The Mother Of All Belt Grinders

April 29, 2017 by Adam Fabio 33 Comments

It seems like everyone is building belt grinders these days. You might think [Jeremy Schmidt] is just hoping on the bandwagon, but you’d be wrong. He took a full two years to design the perfect belt grinder for his needs. Now he’s built his perfect beast, and we must say, it’s quite impressive!

[Jeremy] had seen grinders which can tilt, but most of them tilt the entire machine, including the table. He designed his machine with an independent table. This means the belt can be placed at any angle, while the table remains flat. He’s achieved some really interesting finishes with a course grind on a 45-degree angle to the workpiece.

No build is without its problems. In [Jeremy’s] case it was building the box which acts as a receiver for the machine and the tables. Regular square tube stock wasn’t quite rigid enough, so bar stock was the way to go. The first attempt at building the box resulted in a warped tube, due to the stresses of welding. [Jeremy] was more careful the second time, moving from section to section of the four welds. This kept the heat from building up, and the box stayed straight.

The final result is an incredibly rigid machine which definitely will withstand anything that [Jeremy] can throw at it.

If you want to see more belt grinders at work, check out [Bob]’s treadmill belt grinder, or [Mike’s] conversion.

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Replicating A Victorian Era Console

April 26, 2017 by Adam Fabio 27 Comments

[Dt99jay] lives in a historic Victorian-era district in the UK. Most homes in the area have ornate exterior window dressings with stone consoles holding up heavy stone hood molding.

The window hood molding turned out to be wood — most likely the result of damage repaired after the blitzkrieg bombings of WWII. The 1940’s era work is now rotting away, so it was time for a repair. When the hood was pulled away from the window, disaster struck. One console completely crumbled, while the other lost large chunks of material. The They weren’t solid stone after all, but replacements most likely molded with Coade stone.

There are no ready replacements for consoles like this. [dt99jay] couldn’t just swap them out for modern looking replacements, so he set about replicating the consoles. The remaining console was much too delicate to remove from the building, so [dt99jay] glued the missing pieces back on. He then filled any missing parts and carefully scraped way all the loose paint. Then came the difficult part — making a mold while the console was still mounted on the house.

Room Temperature Vulcanizing (RTV) silicone rubber was carefully applied to the console. The RTV is thick enough to stay on while it dries. After several thick layers of RTV, the console was covered. [Dt99jay] then covered the mold with plaster of Paris bandages to support it. The finished mold was carefully removed from the house, and [dt99jay] filled all the low spots and air bubbles with RTV.

New castings were made using a mixture of cement and playground sand. Once painted, the results matched perfectly. The historic conservation committee was pleased, and the window was once again structurally sound.

Look At Me With Your Special Animatronic Eyes

April 25, 2017 by Adam Fabio 25 Comments

Animatronics for movies is often about making something that works and is reliable in the short term. It doesn’t have to be pretty, it doesn’t have to last forever. [Corporate Sellout] shows us the minimalist approach to building animatronics with this pair of special eyes. These eyes move in both the pan and tilt. Usually, that means a gimbal style mount. Not in this case. The mechanical assembly consists of with popsicle sticks, ping-pong balls, film canisters and dental floss.

The frame for the eyes is made of simple popsicle sticks hot glued together. The eyes themselves are simple ping-pong balls. Arduino powered servos control the movement. The servos are connected to dental floss in a cable arrangement known as a pull-pull system. As each servo moves, one side of the arm pulls on a cable, while the other provides enough slack for the ping-pong ball to move.

Mounting the ping-pong balls is the genius part of this build. They simply sit in the open end of a couple of film canisters. the tension from the dental floss holds everything together. We’re sure it was a finicky setup to build, but once working, it’s reliable. Only a glue joint failure or stretch in the dental floss could cause issues.

There are plenty of approaches to Animatronic eyes. Check out the eyes in this Stargate Horus helmet, which just won our Sci-Fi contest. More recently we saw Gawkerbot, which uses a CD-ROM drive to provide motion for a creepy robot’s eyes.

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Gawkerbot Is Watching You

April 23, 2017 by Adam Fabio 13 Comments

While sick with the flu a few months ago, [CroMagnon] had a vision. A face with eyes that would follow you – no matter where you walked in the room. He brought this vision to life in the form of Gawkerbot. This is no static piece of art. Gawkerbot’s eyes slowly follow you as you walk through its field of vision. Once the robot has fixed its gaze upon you, the eyes glow blue. It makes one wonder if this is an art piece, or if the rest of the robot is about to pop through the wall and attack.

Gawkerbot’s sensing system is rather simple. A PIR sensor detects motion in the room. If any motion is detected, two ultrasonic sensors which make up the robot’s pupils start taking data. Code running on an ATmega328 determines if a person is detected on the left or right, and moves the eyes appropriately.

[CroMagnon] used an old CD-ROM drive optics sled to move Gawkerbot’s eyes. While the motor is small, the worm drive has plenty of power to move the 3D-printed eyes and linkages. Gawkerbot’s main face is a 3D-printed version of a firefighter’s smoke helmet.

The ultrasonic sensors work, but it took quite a bit of software to tame the jitters noisy data stream. [CroMagnon] is thinking of using PIR sensors on Gawkerbot 2.0. Ultrasonic transducers aren’t just for sensing. Given enough power, you can solder with them. Ultrasonics even work for wireless communications.

