-purposed PCB. In walking though his junk-box assembled dummy load [Dave] shares some great tips, like using multiple 1% resistors instead of shelling our for one large and accurate power resistor. But our favorite part comes at about 12:00 when he takes us through some rough math in calculating heat sinks. We’ve always just guessed, but like any good teacher, [Dave] explains the theory and then measures the actual performance taking the guesswork out of the design. See for yourself after the break. Continue reading “Dummy Loads And Heat Sinks” →

Driving With Android

August 3, 2010 by Mike Szczys 5 Comments

[youtube=http://www.youtube.com/watch?v=tIx2ihZ7728]

[Elrik] converted an RC car so that it can be controlled with an Android phone. He wisely uses the accelerometer for steering with a button for forward and another for reverse. There’s even control for the headlights. The car itself has had a servo retrofit for steering but it’s the Bluetooth module that catches our eye. It’s a GP-GC021 which you can get your hands on for under $20. It has a serial UART for easy interface with a microcontroller at up to 9600 baud.

Now you can convert over that larger vehicle to use Bluetooth instead of WiFi, just don’t hurt yourself. And if you’re just starting out with writing Android apps, don’t miss our series: Android Development 101.