Laser Cutter Doubles As A 3D Printer

September 9, 2010 by Mike Szczys 10 Comments

[Bart] figured out how to use his laser cutter as a 3D printer. We’ve checked in on his open source laser cutter in the past and we’re happy to see he’s now done with the build. But rather than stop there he took it a step further. For less than $200 he built an extruder head and added RepRap circuitry. You can see in the image above the laser tube is in the background and the extruder head with a line of black filament is mounted on the gantry. [Bart] has other plans for extensibility as well, including a knife cutter, a pen plotter, and a Dremel mount.

76 Flaming Trombones Led The Big Parade

September 9, 2010 by Mike Szczys 36 Comments

[Jonathan Crawford] is ready and willing to fire things up with his flaming trombone. A couple of years back his band teacher was going through the storage room triaging instruments. This trombone suffered from a bad case of red rot and would never function well again so [Jonathan] was able to get his hands on it and get to work.

He started by sanding down the instrument and painting it with high-temperature spray paint. Flexible copper tubing intended for an ice maker was used to relocate the propane outlet inside the bell of the instrument. A barbecue igniter, controlled with the player’s left thumb, lights the flame.

The torch that [Jonathan] is using would only allow a small amount of gaseous propane to come out the nozzle. He ended up drilling out the aperture, and using a short piece of vinyl tubing to bridge the gap between the nozzle and the supplementary copper tubing. At full blast this allows liquid propane to escape so be warned.

You can see him demonstrating this indoors in the video after the break. He mentioned to us that the first time he tried this out he set off the smoke detector. You’ve got to be careful when playing with fire, whether it’s a musical instrument, or a wearable flamethrower. So, you know, don’t try this at home. Continue reading “76 Flaming Trombones Led The Big Parade” →

RFID Entry Uses Homemade Electronic Strike

September 9, 2010 by Mike Szczys 22 Comments

[Fileark] built an RFID entry system that uses a pretty ingenious alternative to an electronic strike plate. An electronic strike is a rather expensive hinged plate that mounts in the door frame and catches the door latch. But this system opens a set of double doors. The door without the handle is fixed in place and has a normal strike plate. But it also has a deadbolt mounted in line with that plate. When the deadbolt is extended it is flush with the strike plate, pushing the latch from the door knob back and freeing the door to swing open. This is a bit hard to put into words so watch the video after the break to clear things up.

The system uses a cheap RFID package that provides a single signal line. This line connects to an old VCR motor which turns the deadbolt. Timing is provided by a 555 chip, and the deadbolt movement is limited by a couple of switches mounted along with the motor.

Now that the unlocking mechanism has been built it would be simple to use other authentication methods for unlocking the door, like a wristwatch-based proximity system.

Continue reading “RFID Entry Uses Homemade Electronic Strike” →

Easy Quadrotor Helicopter Instructions

September 8, 2010 by Mike Szczys 19 Comments

Here’s a great tutorial on building your own quadrotor helicopter. This build isn’t necessarily less expensive than others we’ve seen since quality motors, propellers, and control circuitry aren’t cheap. But the design and assembly is well documented and presents a well-planned building procedure. The carbon-fiber tubes that make up the frame have extensions to protect the motors and propellers in the event of a crash. The Arduino, IMU, and transceiver are all tucked away between two aluminum body plates as well. They only thing missing is a solid methodology for tuning the four motors, a critical procedure that is just touched up at the end of the article.

Location Tracking With Twitter And Google Maps

September 8, 2010 by Mike Szczys 19 Comments

[Ryan O’Hara] built a location tracker he could use on motorcycle trips. Ostensibly this is to give his wife piece of mind be we think that was an excuse to play with GPS and SMS. To stand up to the trials of the road [Ryan] took his breadboarded prototype to the next level, using a manufactured board and a SparkFun enclosure. Tucked safely away is a PIC 18F25K20 gathering longitude and latitude from a GM862, formatting the info into a Google Maps link, and sending it to the Twitter feed via an SMS message. If you’re not familiar with the GM862, in addition to being a GPS module it can send and receive cellular data on a GSM network.

This is a nice solid hardware platform from which we can envision a couple of other hacks. The feed could be parsed to make a nice map graphic like the webpage for that Twittering Road Bike. It also might be nice to have a d-pad and character LCD to post your own tweets to the feed at the end of the day.

Serial Port Controlled CPU Fan

September 8, 2010 by Mike Szczys 38 Comments

[Christian] was running a Linux box as a home server but needed a way to quiet the noisy machine. Like many Linux servers, he’s using some pretty old hardware which doesn’t have an on-board header for the CPU fan which generates much of the unwanted sound. Those headers are nice because software can monitor the CPU and board temperature and adjust the fan accordingly.

[Christian’s] solution was to use the serial port for the task. He built a small circuit in which serial pin 3 drives the base of a transistor, pin 5 provides ground, and a floppy drive power cable supplies 5 volts. From there he wrote a RUBY program to monitor the CPU temperature and generate a PWM signal on the serial port, throttling the fan speed as needed.

[CC Photo Credit: Garrette via Flickr]

Face-slapping Security Gaff In Stored-value Cards

September 7, 2010 by Mike Szczys 39 Comments

The laundry machines at [Hans Viksler’s] apartment were converted over from coin operation to stored value cards. We’ve all dealt with these cards before and [Hans] thought it would be fun to do a little sniffing around at how this particular company implements them. We’ve covered how to read these cards and there have been several stories regarding how to bypass the security that they use.

But [Hans] wasn’t interested in stealing value, just in seeing how things work. So he stuck the card in his reader and after looking around a bit he figured out that they use the Atmel AT88SC0404C chip. He downloaded the datasheet and started combing through the features and commands. The cards have a four-wrong-password lockout policy. He calculated that it would take an average of over two million cards to brute force the chip’s stored password. But further study showed that this is a moot point. He fed the default password from the datasheet to his card and it worked.

We know it takes quite a bit of knowledge for the average [Joe] to manipulate these cards at home, but changing the default password is literally the very least the company could have done to protect their system.