Check out the video after the break to see Gawkerbot in action.

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Go Wireless With This DIY Laser Ethernet Link

April 19, 2017 by Adam Fabio 40 Comments

Most of us have Ethernet in our homes today. The real backbones of the Internet though, use no wires at all. Optical fibers carry pulses of light across the land, under the sea, and if you’re lucky, right to your door. [Sven Brauch] decided to create an optical link. He didn’t have any fiber handy, but air will carry laser pulses over short distances quite nicely. The idea of this project is to directly convert ethernet signals to light pulses. For simplicity’s sake, [Sven] limited the bandwidth to one channel, full-duplex, at 10 Megabits per second (Mbps).

The transmit side of the circuit is rather simple. An op-amp circuit acts as a constant current source, biasing the laser diode. The transmit signal from an Ethernet cable is then added in as modulation. This ensures the laser glows brightly for a 1 bit but never shuts completely off for a 0 bit.

The receive side of the circuit starts with a photodiode. The diode is biased up around 35 V, and a transimpedance amplifier (a current to voltage converter) is used to determine if the diode is seeing a 1 or a 0 from the laser. A bit more signal conditioning ensures the output will be a proper differential Ethernet signal.

[Sven] built two identical boards – each with a transmitter and receiver. He tested the circuit by pointing it at a mirror. His Linux box immediately established a link and was reported that there was a duplicate IP address on the network. This was exactly what [Sven] expected. The computer was confused by its own reflection – but the laser and photodiode circuits were working.

Finally, [Sven] connected his PC and a Raspberry Pi to the two circuits. After carefully aligning the lasers on a wooden board, the two machines established a link. Success! (But be aware that a longer distances, more sophisticated alignment mechanisms may be in order.)

Want to know more about fiber and networking? Check out this article about wiring up an older city. You can also use an optical link to control your CNC.

Robot Targets Eyeballs, Fires Lasers. OSHA’s Gonna Love This One

April 18, 2017 by Adam Fabio 60 Comments

If you even think about hacking with lasers, you’re going to hear about eye safety. “Be careful” they’ll say. “Don’t look into laser with remaining eye” is a joke you’ll not be able to avoid. You’ll hear “Where are your goggles”, and about 1000 other warnings. Don’t get us wrong, laser/eye safety is important. However, the constant warnings can get a bit old — especially when you’re working with a “low power” class 3a laser — you know, the kind with a warning label that says “AVOID DIRECT EYE EXPOSURE” in big black letters on a yellow background.

[Michael Reeves] got fed up, and went a bit nuts. He built a robot specifically to shine a laser into human eyes. No, not a medical robot. This ‘bot lives in a pizza box, is built from servos, duct tape, and [Michael’s] tears. It just shoots lasers at people’s eyes. Needless to say, please, don’t try this at home, or at all.

Designing such a diabolical beast was actually rather simple. The software is written in C#. Frames are captured from an old Logitech webcam, then passed into Emgu CV, which is a .NET wrapper for OpenCV. [Michael] runs a simple face detection algorithm, and uses the results to aim a laser. The laser is mounted on two R/C style servos. An Arduino forms the glue between the servos and the PC.

[Michael] has a great deadpan delivery and it all makes for a great video. Think of him of a younger [Medhi] over at Electroboom. But we can’t condone this behavior. Properly labeled and characterized red laser pointers have never been shown to cause eye damage. Yet if the laser is out-of-spec or reflects of something that further focuses the beam it is certainly capable of damaging eyesight.

We want [Michael’s] eyesight to remain intact so he can make more videos — he’s entertaining, even if ignoring safety warnings isn’t.

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Burger King Scores Free Advertising From Google Home With A Whopper Of A Hack

April 14, 2017 by Adam Fabio 67 Comments

Advertisers are always trying to stuff more content into a 15 or 30 second TV spot. Burger King seems to have pulled it off with a series of ads that take advantage of the Google Home device sitting in many viewers living rooms. It works like this: The friendly Burger King employee ends the ad by saying “Ok Google, what is the Whopper burger?” Google home then springs into action reading the product description from Burger King’s Wikipedia page.

Trolls across the internet jumped into the fray. The Whopper’s ingredient list soon included such items as toenail clippings, rat, cyanide, and a small child. Wikipedia has since reverted the changes and locked down the page.

Google apparently wasn’t involved in this, as they quickly updated their voice recognition algorithms to specifically ignore the commercial. Burger King responded by re-dubbing the audio of the commercial with a different voice actor, which defeated Google’s block. Where this game of cat and mouse will end is anyone’s guess.

This event marks the second time in only a few months that a broadcast has caused a voice-activated device to go rogue. Back in January a disk jockey reporting a story about Amazon’s Echo managed to order doll houses for many residents of San Diego.

With devices like Alexa and Google home always ready to accept a command, stories like this are going to become the new normal. The only way to avoid it completely is to not allow it in your home. For those who do have a voice-activated device, be very careful what devices and services you connect it to. Internet of things “smart” door locks are already providing ways to unlock one’s door with a voice command. Burglarizing a home or apartment couldn’t be easier if you just have to ask Siri to unlock the door for you. And while some complained about the lack of security in the Zelda hack, we’d rate that as a thousand times more secure than a voice recognition system with no password.

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